Digital Open-File Geological MapsOf West Virginia

National Parks Service Mapping Project Handbook

GIS Layer Digitizing Guidelines, Project Procedures, Data Model, and Technical Issues

West Virginia Geological and Economic SurveyMont Chateau Research Center

1 Mont Chateau Road Morgantown, WV 26508

(304) 594-2331 Revised by Sarah Gooding, Geologist and Digital Cartographer,

April-May 2010 for NPS Project use.

Adapted from original document prepared for WVGES by Kurt Donaldson and Eric Hopkins, 2003, WV GIS Technical Center,

with excerpts from Proposal for Geologic Mapping in Three West Virginia National Park Service Units prepared by Paula Hunt, WVGES, August 2009.

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Table of Contents:

Introduction ………………………………………...………………………………….. 1

Deliverables, Overall NPS Project………………...……………………………………. 2 Overall NPS Project Location and Quadrangle Map…………………………………… 3 Deliverables, Concord NPS Team ………………...…………………………………… 4 Project Setting……………………………………...…………………………………… 5 Conversion process….………..………………………………………………………… 6

I. Scanning and georeferencing geologic quadrangle maps…………………………..6

II. Capturing geologic features……………………………………………………......7 Feature collection sequence, layers collected.…………………………………8

III. Feature attribution and symbology Polygon, line, and point features......................................................................12

IV. Edgematching…………………………………………………………………....14

V. Quality control…………………………………………………………………....15

Appendices

Appendix I. Geology GIS layer descriptions, Data Model….…………………………..16 Appendix II. Cartographic symbol legend……………………………………………….23 Appendix III. Checklists for quad digitizing and QA/QC procedures...……………….....24 Appendix IV. The Polygon Building and Topology Process……………………………..27Appendix IV. Figure 7: Geologic Map Digitizing and Topology Process Flowchart...….38 Appendix V. Instructions for Digitizing Cross Sections and Stratigraphic Columns…....39

On the DVD-ROM:

Digital Copy of this Document in Adobe PDF format Quadrangle Index Map shapefile for the project idx_24k_utm83.shp (and in UTM 27) WV county boundary shapefile for the project county_24k_drg_utm83.shp (and UTM 27)Geologic Quad Digitizing Checklist in Microsoft Excel and Adobe PDF formats Geologic Quad QA/QC Checklist in Microsoft Excel and Adobe PDF formats Geologic Map Digitizing and Topology Process Flowchart in Adobe PDF format Figure 2. National Park Service Units in WV Quad Index Map in Adobe PDF formatExample Bedrock Geologic Map dataset for Shady Spring Quad, WV (in WVGES Data Model) Example Surficial Geologic Map dataset for Blackwater Falls Quad, WV (in Kite, 2003 Data Model) Guidelines For Preparation of Surficial Geology Quadrangle Maps For West Virginia And Adjacent States (A Working Document) J. S. Kite, 2003, in Adobe PDF format

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INTRODUCTION

PurposeDigital map conversion (Figure 1b) of geologic features drawn by the West Virginia Geological and Economic Survey (WVGES) and others on U.S. Geological Survey (USGS) 1:24,000-scale topographic base maps (Figure 1a) is an important, long-term goal. This National Park Service Mapping Project Handbook describes the procedures to be followed by project members and the expected final product specifications for the conversion of hand-drawn geologic maps into a form usable in a geographic information system (GIS). To ensure consistent and high-quality edgematched GIS-ready geologic and surficial maps in time to meet tight project deadlines, it is very important that all NPS project members, in all locations, use the same digitizing, processing and quality control procedures and the same project data model, all of which are provided in the text and appendices of this handbook. Associated base map layers, charts and checklists to be used in the project, example datasets, and a digital copy of this document have also been provided on the accompanying media disc.

Project ScopeThis project includes all West Virginia geologic quadrangles mapped under the National Park Service (NPS) project. The West Virginia Geological Survey (WVGES), working with professors and senior to graduate-level geology and geography students from Concord University and West Virginia University, are going to map the surficial and bedrock geology of three natural area park units located in West Virginia: Bluestone

Figure 1a: Hand-drawn geologic features on USGS 1:24,000-scale topographic map.

Figure 1b: Geologic map digital conversion.

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National Scenic River (BLUE), Gauley River National Recreation Area (GARI), and New River Gorge National River (NERI).

The goal of this project is to produce 1:24,000-scale digital surficial and bedrock geologic maps along with their respective geodatabases using an appropriate and well-documented data model. Bedrock geology will be mapped for BLUE, NERI, and GARI,and the fourteen United States Geological Survey (USGS) 7.5-minute topographic quadrangles they are contained within (see Figure 2). Surficial geology will be mapped within the park boundaries for BLUE, NERI, and GARI (Figure 2).

These maps will be added to the digital geologic database of West Virginia quadrangles that have been mapped under other projects and have been digitized and converted into GIS layers, to create a complete digital collection of all geologic mapping at 1:24,000-scale in West Virginia.

OVERALL PROJECT DELIVERABLES TO NPS:

Final map products delivered to NPS will include:

A digital geologic map for each 7.5-minute topographic quadrangle in ESRI ArcGIS® 9.x or latest version;

All maps seamlessly edge matched with each other and with other mapping on adjacent quadrangles;

A personal geodatabase (.mdb) for each digital geologic-GIS map with a Geologic Unit Information table and Source Map Information table, where applicable. All geologic features on the published map(s) will be present as GIS data and will be fully attributed shapefiles to standards identified in Part I d of the USGS-NCGMP 2004 STATEMAP program announcement No. 04hQPA0003 or some other mutually agreed-upon data model. WVGES will deliver a product that can be seamlessly integrated within the existing Park Service GIS;

Accompanying text and graphics containing map explanatory information;

A description of map units;

A cross section showing sub-surface interpretation;

A stratigraphic column depicting stratified units;

Where applicable, a correlation diagram showing age relationships of map units;

An explanation of map symbols; and

Appropriate (FGDC or similar mutually agreed-upon format) metadata for all geodatabases produced. WVGES understands the importance of the data model and metadata, and will deliver a product that can be seamlessly integrated within the existing Park Service GIS.

These digital products will be delivered via CD-ROM, file transfer protocol (ftp), or some other agreed-upon electronic medium. Geologic maps produced under this contract will meet those standards as identified in Part I d of the USGS-NCGMP 2004 STATEMAP program announcement No. 04hQPA0003.

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CONCORD MAPPING/GIS CONVERSION TEAM DELIVERABLES

Digital Geological Open-File Map Products Delivered By Concord Team to WVGES Will Include:

1) ESRI ArcGIS geodatabases with individual map layers as described in the data model in Appendix I. Layers are named according to feature type and the USGS 7.5-minute topographic quadrangles from which they were drawn, following naming conventions as described in Appendix I. Georeferenced scanned images of USGS 7.5’ topo maps will be used as the base maps for all mapped quadrangles. The Quadrangle Index Map shapefile idx_24k_utm83.shp (and a utm 27 version) and the WV county boundary shapefile county_24k_drg_utm83.shp (and a utm 27 version) will be used for georeferencing and for all output maps by all project members, to ensure consistency and accuracy of all maps and layers produced. These shapefiles have been provided on CD-ROM by WVGES to all project members.

2) Digitized and attributed cross-sections, stratigraphic columns, etc that may accompany a map, drawn in ArcMap at 1:24,000 scale, following procedures outlined in this handbook and conforming to the data model in Appendix I.

3) ArcMap map documents (.mxd files), validated Topology layers, and layer rendering files (.lyr files) used in the final stages of the conversion process and preliminary quality-control checking for each quadrangle map or diagram.

4) Completed hard-copy Digitizing and QA/QC Checklists for each mapped quadrangle. These are provided in Appendix III, and digital copies are also provided in Microsoft Excel format for printing and use by project members.

5) All maps seamlessly edge matched with each other and with other previous mapping on adjacent quadrangles.

6) Hardcopy plots at full scale of any original geologic maps, cross-sections, stratigraphic columns, etc generated by the Concord geologic mapping team.

7) Scanned and georeferenced images of all original geological open-file maps, cross sections, and any other source material that may accompany a quadrangle.

8) Open-File Report of Investigations text documents and any other explanatory or supporting materials that accompany the original map (in Microsoft Word or Adobe PDF format where possible).

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PROJECT SETTING

Need for Better Resolution Geologic MapsThe digitized 1968 Geologic Map of West Virginia is the only seamless geology GIS file that exists for the entire State. Because of its poor spatial resolution and generalized geologic unit representation, it was determined that this 1:250,000-scale geologic map should be updated with more accurate 1:24,000-scale geologic data (Figure 3).

GIS Software PlatformWVGES uses ESRI’s ArcGIS software, along with various vector data formats(e.g., ArcInfo coverages, shapefiles, and geodatabases), and raster images (Grids, JPG, TIFF) to perform the conversion. The main vector file formats preferred for this project are shapefiles and geodatabases, due to their portability and widespread compatibility with other types of GIS and CAD software. The main raster file format preferred for this project is 400dpi indexed-color TIFF file-format scanned images of original maps due to their superior image quality and ease of georeferencability.

Coordinate SystemAll GIS layers are cast on the Universal Transverse Mercator (UTM) projection, Zone 17, most using datum NAD 83, with units in meters. However, some quadrangles might use datum NAD 27, and the datum used is usually noted in the filename of the quadrangle boundary polygon shapefile that accompanies each set of GIS geology layers. Projection files (with a .prj file extension) must also be provided for each shapefile layer in the project. World files (.tfw or .jpgw file extensions, ArcMap .aux files, etc) must also be provided for any georeferenced raster layers that accompany the vector data.

OwnershipAll digital and hardcopy products are the property of the WVGES and NPS and will be distributed by them on a request basis. WVGES reserves the right to maintain, edit, and update all digital and hardcopy products without notice to the consumer.

Figure 3: Comparison of 1:250,000-scale geologic map (dark blue lines and labels) with more accurate 1:24,000-scale geologic map.

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DisclaimerThe Open-File Geological Map publications represent interpretations of best-available data made by professional geologists. As in all research work, professional interpretations may vary, and can change with advancements in both technology and data quality. These publications are offered as a service of the State of West Virginia;proper use of the information herein is the sole responsibility of the user.

THE CONVERSION PROCESS: A Quick Overview:

The initial steps of the digital conversion require that the geological information on the original map be scanned and georeferenced. Digitizing in ArcMap then captures the various geological features such as faults, folds, strike & dip points and contacts. Thenlinear or polygon topology is created, validated and checked, and finally features areattributed. Next, attributed features are edgematched to corresponding features of adjacent quadrangles. In the cartographic map production phase, hardcopy or print-ready electronic versions are made with the appropriate map symbols and annotation. Throughout the conversion process, quality control checks are done (Figure 4). All of these processes will be explained in much more detail in the rest of this handbook and the Appendices. For a much more detailed flowchart, see Figure 7, the Geologic Map

Digitizing and Topology Process Flowchart.

Figure 4: Generalized Flowchart of the digital conversion process.

THE CONVERSION PROCESS: Details:

I. Scanning and Georeferencing 1:24,000 Geologic Quadrangles

Scanning

Paper or mylar topographic quadrangles with hand-drawn geologic information, createdby WVGES and Concord geologic mapping teams, are scanned directly to greyscale orindexed-color TIFF files using a high-resolution scanner at an optical resolution of 400dpi (usually) (Figure 1a).

Scanning

Drawing

Topology Attribution Edgematch

Georeferencing

Map Production

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Georeferencing in ArcMap

The scanned geologic quadrangle maps are next georeferenced in ArcMap to the UTM NAD 1983, 7.5-minute Quadrangle Index Map shapefile idx_24k_utm83.shp in a new map project (see instructions given in ArcMap Help for “Georeferencing a raster dataset”and be sure to use the correct set of corner tic marks!). It is important that all project members use the provided shapefile idx_24k_utm83.shp for all stages of the NPS project, to ensure the consistency and accuracy of the entire project, and that all data produced will integrate seamlessly into WVGES and NPS databases.

It is often much simpler to deal with just one quadrangle boundary polygon instead of the entire state of WV index map layer. The individual quadrangle for a particular map may first be selected and then exported out of the main WV index map as a separatequadrangle polygon layer for georeferencing and digitizing procedures. It is imperative that the quad polygon be extracted only from the idx_24k_utm83.shp shapefile. It is also extremely important that the resulting quad boundary polygon never gets selected and accidentally edited or moved around during digitizing! Be sure to make it a non-selectable layer in the ArcMap Table of Contents (TOC) before performing any georeferencing or digitizing of map layers.

II. Capturing Geologic Features

Arc Directionality: Direction matters! Arcs for linear features such as faults and folds have a directional component to correspond with the correct mapping symbols for printed maps. Note that some feature symbols are not symmetrical, e.g., thrust faults with “saw teeth” to one side only, or have directionality, e.g., plunging or overturned fold axes. Features need to be flipped after drawing(symbolize the feature to check the direction of thrust fault teeth, etc) or initially drawn in the correct direction to save the extra step. Features like this usually also contain an attribute in the data model that specifies the type and direction of movement, such as the Fault_Type attribute in the FLT (Faults) layer.

Pseudonodes: Pseudonodes are added at intentional locations to capture changes in attributes of line features such as the confidence value attribute of geologic contact lines. When a contact line changes from a solid (certain) line style to a dashed (approximately located) line style, a pseudonode will exist between the two line segments. Each line segment will have the appropriate value from the data model for its Confidence attribute, and can then be symbolized differently on the resulting map.

Snapping: For the NPS project, it is expected that all line intersections will have correct topological integrity. This means that only line “ends” of line-type feature class layers can interact with each other. Snapping on the ArcMap Editor toolbar must be set to “Line Ends” ONLY. (Only the quadrangle polygon can have snapping set to “Edge”. Lines may snap to the “Edge” of the quad boundary, but may only be snapped to “ENDS” of each other within the map layer. If linesget snapped to other line “Edges” within a map layer, this will not be topologically correct and might be the source of intersection errors.)

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FEATURE COLLECTION SEQUENCE

1. Geologic Formation Contacts, CNT (Line and Polygon)Bedrock geology is mapped according to its geologic time period, i.e. Eocene, Mississippian, Devonian, Silurian, etc; and geographic type location, i.e., Marcellus Shale, Oriskany Sandstone, Tonoloway Limestone, or Juniata Formation (a group of several related rock types). The “contacts” are lines separating different geologic units, and are drawn solid, dashed, or dotted, according to how confident the author is in the line’s location. Care should be used in interpreting the confidence value of contact lines that coincide with faults, to ensure that the two layers match.

Marker beds, such as thin sandstones and coal beds, that also form geologic unit boundaries, and are too thin at 1:24000 scale to be a polygon, are drawn in the CNT line layer, and are also given the unit abbreviation attribute. Marker beds and coal beds that are significant enough to be mapped, but do not form geologic unit boundaries, are captured in another layer, the COAL line layer, see description below.

Geologic formation contacts are collected as lines, which are then used with the quadrangle boundary to generate formation polygons. This is done to ensure that the contact lines are completely co-incident with the polygon boundaries, and minimizes topological problems such as gaps, overlaps, and doubled-up polygon boundaries caused when polygons are digitized as polygons instead of generated from linework. The polygons formed by the contacts are then run through several cycles of topological checking to resolve any digitizing errors in the linework and make sure that all polygons are formed. Refer to the detailed instructions on “The Polygon Building and Topology

Process” in Appendix IV and to Figure 7, the Geologic Map Digitizing and Topology

Process Flowchart for a step-by-step guide to this cyclic process.

Polygons are then labeled with the letter symbols used to represent the geologic units, i.e., “Do” for Devonian Oriskany, or “Sto” for Silurian Tonoloway Limestone, and so on. Unit Abbreviation Symbols and descriptions of geologic units for each quadrangle can be found in the Open-File Report of Investigations document that usually accompanies each Open-File Geological Map. Attempts have been made to use a consistent and unique unit abbreviation symbol for each unit across all quadrangles mapped digitally. The geologic unit polygons layer contains a special label field, “GeoAge_Label” to properly label the units on any maps produced, using the True-Type Font “geoageFullAlpha”, which is provided along with the dataset.

Figure 5: Digitized geologic features: formation units, faults, folds, strike/dip measurements, and cross-sectional lines.

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Errors, omissions, and inconsistencies may be noted in the original open-file texts and paper maps; edits to the final digital GIS layers and map layouts should be made to ensure that the digitized version of the map is as accurate, up-to-date, consistent, and complete as possible. Any errors fixed during the GIS process, or any other deviations required from the original map should be noted on the Geologic 7.5’ Quad Digitizing

Checklist found in Appendix III, to document all changes made from the author’s original work, subject to the author’s final approval.

2. Faults, FLT (Line Features)Faults, which are coincidental with geologic formation contacts, are collected right after contact lines. The fault vectors are copied and pasted from the CNT line layer to the FLT line layer, and then the attributes are converted to those of the Fault layer (See Appendix I) This method ensures that the coincident faults and contacts features have the same exact vertex coordinates, by making sure that the line is only ever drawn ONCE. Faults are shown on the paper maps as solid, dashed, or dotted lines to indicate the confidence in their placement. Thrust faults are distinguished from others by the added “saw tooth” line decoration which shows direction of movement of the thrust fault (Figure 5).Relative motion along normal fault lines is indicated by “U” (up) or “D” (down) on the map. Relative motion along strike slip faults is shown with arrows on each side of the fault line. The direction and type of motion is included in the GIS layer as an attribute, along with feature confidence attributes and fault names for structures that are named on the map. This layer is one of the layers in which line direction matters, so faults should be symbolized with the correct line symbol (especially thrust faults) to make sure the symbol faces the correct direction.

3. Structural Fold Axes, STR (Line)Fold axes are distinguished from other lines by their double-headed arrow symbols; arrows pointing out for anticlines (convex upward folds) and in toward the axis line, for synclines (concave upward folds). A terminal arrow on one or both ends of the axis line itself indicates plunge. The confidence attributes used for faults and contacts also applies to this layer as well as fold names for structures that are named on the map. This layer is one of the layers in which line direction matters, so folds should be symbolized with the correct line symbol (especially plunging and overturned folds) to make sure the line symbol faces in the correct direction.

4. Bedding Orientation, BED (Point)The orientation of rock layers is measured at various outcrops and depicted on the geology maps using strike and dip symbols. These points are in some cases first given arbitrary station numbers on paper, which are used in some quads to join the digitized points to an Excel spreadsheet of strike and dip information. Some quads do not need station numbers, as the bedding points and their data are digitized directly off the source map, or downloaded from a handheld field device.

In the WVGES data model, the strike and dip direction values should be converted from a relative direction field-style measurement (e.g., strike N10 deg W; dip 35 deg NE) into an azimuth measurement which uses an absolute value within a 360-degree system for strike and also for dip direction. Using the above strike example this would be Azimuth = 350, Dip = 35, Dip-Direction = 80.

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The azimuth-style values are used to correctly orient the strike and dip symbols using the “Rotation Field” option in Advanced symbol settings, to calculate the dip direction field (which is always perpendicular to strike), and to place the dip angle labels in the correct position on the finished maps using the “Rotation field” options in the label symbology settings.

In some quadrangles, an absolute strike value is not available, just the strike symbol is oriented on the paper or mylar map. In this case, an angle measurement tool is used in ArcMap to measure the azimuth value from the strike symbol off the scanned and georeferenced original map.

5. Cross Section Location, XSC (Line)These lines are drawn across the map where geologists plan to make more extensive subsurface interpretations of the surface geology. They are marked with letters at each end, e.g., A-A’, B-B’. Confidence levels do not apply to these features, the only attribute is the quadrangle name and the endpoint letters for each line on the map. The cross section diagram itself is digitized in another set of feature classes/layers, discussed below.

Naming conventions: Cross section diagram layers are named with the lowercase “xsc” in the filename to differentiate them from this cross section location line map layer, which has “XSC” in the name in all-caps.

6. Igneous Intrusive Features, ILN (Line)These small and rare features (e.g., dikes, sills) are captured in their own GIS layer. The confidence symbology used for faults and contacts applies to this layer. They are also given a unit abbreviation attribute and an attribute for composition/rock type, if known. Any intrusive features large enough to be polygons instead of lines at 1:24000 scale are included in the geological contacts line/polygon layers instead. These features are rare and are only usually exposed around Pendleton County, WV.

7. Coal Beds and Non-Contact Forming Marker Beds, COAL (Line)Line layer for linear geologic features such as coalbeds, fireclays and sandstone marker beds that are only a line width at 1:24,000 scale, and do not form unit contacts. (Beds that form unit boundaries should be in the CNT geologic contacts line layer.) Attributes include Type, Confidence, Symbol, full marker bed/coal name, and unit abbreviation.

8. Coal (or Sandstone) Structural Contours, “<Quadname>_<CoalName>_STC” (Line)Structure contour elevation lines drawn on a particular bed(s), usually coals or sandstones, with elevation, unit name abbreviation, confidence and symbol attributes.Some maps show contours for multiple beds, these should be drawn in separate layers, with the bed name in the layer title.

9. Surficial Geologic Contacts, SRF and/or QAL (Line and Polygon)

QAL: On maps showing simplified Surficial geology such as only Quaternary alluvium, terraces, artificial fill, mine dumps etc, the QAL line and QAL_poly layers can be captured if the original map shows concealed bedrock contact lines. If no concealed bedrock contacts are shown, QAL and related units will be included in CNT and

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CNT_poly as a unit abbreviation. QAL lines and polygons are captured using the same linework-generated polygon method as the CNT and CNT_poly layers, and should also be run through several cycles of topological checking to resolve any digitizing errors in the linework and make sure that all polygons are formed prior to giving them attributes.

SRF**: On maps where more detailed Surficial geology is shown, usually on a separate map sheet from the bedrock geology, the SRF line and SRF_poly layers can be captured. SRF lines and polygons are created using the same linework-generated polygon method as the CNT and CNT_poly layers. Surficial lines and polygons should also be run through several cycles of topological checking to resolve any digitizing errors in the linework and make sure that all polygons are formed prior to giving them attributes. Refer to the detailed instructions in Appendix IV and to Figure 7, the Geologic Map Digitizing and Topology Process Flowchart for a step-by-step guide tothis cyclic process.

**The Kite (2003) Data Model is to be used for NPS Surficial Maps, published as Guidelines For Preparation of Surficial Geology Quadrangle Maps For West Virginia And Adjacent States (A Working Document) by J. Steven Kite of the Department of Geology and Geography, West Virginia University, August 2003 Revision. This document will be provided to NPS team members under separate cover and on the disc.

10. Digitized Cross Sections (“xsc”), and Stratigraphic Columns (“<quad>_Strat_#”) The cross section location line (i.e., A-A’ line) is accurately measured off the original source map to an accuracy of hundredths of an inch with a scale ruler. This measurement is used to build a cross section frame at the correct size at 1:24,000 scale (also commonly referred to as 1 inch : 2000 feet) in ArcMap, so that it will print out at the correct size on the finished map publication. The cross section frame is generally drawn at some rough distance below the map quadrangle, so that the cross section and the geologic map could be shown in the same map data frame, if desired. The cross section shares the same coordinate system as its corresponding geologic map for this reason (although this is an “artificial” and arbitrary geographic space for the cross section.) The sections do not have “Z” (3-D vertical) dimension values in ArcMap.

Cross sections are included for diagrammatic interpretive purposes, but their dimensions (size and scale) must match the map’s exactly. The frame is built to 1:24,000 scale (1in:2000ft) horizontally and vertically, given elevation attributes along the vertical axis, and the scanned cross section image is then georeferenced to it. The cross section isdigitized as line features, with a Type attribute for contacts/faults, and a Confidence attribute for line symbolization. Contact polygons are then generated using the contact lines and the cross section frame, and given the same unit abbreviation symbol attributes as the corresponding geological map. If there are any non-contact-forming coal beds or marker beds shown in the cross section, they are drawn in a separate line layer, and also given the same unit abbreviation symbol attributes as the corresponding geological map. On map layouts, geologic units are given the same symbols in both the map and the cross section, with the exception of units that do not crop out are rendered in shades of grey in cross section. The geologic unit polygons layer contains a special label field, “GeoAge_Label” to properly label the units on any maps produced, using the True-Type Font “geoageFullAlpha”, which is provided along with the dataset.

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Naming conventions: These cross section diagram layers are named with the lowercase “xsc” in the filename to differentiate them from the cross section location line map layer,discussed previously, which has “XSC” in the name in all-caps.

A more detailed step-by-step account of the process used to scale and build the cross section diagram is given in Appendix V: Instructions for Digitizing Cross Sections and

Stratigraphic Columns.

III. Feature Attribution and Associated Symbols

Map features are first drawn and “cleaned” by creating and running topology to check for digitizing errors such as line intersections, overlaps, and dangles, before adding attributes. Certain features like faults and geologic contacts, and contact lines and polygons, must be collected in the proper sequence because of shared locations. Refer to the detailed instructions in Appendix IV and to Figure 7, the Geologic Map Digitizing

and Topology Process Flowchart for a step-by-step guide to this cyclic process.

A crucial element in the processing and representation of abstracted map data through a GIS is the assignment of attributes to spatial features. Attributes function directly when querying features and indirectly by controlling cartographic symbol styles in electronic and hardcopy maps. See the GIS layer descriptions (GIS data dictionary) in Appendix Ifor a full list of attribute fields, data types, and acceptable value ranges.

A. Polygon Features

Polygons are labeled in the maps with the “Unit_Abbrv” field. This field contains the letter symbols used to represent the geologic units, i.e., “Do” for Devonian Oriskany, or “Sto” for Silurian Tonoloway Limestone, and so on. Unit Abbreviation Symbols and descriptions of geologic units for each quadrangle can be found in the Open-File Report of Investigations document that usually accompanies each Open-File Geological Map. Attempts have been made to use a consistent and unique unit abbreviation symbol for each unit across all quadrangles mapped digitally. A Geologic Unit Information table and Source Map Information table will be compiled for use in all maps from these unit descriptions and abbreviations used, that can be joined to the “Unit_Abbrv” field.The geologic unit polygons layer contains a special label field, “GeoAge_Label” to properly label the units on any maps produced, using the True-Type Font “geoageFullAlpha”, which is provided along with the dataset.

B. Line Features

Many line feature layers have several fields related to confidence and symbol style. These fields are short integer with, in the case of Confidence, increasing values indicating greater uncertainty, e.g., 1 = certain, 2 = approximately located, 3 = inferred, 4 = inferred, queried. The Type field in the contact line feature class is used to distinguish quadrangle or state boundary from contact. Symbol field values are combined from one or more other fields. For example, the contact line Symbol field may have a value of 12, indicating Type = 1 (contact) and Confidence = 2 (approximately located). Line features

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are symbolized according to the confidence associated with the original geologic map features. Solid lines indicate a confidence level of “certain,” while dashed, dotted, and question mark (‘?’) symbols indicate “approximately located,” “inferred,” and “inferred, queried,” respectively.

C. Point Features

Bedding Orientation Points are sometimes identified using arbitrarily assigned station numbers, that can be matched to data recorded in a field journal or exported from a handheld device. Rock type and bedding orientation measurements are recorded by field geologists at the point locations. The horizontal compass direction, or strike, of the rock layer is recorded as, or converted to, an Azimuth value, which is an absolute value between 0 and 360 degrees vs. Strike, which needs a directional identifier such as “N 20deg.W”. For example the “N 20deg W” Strike would be an Azimuth of 340 degrees. The Azimuth value is unambiguous, and is used in the advanced symbol properties of ArcMap to rotate the bedding symbol on the map.

Dip_Angle, a measure of the rock’s tilt downward and perpendicular to strike, isdisplayed in the map as a feature label, using the Dip_Direct field as a rotation field in advanced label placement properties to correctly place the labels around the bedding symbol. The Dip_Direct field should always be calculated from the Azimuth field values using the Field Calculator tool in the attribute table, and applying the formula “Dip_Direct = Azimuth + 90”. Any resulting values that are over 360 degrees should be adjusted by subtracting 360 from the value to get the correct azimuth-style value for dip direction. No Azimuth or Dip_Direct values can exceed 360 degrees. No Dip_Anglevalues can exceed 90 degrees. No NULL values are allowed in any fields. Zero (“0”) is a real value for horizontal (flat-lying) bedding orientations ( for Azimuth, Dip_Angle, and Dip_Direct fields).

The Symbol field contains one of five values determining how the bedding orientation symbol will appear on the map: 1 = Inclined, 2 = Horizontal, 3 = Vertical, 4 = Overturned, and 5 = Foliation. See the legend in Appendix II to see what these symbols look like.

The ArcMap “Geology 24K” symbol set contains icons for the above bedding orientations used in the geologic quadrangles. This extra symbol palette can be accessed in the “Symbol Selector” dialog box by clicking on the “More Symbols” button and choosing “Geology 24K” from the list. The size of the point symbols can be adjusted as large as needed for clarity.

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IV. EDGEMATCHING

Geologic features are usually mapped and digitized in discrete quadrangles. Polygons and linear geological features should, however, match seamlessly across quad boundaries. The 1:24,000-scale geological GIS files will eventually cover all of West Virginia, further emphasizing the need for seamless integration of all quadrangles. The National Parks Service has also specifically requested for this project that “All maps seamlessly edge match with each other and with other mapping on adjacent quadrangles.”

Line and polygon locations and attributes should match across the quadrangle boundaries. Line locations may be adjusted slightly on one or both quadrangles to achieve a match. Adjacent quadrangle maps should be checked before polygons are generated to simplify this process, but this is not always possible. If geologic unit polygons already exist, Topology Editing Tools should definitely be used in order to edit co-incident features such as contact lines, polygon boundaries and fault lines, to maintain correct feature topology and co-incidence and not create new errors.

In some cases, multiple geological formations have been separated by geologists in one quadrangle but mapped in adjacent quads as a single, combined unit. Figure 6 is an example of this. The same polygon color can be used for both the combined and separated formations, thus simplifying the visual aspect of the map while preserving geological detail in the GIS. The quadrangle edge serves as the boundary between the differently-mapped geological contact units in cases such as this.

Figure 6: Combined Sto, Swc units (center orange unit, lower, labeled “Stowc”) and separated Sto and Swc formation polygons (center yellow and orange units, upper) at quadrangle boundary.

Stowc

Sto

Swc

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V. QUALITY CONTROL

The following quality control measures are undertaken during the conversion process:

Checklist: The Geologic 7.5’ Quad Digitizing and the QA/QC Checklists found in Appendix III should be completed for each digitized quadrangle or park unit, and submitted along with the digital geologic map files to WVGES for the internal review process, prior to external review and publication. The checklists are designed to be a comprehensive review of the following:

Positional Accuracy: Verify that scanned geological maps were georeferenced correctly with correct quadrangle index layer. Verify the quad boundary layer didn’t get accidentally moved during digitizing process. Verify correct corner tics were used for NAD83.

Topology & Direction: Linear and polygon geometric errors (e.g., undershoots, dangles, missing linework, intersections, etc.) and polygon label errors (e.g., misspelled, duplicate or missing labels) were checked and fixed. Final topology validated and error-free. Coincident features were edited with topological rules to ensure shared features were edited together. Line directions (e.g., for fault and fold symbology) were checked and fixed. Bedding point locations with missing, incomplete, or erroneous data were checked and fixed, and if necessary, deleted from the dataset. Points symbolized and checked they rotate correctly, if not, fixed.

Content: Digitized layers were checked against scanned source material. Errors, omissions, and inconsistencies may be noted in the original open-file texts and paper maps; edits to the final digital GIS layers and map layouts should be made to ensure that the digitized version of the map is as accurate, up-to-date, consistent, and complete as possible. Any errors fixed during the GIS process, or any other deviations required from the original map should be noted on the Geologic 7.5’ Quad Digitizing Checklist found in Appendix III, to document all changes made from the author’s original work, subject to the author’s final approval. Digitized map products will be reviewed by their authors and any errors or issues found, documented and fixed will be approved for the final version.

Edgematch: All maps produced should seamlessly match both linework and attributes along the quadrangle edges to each other, and to the best extent possible, to any previously produced maps.

Database Integration: Verify all attribute fields in each map layer (field names,field types and lengths) and attribute values are consistent with the WVGES data model, to assist in merging/appending of quads together in the future, and minimize the time needed to publish the final map. Filenames for map layers must also be consistent with WVGES naming conventions and data model. Attributes of features should be double-checked for correctness and completeness.

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Appendices

Appendix I: GIS map layer descriptions (Data Dictionary/Data Model)

The various data layers of the geologic map GIS are described below. The Brandywine quadrangle is used as an example here in place of <Quadname>.

Filenames are composed of the whole quad name plus a three-character layer descriptor: <Quadname>_XXX Use the underscore to separate parts of filename (NO spaces)

Field Names should be spelled exactly as shown and given field type shown in italics: Attribute Field Names : Field types (number indicates width of field): List of allowed attribute codes in field and a short description of each

A. Features with polygon and line topology:

Layer: Geological Formation Contacts, Lines: <Quadname>_CNTLayer file name: Brandywine_CNTLayer type: PolylineLine attribute fields: Type : short integer

-99 = Quadrangle boundary-88 = State or County boundary

1 = Contact Confidence : short integer 1 = Certain (Solid line) 2 = Approximately located (Dashed line) 3 = Inferred (Dotted line) 4 = Inferred, Queried (Dotted line with question marks) Symbol : short integer -99 = Quadrangle boundary

-88 = State or County boundary 11 = Contact, Certain 12 = Contact, Approximately located 13 = Contact, Inferred 14 = Contact, Inferred, Queried

Unit_Abbrv : text 102 - 10 character unit abbreviation used on map (For thin (only a line-width at 1:24,000 scale) marker beds, coal seams, etc that are also

geologic unit contacts. Thicker than line-width units should be polygons. Non-contact forming units should be in the COAL layer)

Layer: Geological Formation Contacts, Polygons: <Quadname>_CNT_poly Layer file name: Brandywine_CNT_poly Layer type: PolygonPolygon attribute fields:

Unit_Abbrv : text 10 2 - 10 character unit abbreviation used on map

GeoAge_Label : text 102 - 10 character unit abbreviation used on map, utilizes the geoageFullAlpha font (provided with the dataset) to properly symbolize geologic time period special characters (e.g., _,* symbols used for Cambrian, Pennsylvanian, etc).

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Layer: Quaternary Alluvium Contacts, Lines: <Quadname>_QAL (For maps showing only simplified Quaternary alluvium units, and with concealed bedrock contacts drawn in under the Qal. If no concealed bedrock contacts are shown, include Qal units in with the CNT line and polygon layers. For surficial deposits mapped in more detail, use SRF line and polygon layers.)Layer file name: Brandywine_QAL Layer type: PolylineLine attribute fields:

Type : short integer-99 = Quadrangle boundary-88 = State or County boundary

1 = ContactConfidence : short integer

1 = Certain (Solid line) 2 = Approximately located (Dashed line) 3 = Inferred (Dotted line) 4 = Inferred, Queried (Dotted line with question marks)

Symbol : short integer -99 = Quadrangle boundary

-88 = State or County boundary 11 = Contact, Certain 12 = Contact, Approximately located 13 = Contact, Inferred 14 = Contact, Inferred, Queried

Layer: Quaternary Alluvium Contacts, Polygons: <Quadname>_QAL_polyLayer file name: Brandywine_QAL_poly Layer type: PolygonPolygon attribute fields:

Unit_Abbrv : text 10 2 - 10 character unit abbreviation used on map

Layer: Surficial Geology Formation Contacts, Lines: <Quadname>_SRF ** (For detailed surficial geology usually shown on separate map sheet) Layer file name: Brandywine_SRFLayer type: PolylineLine attribute fields: **Kite(2003) Data Model to be used on NPS Surficial Maps

Type : short integer -99 = Quadrangle boundary-88 = State or County boundary

1 = ContactConfidence : short integer

1 = Certain (Solid line) 2 = Approximately located (Dashed line) 3 = Inferred (Dotted line) 4 = Inferred, Queried (Dotted line with question marks)

Symbol : short integer -99 = Quadrangle boundary

-88 = State or County boundary 11 = Contact, Certain 12 = Contact, Approximately located 13 = Contact, Inferred 14 = Contact, Inferred, Queried

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Layer: Surficial Geology Contacts, Polygons: <Quadname>_SRF_poly **Layer file name: Brandywine_SRF_poly Layer type: PolygonPolygon attribute fields: **Kite(2003) Data Model to be used on NPS Surficial Maps

Unit_Abbrv : text 10 1 - 10 character unit abbreviation used on map

B. Features with line topology

Layer: Faults: <Quadname>_FLT Layer file name: Brandywine_FLTLayer type: PolylineLine attribute fields:

Name : text 25 (For faults named on map)Type : short integer

1 = Normal2 = Thrust (also called Reverse)

3 = Strike Slip (also called Lateral)Confidence : short integer

1 = Certain2 = Approximately located3 = Inferred4 = Inferred, Queried

Symbol : short integer11 = Normal, Certain12 = Normal, Approximately located13 = Normal, Inferred14 = Normal, Inferred, Queried21 = Thrust, Certain22 = Thrust, Approximately located23 = Thrust, Inferred24 = Thrust, Inferred, Queried31 = Srike-slip, Certainetc

Fault_Type : text 20 (type and direction of movement)Normal_up_NE (or NW, S etc.) Reverse_SE (or NW, W etc.)

Strike Slip RL (right-lateral strike slip (direction of top arrow)) Strike Slip LL (left-lateral strike slip (direction of top arrow))

Layer: Structural Fold Axes: <Quadname>_STRLayer file name: Brandywine_STRLayer type: PolylineLine attribute fields:

Name : text 50 (For major folds named on map) Type : short integer

1 = Anticline 2 = Syncline 3 = Anticline, Overturned 4 = Syncline, Overturned

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Fold_Type : text 25 (fold types as text values and overturned direction) Anticline

Syncline Anticline, ot,e (or w, sw, etc) Syncline, ot,e (or w, sw, etc)

Confidence : short integer 1 = Certain 2 = Approximately located 3 = Inferred 4 = Inferred, Queried

Plunge : short integer 0 = Non-Plunging 1 = Plunging

Symbol : short integer 110 = Anticline, Certain 120 = Anticline, Approximately located 130 = Anticline, Inferred 140 = Anticline, Inferred, Queried 111 = Plunging Anticline, Certain 121 = Plunging Anticline, Approximately located 131 = Plunging Anticline, Inferred 141 = Plunging Anticline, Inferred, Queried 210 = Syncline, Certain 220 = Syncline, Approximately located 230 = Syncline, Inferred 240 = Syncline, Inferred, Queried 211 = Plunging Syncline, Certain 221 = Plunging Syncline, Approximately located 231 = Plunging Syncline, Inferred 241 = Plunging Syncline, Inferred, Queried 310 = Overturned Anticline, Certain 320 = Overturned Anticline, Approximately located

330 = Overturned Anticline, Inferred340 = Overturned Anticline, Inferred, Queried

410 = Overturned Syncline, Certain 420 = Overturned Syncline, Approximately located

430 = Overturned Syncline, Inferred440 = Overturned Syncline, Inferred, Queriedetc.

Layer: Igneous Intrusive Features: <Quadname>_ILNLayer file name: Brandywine_ILNLayer type: PolylineLine attribute fields: Confidence : short integer 1 = Certain 2 = Approximately located 3 = Inferred 4 = Inferred, Queried

Unit_Abbrv : text 10 2 - 10 character unit abbreviation used on map

Rock_Type : text 25 Rock type (e.g., andesite, basalt, pyroxene, etc.)

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Layer: Non-Contact-Forming Marker Beds/Coals: <Quadname>_COALLayer file name: Brandywine_COALLayer type: PolylineLine attribute fields:

Name : text 50 (Full coal or sandstone bed name)Type : short integer

1 = Coal 2 = Other marker bed type (Sandstone, Fireclay, Tuff, etc)

Confidence : short integer 1 = Certain 2 = Approximately located 3 = Inferred

4 = Inferred, Queried Symbol : short integer

11 = Coal, Certain12 = Coal, Approximately located13 = Coal, Inferred14 = Coal, Inferred, Queried21 = Other marker bed type, Certain22 = Other marker bed type, Approximately located23 = Other marker bed type, Inferred24 = Other marker bed type, Inferred, Queried

Unit_Abbrv : text 102 - 10 character unit abbreviation used on map (use official WVGES-CBMP names and abbreviations for all COALS—see “CBMP Coal Abbreviation Codes” table)(For thin (only a line-width at 1:24,000 scale) marker beds, coal seams, etc that are NOTgeologic unit contacts. Thicker than line-width units should be polygons. Contact forming units should be in the CNT layer)

Layer: Coal/Sandstone Structural Contours: <Quadname>_<CoalName>_STC Layer file name: Brandywine_No5Block_STCLayer type: PolylineLine attribute fields:

Elev : long integer (to leave enough spaces for negative numbers below sea level) Elevation of contour line

Confidence : short integer 1 = Certain 2 = Approximately located 3 = Inferred

4 = Inferred, Queried Symbol : short integer

1 = Contour Line, Certain2 = Contour Line, Approximately located3 = Contour Line, Inferred4 = Contour Line, Inferred, Queried

Unit_Abbrv : text 10 2 - 10 character unit abbreviation used on map

Layer: Cross Section Location Line: <Quadname>_XSC Layer file name: Brandywine_XSCLayer type: PolylineLine attribute fields:

Name : text 25 (<Quadname> A-A’, etc. For example: Brandywine A-A’)

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C. Feature classes with line and polygon topology for digitized cross sections

Layer: Cross Section Frame Lines: <Quadname>_xsc_frame Layer file name: Brandywine_xsc_frameLayer type: PolylineLine attribute fields:

Elev : long integer (to leave enough spaces for negative numbers below sea level)-9999 = Frame axis (Vertical and Horizontal)Elevation of tic marks on vertical axes (example: 2000, 0, -2000)

Layer: Cross Section Contacts & Fault Lines: <Quadname>_xsc_cnt Layer file name: Brandywine_xsc_cnt Layer type: PolylineLine attribute fields:

Type : short integer 1 = Contact 2 = Fault

Confidence : short integer 1 = Certain 2 = Approximately located 3 = Inferred

4 = Inferred, Queried Symbol : short integer

11 = Contact, Certain12 = Contact, Approximately located13 = Contact, Inferred14 = Contact, Inferred, Queried21 = Fault, Certain22 = Fault, Approximately located23 = Fault, Inferred24 = Fault, Inferred, Queried

Unit_Abbrv : text 10 2 - 10 character unit abbreviation used on map

(For thin (only a line-width at 1:24,000 scale) marker beds, coal seams, etc that are ALSO geologic unit contacts. Thicker than line-width units should be polygons. Non-contact forming units should be in the xsc_coal layer)

Layer: Cross Section Marker Beds/Coals: <Quadname>_xsc_coal Layer file name: Brandywine_xsc_coalLayer type: PolylineLine attribute fields:

Name : text 50 (Full coal or sandstone bed name)Type : short integer

1 = Coal 2 = Other marker bed type (Sandstone, Fireclay, etc)

Confidence : short integer 1 = Certain 2 = Approximately located 3 = Inferred

4 = Inferred, Queried Symbol : short integer

11 = Coal, Certain12 = Coal, Approximately located13 = Coal, Inferred

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14 = Coal, Inferred, Queried21 = Other marker bed type, Certain22 = Other marker bed type, Approximately located23 = Other marker bed type, Inferred24 = Other marker bed type, Inferred, Queried

Unit_Abbrv : text 10 2 - 10 character unit abbreviation used on map (use official WVGES-CBMP coal abbrvs)

(For thin (only a line-width at 1:24,000 scale) marker beds, coal seams, etc that are NOTgeologic unit contacts. Thicker than line-width units should be polygons. Contact forming units should be in the xsc_cnt layer)

Layer: Cross Section Contacts Polygons: <Quadname>_xsc_cnt_poly Layer file name: Brandywine_xsc_cnt_poly Layer type: Polygon Polygon attribute fields:

Unit_Abbrv : text 10 2 - 10 character unit abbreviation used on map

GeoAge_Label : text 102 - 10 character unit abbreviation used on map, utilizes the geoageFullAlpha font (provided with the dataset) to properly symbolize geologic time period special characters (e.g., _,* symbols used for Cambrian, Pennsylvanian, etc).

D. Features with point topology

Layer: Bedding Orientations (Strike and Dip) : <Quadname>_BEDLayer file name: Brandywine_BEDLayer type: Point Point attribute fields: Station : short integer (Station ID number, join field for Excel, not present in all quads) Azimuth : short integer (0 – 360 degree value)

Dip_Angle : short integer (0 – 90 degree value) (point label field, rotated by Dip_Direct field) Dip_Direct : short integer (0 – 360 degree value) (Dip Direction = Azimuth + 90)Adjust any >360

Symbol : short integer (symbol is rotated by Azimuth field) 1 = Inclined 2 = Horizontal 3 = Vertical 4 = Overturned

5 = Foliation

Layer: Data Point Locations for Control Point/Inset Maps : <Quadname>_PNTLayer file name: Brandywine_PNT Layer type: Point Point attribute fields: Not standardized at this time This layer is for various point data used to create the map, such as: non-bedding field observation points from GPS, drill holes, gas well point locations, county geologic report points, points containing confidential data, and the like, purely for the purpose of including a control point inset map on the final published map layout. Layer: Cross Section Point Labels : <Quadname>_xsc_pointlabelsLayer file name: Brandywine_xsc_pointlabels Layer type: Point Point attribute fields:

Name : text 50 (for major structural, topographic and cultural features that “hover” over the cross section on the map layout)

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Appendix II. Cartographic symbol legend

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Appendix III. Geologic7.5’ Quad Digitizing & QA/QC Checklists

(Excel and Adobe Pdf format files for printing and actual use are provided on the DVD)

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Appendix IV: The Polygon Building and Topology Process

After linework is completed on a layer (such as geologic or surficial contacts that will be used to make the geologic unit polygons), any bookmarks/questions from digitizing are answered, and lines are attributed, it is time to make polygons and topology. Polygons are ALWAYS GENERATED FROM LINES!!!!

1) CREATE A

PERSONAL

GEODATABASE

If not working within a personal geodatabasealready, create a personal geodatabase (GDB for short) in ArcCatalog and import the geologic or surficial contacts line shapefile and the quadrangle boundary shapefile into it. In ArcCatalog, (shown right)Right click on the directory folder icon in the left pane to create a new GDB in that folder: click on New—Personal Geodatabase then name the GDB with the quadrangle name (In this example we are using the Headsville quadrangle surficial geology layers so the GDB will be called “Headsville.mdb”.)

2.) CREATE FEATURE DATASET

Right click on the new GDB (shown left) and choose New—Feature Dataset, give it the quad name, click “Next”, then choose the correct XY coordinate system that you are using for your dataset, (E.g. UTM, NAD 27 or 83, Zone 17) click “Next” for all other options to create the Feature Dataset.

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3.) ADD SHAPEFILES OR FEATURE CLASSES TO THE DATASET

Right click on the Dataset you created, and click Import –Feature Class (single).(Follow the red arrows on the screenshot to the right.)

In the Dialog box that comes up, choose the contact line feature class layer that you have digitized as the “Input Features”, choose the GDB you just created as the “Output Location”, and give the “Output Feature Class” the correct layer name (Follow the project data model naming conventions <Quadrangle>_XXX at all times. In this example the Feature Class will be named Headsville_SRF). Ignore the “Expression”and “Field Map” options.

Repeat the above step to import the Quadrangle polygon shapefile for the specific quadrangle of your dataset into the GDB.

From now on you will be working in the geodatabase. The old contact line shapefile can now be a backup copy of your data, if needed. Otherwise, once final line and polygon feature class layers are created, the old shapefile versions should be deleted.

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4.) GENERATE POLYGON LAYER

Right click on the Dataset icon (the level above the Feature Classes in ArcCatalog,shown above) and choose New—Polygon Feature Class From Lines. Give this layer the correct layer name (e.g. Headsville _SRF_poly) in the box that comes up. Leave default cluster tolerance, and select BOTH the Quad boundary and Contact line layer as “Feature classes that will contribute lines”, and click “OK”.

5.) CREATE TOPOLOGY and ADD RULES

Right click on the Dataset icon in ArcCatalog and choose New—Topology. This opens up the Topology wizard that will guide you through creating and validating topology for the line/polygon dataset. Click “Next” on the first and second screens of the wizard. (use default Topology

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name of <Quadrangle_Topology> , and default cluster tolerance).

Click to select all the feature classes that will participate in the topology. You will need at least the contact lines layer and the quad boundary polygon to create contact polys.Click “Next” for the screen that ranks the feature classes, all should have a rank of 1.

On the next screen, click “Add Rule” to add the following Topology Rules:

Line-To-Polygon Topology Rules:

Headsville_SRF - Must Not Overlap

Headsville_SRF - Must Not Intersect

Headsville_SRF - Must Not Self-Overlap

Headsville_SRF - Must Not Self-Intersect

Headsville_SRF - Must Be Covered By Boundary Of - Headsville_SRF_poly

Headsville_SRF_poly - Must Not Overlap

Headsville_SRF_poly - Must Not Have Gaps

Headsville_SRF_poly - Boundary Must Be Covered By - Headsville_SRF

Headsville_SRF - Must Not Have Dangles

Once all the rules are added, save the rule set. Next time you create polygons and run topology, click “Load Rules” to use this saved set of rules again. You will have to do an extra step here of mapping the layers from the saved rule set to your target data layers,then proceed as usual with the rest of the steps.

Click “Next” and once you have confirmed everything in the next screen is correct, click “Finish”. Once the topology is created, click “Yes” to “Validate it Now”. Shown right is a validated topology in ArcCatalog with rule violations/errors for the first round of polygons in the Headsville dataset (in pink).

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6.) CHECK TOPOLOGY

Go to ArcMap, open a new map document, and add the Topologyyou created (e.g. Headsville_Topology) as a new layer to the map. (You will have to navigate to the new GDB for this layer, NOT YOUR OLD LINE LAYER Shapefile.) This will also bring in all related feature classes (e.g. the line, quad and polygon layers), so click “Yes” here:

Symbolize the layers as you wish (except topology layer) and save the new map document, e.g. “Headsville Topology.mxd”.

You may notice lots of pink errors in your dataset. Click the word “Editor” on the Editor Toolbar (shown below) and then click “Start Editing” from the dropdown list.

Open the Topology Toolbar if it is not already open (shown below). You can’t use the Topology Toolbar until you open an Edit session (ie, Start Editing).

Error Inspector Box

Click on the last icon on the right on the Topology Toolbar to open the “Error Inspector” box.

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Click the “Search Now” button (follow the arrows below) to bring up all the Topology errors in your dataset.

DO NOT PANIC! Most of the time one error will return multiple rule violations! So when you fix one thing, you may get rid of several errors as well.

The open Error Inspector Dialog box is shown above, along with the Validated Topology and the associated line and polygon datasets. Errors are shown in pink. You can sort the errors by type in the Error Inspector and also use the dropdown list to show only one type of error that you may be looking for. You can also mark exceptions to errors, and turn these on and off from view as well by checking the “Exceptions” box. When you select an error in the Error Inspector, it will turn black on the map instead of pink.

7.) FIX ERRORS

Don’t worry about editing or fixing any polygons for now, as this layer will be deleted and re-generated each time you run topology and fix line errors until there are none left.

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Fix all line errors: intersections, overlaps, self-intersects, dangles, and any “Must be covered by boundary of” errors where lines did not snap, or a line was not drawn on the map, and polygons didn’t form. Sometimes it will take some diligent searching to find where a polygon didn’t close and fix or add a missing line. It is not always obvious!

The main point here is to search out polygons that did not get formed, and fix the

line errors that caused this, so the poly will generate in the next round of the

cycle.

See “Hint” below for an easy way to fix dangles that are related to lines snapped to the quadrangle boundary. Don’t stress about quad boundary edge dangles, as these can easily be fixed all at once following the steps on the next page. DO fix dangles inside the quad that are clearly due to digitizing errors.

Read the topics on Fixing Topology errors in the Arc Help guide for how to use the Topology tools and fix various error types. There are Arc Tutorials available on the topic as well.

Once you have fixed an error, re-validate the topology by clicking on the “Validate Topology” icon(s) on the Topology Toolbar.

The Validate Topology Tools on the Topology Toolbar

This will check that the error is actually fixed and delete it from the error list. Any time a line or vertex is moved to fix a problem, it may create a new “Boundary Must Be Covered By” error in the polygon layer. When this happens, this type of error can be ignored in these early stages of the polygon-building cycle, because they will disappear when the polygon layer is deleted and regenerated from the corrected linework in the next part of the cycle.

Once you think you have fixed all errors and re-validated topology, save edits, close the map, go to Catalog. Delete the Topology layer in the GDB, then delete the polygon layer. Re-generate a new polygon layer from the corrected line layer, and create and validate a new topology (use the saved set of topology rules this time). See Figure 7,the Geologic Map Digitizing and Topology Process Flowchart, in this Appendix, for a visual guide to this cyclic process.

Repeat this cycle until NO errors remain but one “Must Not Have Gaps”, which is a pink line around the quadrangle boundary. This “Boundary Error” along the quadrangle boundary is an error which cannot be resolved due to the algorithms that the software uses to check for polygon gaps. Anything outside of the quadrangle boundary is considered a “gap”. This is the only acceptable error to have left in the datasets.

Once you have the final error-free line layer and a final polygon layer, with validated error-free topology, you may attribute the polygons!

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HINT: Fixing Quadrangle Boundary Line “Dangles/Boundary” Errors All At Once

Due to contact lines being “Snapped” to the edges of the quadrangle boundary line which is in a separate quadrangle polygon layer, there will be a lot of “Dangle” and related “Boundary Must Be Covered By” errors along the quadrangle edge in the first cycle of the Topology process. An easy way to fix these is shown below.

First, fix all errors within the body of the quadrangle, like intersections, overlaps, etc to minimize the number of errors to sort through in the Error Inspector and to ensure that no legitimate dangle errors from faulty digitizing are overlooked and left unfixed.

Then, in Error Inspector dialog box, sort the errors by type, by clicking on the “Rule Type” column heading, or choose “Boundary Must Be Covered By” as the Rule Type shown in the “Show” drop-down box at the top.

Select all the “Boundary Must Be Covered By” errors by shift-clicking them in the Error Inspector. Double check after they turn the black “selected” color, that only the lines along the quadrangle boundary have been selected, and NOT any lines within the body of the quad that may have resulted from fixing/moving lines and vertices. It is probably safest to do this in small batches as you are zoomed in to a quad edge, and pan around the quad boundary as you go.

Make sure the Editor Toolbar target is set to the “<Quadrangle>_XXX” contact line

layer and NOT any polygon layer. Using the “Fix Topology Error Tool” (shown below)on the selected quad boundary errors, right click, and select “Create Feature” on the hovering menu.

Fix Topology Error Tool

This will create a copy of the quadrangle boundary line into the contact line layer. The line can now be attributed with the quadrangle boundary attribute (-99 for Type and Symbol, 1 for Confidence). If you have previously attributed all the lines in the contact line layer, all you have to do now is use “Select by Attributes” tool to select all the new lines in the attribute table that have a <NULL> value for attributes (the selected features all turn blue) and use the “Field Calculator” feature on each attribute field to fill in all the attributes en masse for all the newly copied lines!

The “Dangle” line errors will automatically disappear the next time you Validate Topology. Voila!

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Fixing Lines & Polygons After Polygons and Topology Have Already

Been Created:

If you discover some missing lines and polygons that didn’t form after you have already run through the Topology cycle several times and created and attributed the final polygon layer, all is not lost; these problems can still be fixed. While it is much easier to catch and fix this sort of thing during the initial line drawing stages, there is a set of tools and techniques that exist to take care of these problems, though they are more complicated to use, and require a certain amount of proficiency with ArcMap editing and topology tools:

1) First, open the contact lines and its related polygon and topology layers in ArcMap and open an edit session. Open the Editor and Topology toolbars.

2) Find an area with a missing line or unclosed area that didn’t form a polygon that needs to be fixed. Make sure the only selectable layer on the “Selection” tab at the base of the left window pane of ArcMap in the Table Of Contents, or TOC, is the line

layer you are going to edit.

3) Make sure the editing target in the Editor Toolbar is set to the Line layer. Use the Create Feature tool (looks like a little pencil, shown below) to draw in the missing line. Be sure that snapping is set appropriately for your dataset before you do this or you will just create more problems. Snap the new line segment to appropriate locations on the existing lines, for example line “Ends” only. If there are no line ends nearby to snap the new feature to, you will first need to create some using the “Split” tool from the Editor Toolbar to split existing line features. Be sure NOT to move any lines or vertices of existing features when you do this! (because this will create line/polygon boundary errors that are much harder to fix)

Create Feature Tool Split Line Tool Attribute Editing Box

4) While the new line is still selected, give it the appropriate attributes in the Attribute Editing Box from the Editor Toolbar (shown above).

5) While the new line is still selected, switch the target in Editor Toolbar to the related Polygon layer.

6) While the new line is still selected, on the Topology toolbar, click the “Construct Features” tool (looks like a square with a wrench in it, shown below) and on the box

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that comes up, choose the “Split existing features in target layer using selection” option, and click OK. (Default cluster tolerance should be fine). This creates a new polygon feature by using the new line to split the existing polygon into two new ones.

Construct Features Tool

7) Click on “Clear Selected Features” (important!)

8) Switch the only selectable layer now to the polygon layer on the “Selection” Tab in the ArcMap TOC.

9) Using Edit Tool from Editor Toolbar (looks like small black arrow next to the word “Editor”) select the newly created polygon. Give it attributes in the Attribute Editing Box (last icon on the right side of the Editor Toolbar).

Edit Tool Attribute Editing Box

10) Click on “Clear Selected Features” again.

11) Use the “Validate Topology in the Current Extent” tool (center one of the Topology Validating tools on Topology toolbar) to make sure everything is fixed and that you didn’t create any new errors! If you did, either fix them, or undo back to where you went wrong and try again!

Validate Current Extent Tool

HOORAY!! You have successfully fixed a polygon/line problem AND maintained good topology!!

(SEG: 5/5/2010)

37

Sometimes to fix an error, polygons must be merged:

1) After merging the polygons together, clear selected features and re-validate the topology. You will now have a pink topology error line where the line between the polygons used to be.

2) Use the “Fix Topology Error Tool” to click on the pink line, then right click and choose “Subtract” from the fix options on the hovering menu. This will split out and delete the old line segment that you don’t need anymore from the line layer. This is a much easier way to fix this than messing around with lines and moving vertices and potentially screwing up polygon boundaries and making more topology errors!

Fix Topology Error Tool

3) Re-validate the topology.

4) Edit any attributes that need fixed from the changed polygons.

5) Clear all selected features.

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39

Appendix V: Instructions for Digitizing Geologic Cross-Sections and Stratigraphic Columns**

1.) Scan original cross section or strat column in grayscale (or indexed color if in color) at 400 dpi. (If necessary, crop out cross section/column diagram from overall map layout in Adobe Photoshop and save as a separate .tif file. Maps, cross-sections or strat column images should all be georeferenced individually for best accuracy.)

2.) In Photoshop, perform any needed image sharpening, brightness/contrast, rotating, cropping, collar erasing, etc that may be needed before georeferencing. (Once an image has been georeferenced, it should not be edited again in Photoshop!)

3.) Measure cross-section location line, i.e., the A-A’ line, off of the geologic map to an accuracy of at least one-hundredth of an inch (0.01 inches) using a scale/drafting ruler, or measure the line off the scanned tif image of the map in Photoshop using the Measurement Tool (right click on the Eyedropper to find this tool. Look for “D1” along the toolbar at the top of the Photoshop window for the measurement). DO NOT measure the horizontal axis of the cross section itself, it MUST be the location line from the map.

4.) Write this measurement on the Geologic 7.5’ Quad Digitizing Checklist for your quadrangle in the cross-section checklist space provided, to keep a record of it.

5.) Convert the real-world paper measurement of the cross section location line into ArcMap inches by multiplying the measurement by 24,000. This will be the at-scale length of the cross section horizontal axis in ArcMap. Note this figure on the checklist. For example, a cross-section line

measuring 25.685 inches off the paper or in Photoshop X 24,000 will be 616,440 inches in ArcMap units.

6.) Examine the vertical axes of the cross section and note the vertical exaggeration which should be stated on the diagram. Measure the vertical axes and/or figure out how tall they should be on paper if they were drawn perfectly. Note the “perfect” figure (adjusted to correct errors) for the final height in inches of the vertical axes on the checklist. Do NOT just trust that axes are drawn perfectly, always scrutinize them for the following types of problems!: Note the vertical axis of this cross section example to the left has not

been completely drawn by the author. The axis line will need to be extended from where it ends by at least another 1000 feet to enclose the bottom of the diagram. Also the tic marks are not evenly spaced.

This will be corrected by building the “perfect” frame in Arc and warping the image to the frame.

40

Note the vertical axis of this cross section example to the left has not been completely drawn by the author. The vertical axis is also a non-standard vertical scale of 1:800. This will need re-scaled to 1:2000 by building the frame to the required final vertical depth, and warping the image to the frame in Arc, using whichever tics will match, such as the “2000” ft tic mark.

The Horizontal Axis has not been drawn at all. This will be corrected by building the frame in Arc.

The Vertical Axis lines were not drawn straight. This will be corrected by warping the image to the “perfect” frame in Arc.

The vertical axes of the cross section example to the left and right are from the same cross section diagram. The axis on the left side is drawn to 10,000 feet, but the right side axis is drawn to 12,000 feet. The diagram also extends below the 12,000 foot tic mark. This will be corrected by extending the frame downwards in Arc by the amount required, in this case another 2000 feet, (for a total depth of 14,000 ft) to enclose the whole diagram without cutting any of it off.

The vertical axis of the cross section example to the left shows the topographic profile at the top of the diagram exceeds the highest vertical tic of the axis. This will be corrected by extending the frame upwards in Arc by the amount required, in this case by another tic unit of 2000 feet, (for a final height of 4000 feet) to enclose the whole diagram without cutting any of it off.

The diagram will be georeferenced to the frame using the highest tic on the image, which in this case is the 2000 foot tic mark.

41

7.) Use the following tables and information to help you convert the vertical axis “perfect” total height in feet to inches on paper to ArcMap inches at 1:24,000 scale:

No Vertical Exaggeration = 1:1 or 1:2000 or 1 inch=2000 feet or 1:24000 scale

2X Vertical Exaggeration = 2:1 or 1:1000 or 1 inch = 1000 feet or 1:12000 scale

For example, for a cross section with no vertical exaggeration, at 1:2000 (which is the standard), and a vertical axis of 5000 total vertical feet (add up above and below sea level to get total feet!) should measure 2.5 in high on paper. Convert to ArcMap inches by multiplying by 24,000:

No Vertical Exaggeration (1:2000): 2X Vertical Exaggeration(1:1000):

4000 ft = 2 in high = 48,000 ArcMap inches 4500ft = 4.5in high = 108000 Arc inches 5000 ft = 2.5 in high = 60,000 ArcMap inches 5000ft = 5 in high = 120,000 Arc inches 6000 ft = 3 in high = 72,000 ArcMap inches 10000 ft = 5 in high = 120,000 ArcMap inches and so on. Be sure and note these figures on the Digitizing Checklist in the Cross Section area!

The vertical axis of the cross section example to the left appears to be perfect, but beware!! The labeled tics are all regularly spaced at 500 foot intervals until 4000 ft Below Sea Level (BSL). Then the last three unlabeled tics below 4000 are intervals of 100 ft each, for a total depth of 4300 ft! You will not be able to divide the vertical axis into equal segments in Arc without extending the frame to the next 500-foot increment, which is 4500 feet BSL.

This will be corrected by extending the frame (shown in RED, at left) downwards in Arc by the amount required, in this case another 2 units of 100 feet, extending the axis down to 4500 ft BSL. This will allow you to be able to divide the axis by equal segments in later steps of building the frame.

The diagram will be georeferenced to the frame using the lowest labeled tic on the image, which in this case is the 4000 foot tic mark. The diagram will be drawn as shown on the original image, if the author does not approve extending the lowermost unit to the bottom of the frame. In this case, the lowermost unit after the blue unit will be a polygon with a value of <blank>, so as not to imply the blue unit is twice as thick as it really is.

42

8.) In ArcCatalog, create shapefile or feature class layers for the cross section frame and contact layers (and coal layers if required), following the naming conventions and attribute fields in the data model. Naming Conventions: These cross section diagram layers have the lowercase “xsc” in the name to differentiate them from the cross section location line map layer with “XSC” in the name in all-caps. Give the xsc layers the same coordinate system as the parent geologic map.

9.) Open ArcMap and add the xsc layers and the scanned cross section image tif file to the digitized geologic map working document. You will draw the cross section at a short distance below the geologic quad map, so that they can be displayed in the same frame in ArcMap if needed. Be sure to allow enough space below the geologic map for the estimated height of the cross section, plus some white space. (**Stratigraphic columns should be drawn to the left side of the geologic map. Be sure to allow enough space for the width of the column, plus some white space.)

10.) Draw the horizontal axis for the cross section frame as follows: a. Left click to start drawing the line of the axis on the lower left side. b. Right click and choose “Direction/Length” from the floating menu. c. Enter “0” for Direction (Straight Horizontal), and “XXXXXX in” for “Length”, where XXXXXX

is the length of the horizontal axis converted to ArcMap inches that you calculated in Step 5. Using the previous example from Step 5, you would enter “616,440 in”. Make sure you enter the “in” for inches in the box, or it will default to whatever map units are set for the data frame, and you will get the wrong results!

d. Hit the Enter Key and the line will be drawn automatically to the exact specifications you entered. Hit the “F2” button to end the line.

11.) Draw the vertical axes for the cross section frame as follows:

a. Set “Snapping” to “End” for the xsc_frame layer. b. Start the line for the left side vertical axis line by snapping to the left end of the

horizontal axis line. c. Again right click, and choose “Direction/Length” from the floating menu.

RIGHT CLICK

43

d. Enter “90” for “Direction” (Straight Vertical), and “XXXXXX in” for “Length”, where XXXXXX is the length of the “perfect” vertical axis converted to ArcMap inches that you calculated in Step 7. Using an example from Step 7, you would enter “60,000 in” for a vertical axis of 5000 total feet that would measure 2.5 inches on paper.

e. Hit the Enter Key and the line will be drawn to the exact specifications. Hit “F2” button to end the line.

f. Repeat for right side vertical axis line. 12.) Select one of the vertical axis lines. Use the “Divide” function on the Editor Toolbar to divide the

vertical axis line into equal segments for the elevation tics. Check the “Delete the selected feature” box so the Divide Tool does not leave behind the original undivided line on top of the new, segmented ones. First figure out how many segments will be needed along the vertical axis (try to keep to units of 500 or 1000). For example:

13.) Repeat for the other vertical axis line.

14.) Attribute all frame axis lines drawn so far with the “-9999” attribute for “Elev” attribute field.

4000

3000

2000

1000

-1000

Sea Level

This vertical axis will have 5 equal segments along the axis line.

1

2

3

4

5

3. CCHECKTHIS BOX

44

15.) Digitize the Elevation Tics: Snapping to the ends of the vertical axis line segments, use the “Direction/Length” floating menu option to digitize short tics at the end of each segment, including the very top and bottom of the vertical axis, so it looks like the example in Step 12 above. Use a Direction of 180 for the tics on the left side of the frame, and 0 on the right side. Use a length of 150 for all tics (go with default ArcMap units, not inches this time). Hit “F2” to end each tic line.

16.) Attribute all elevation tic lines drawn along the vertical axes with the correct elevation attribute for each tic in the “Elev” attribute field. Include the minus sign for elevations below sea level. Use a value of “0” for Sea Level (This is a Long Integer type of field, so no text values are allowed).

17.) Save Edits and Stop Editing the cross section frame. In the Layer Properties box, turn labels “on” for this layer, using the “Elev” field. Now you should see the elevation of each tic mark displayed.

18.) Open the Georeferencing Toolbar, and choose the scanned cross section image as the target.

19.) Georeference the scanned cross section to the frame you just built, being careful to match the right vertical axis tics from the image to the correct (labeled) tics on the frame. Use 4 link points, the top and bottom of the vertical axis on both sides of the frame are the best points to use, but use whichever points seem best to get most accurate result. Make the image fit the frame. The frame is accurately measured, scaled, and mathematically generated; the paper diagram usually not so much.

20.) Digitize the cross section contact line (including topographic surface profile) and coal bed/marker bed line layers, snapping line “Ends” to the frame “Edge”. The contact line layer for cross sections contains the fault lines, regular contacts are Type=1, faults are Type=2 as per the data model. Coal and/or marker beds will have the Unit_Abbrv attribute per the data model.

21.) Use the same procedure for generating polygons as you do for the geologic map CNT and CNT_poly layers, except use <quad>_xsc_cnt and <quad>_xsc_frame layers to create the polys. (See Appendix IV for instructions on this process.)

22.) Create and Validate Topology for the cross section contact, frame and polygon layers. Once topology confirms that all polygons were created, attribute the polygons as per the data model. (You do not need to copy frame lines into the contact layer so ignore any errors related to frame boundary unless a polygon is not forming)

**Stratigraphic Columns: Use a similar procedure for creating the frame, georeferencing the

scanned image, and digitizing the stratigraphic columns, except it will be a vertically-oriented frame instead of a horizontal one, and will meet the specific vertical and horizontal dimensions of the strat column. Strat columns should be drawn to the left of the geologic map, instead of below it. Draw the weathering profile as if it were a topographic profile, but vertically. Use a point feature class layer for any fossil symbols or other point-type features that may be symbolized in the column. Use the USGS lithology polygon fill symbol palette to fill the unit polygons with the correct lithology symbol, rather than digitizing these details.