editing vector geodata - ?· topological relationships. ... the editor-layer manager and view...
Post on 27-Aug-2018
Embed Size (px)
Editing Vector Geodata
This booklet introduces techniques for creating, altering, and updating vectorgeospatial objects in the Editor in TNTmips and TNTedit. Vector objects thatyou make or import can contain point, line, and polygon elements in stricttopological relationships. Each element may have associated attributes and canbe connected with complex databases. The exercises in this booklet introduce youto the basic tools used with each element type for vector objects. The Editor alsohas tools for editing your CAD, raster, shape, database, and TIN geodata.
Prerequisite Skills This booklet assumes that you have completed the exercisesin the tutorials Displaying Geospatial Data and TNT Product Concepts. Thoseexercises introduce essential skills and basic techniques that are not coveredagain here. Please consult those booklets for any review you need.
Sample Data The exercises presented in this booklet use sample data that isdistributed with the TNT products. If you do not have access to a TNT productsDVD, you can download the data from MicroImages web site. In particular, thisbooklet uses objects in the NFRESGIS Project File in the EDITVECT data collection, andSTATES from the USA_STATE Project File and STATEPOP.DBF from the USA data collec-tion. Make a read-write copy of these files on your hard drive; you may encounterproblems if you work directly with the sample data on the DVD.
More Documentation This booklet is intended only as an introduction to vectorediting in TNTs Editor. Consult the Advanced Vector Editing tutorial bookletand numerous Technical Guides available on MicroImages web site for addi-tional information.
TNTmips Pro, TNTmips Basic, and TNTmips Free TNTmips comes in threeversions: TNTmips Pro, TNTmips Basic, and TNTmips Free. If you did notpurchase the professional version (which requires a software license key), you areusing TNTmips Free or TNTmips Basic, which limit the size of your projectmaterials. All exercises in this booklet can be completed in TNTmips Free,TNTmips Basic, and TNTmips using the sample geodata provided.
Merri P. Skrdla, Ph.D., 18 August 2013 MicroImages, Inc. 20002013
It may be difficult to identify the important points in some illustrations withouta color copy of this booklet. You can print or read this booklet in color fromMicroImages web site. The web site is also your source for the newesttutorial booklets on other topics. You can download an installation guide,sample data, and the latest version of TNTmips Free:
Before Getting Started
Editing Vector Geodata
TNTmips spatial data Editor (Main / Edit) offers aflexible, editing environment that can be used forsimple one-object tasks or complex multi-layer, multi-object manipulations. You can have one editableobject or a combination of read-only reference lay-ers with editable layers. You can have multiple typesof objects open for editing at the same time, stackedin any top-to-bottom order.
Editing operations apply to the currently activelayer. As you switch from layer to layer, the editingtools automatically change according to the datatype of the active layer (raster, vector, shape, CAD,or TIN).
You may see editing tools like those in TNTmips inother software products, but the important thingabout the TNTmips Editor is the way you can editmultiple geospatially related objects easily and in-tuitively. You can concurrently edit project materi-als of all types while TNTmips automatically retainsand reconciles their map registrations. This meansthat all the new objects you create can automaticallyderive their map registration from other layers, so allof your project materials have a correct geospatialrelationship.
Spatial Data Editing Overview
The exercises on pages 4-14 show how to create ageoreferenced vectorobject that containsdrainage line elementstraced from a topographicreference map. Thisactivity is often calledheads up digitizing. Pages15-17 introduce techniquesused in creating and editingother vector elements.Pages 18-22 deal withcreating and attachingattribute tables.
Newly created objects mayhave independently definedmap registration, or mapregistration derived fromanother layer in the editor.
A layer contains onegeospatial object: raster,vector, shape, CAD, TIN, ordatabase. TNT automati-cally reconciles the mapregistration and scale of alllayers.
One or more read-onlyreference layers may be
One marked elementmay be active forediting operations.
The active layer mayhave many elements.
One or moreelements maybe selected,or marked.
All map registrationis automaticallyreconciled andmaintained.
selected asthe active
Switch betweenone or more
Editing Vector Geodata
In the first set of exercises you will create a newvector object that contains georeferenced hydrol-
ogy line elements. You will use a referencelayer that is a georeferenced map scan withhydrology features, and trace over the hy-drology lines with the TNT editing tools.
Launch the TNT spatial data Editor by selecting Main/ Edit from the TNTmips menu bar. TNTmips opensthe Editor-Layer Manager and View windows. Mostmenus and icon buttons in the View window are thesame as those you are already familiar with in theMain / Display process. You can change a referencelayer into an editable layer using the Edit Ref-erence Layer icon on the Editor Layer Man-ager toolbar.
Adding a reference layer first provides the georefer-ence for the vector you are going to draw. You canchoose from among the reference layers or othereditable layers to provide the coordinate referencesystem for any new object. A new vector object willhave an implied georeference, which means that theobject coordinates will reflect the georeference co-ordinates.
Add a Reference Layer
Vocabulary: a referencelayer is a read-only layerused for visual and spatialreference. An editablelayer is a layer to whichyou can add and modifyelements.
The MAP_100 raster objectis a 333 x 269 8-bit color-mapped section of ascanned 1:100,000 papermap of Fresno, California.It is georeferenced toLatitude / Longitude mapcoordinates. Each rastercell represents approxi-mately 20 meters on theground. Since this rasteris georeferenced, anynew layers you createusing MAP_100 as areference layer canautomatically have thesame georeferenceattributes.
STEPS launch the Editor click the Add
ReferenceObjects icon button
select the MAP_100raster object from theNFRESGIS Project File inthe EDITVECT sample data
Edit Reference Layer
Add Reference Objects
Editing Vector Geodata
Create a Geospatial Vector ObjectUse the New Object Values dialog totell the Editor how your new vectorobject relates spatially to the MAP_100reference layer. The first panel lists yourchoices for georeference, and by de-fault, the selection highlight is on theFresno Map reference layer. Choosingthat item means that your new vector object willhave the same initial spatial extents, orientation, andmap registration as the MAP_100 reference layer.Automatic transfer of the coordinate reference sys-tem is one of the important benefits of using a refer-ence layer when you create new spatial objects: yournew object can take its coordinate reference systemfrom existing georeference, and thus it will automati-cally relate correctly to all of your other georefer-enced project materials.
Note that the New Object Values window also letsyou choose the topology level (polygonal, planar,or network) and whether to include an extents boxfor the vector object. You can also specify whetherthe vector coordinates are 2D-XY, 3D-XY (contourswith a single elevation value per line), or 3D-XYZ.For more information on vector topology, consultthe Vector Analysis Operations booklet.Although the georeference for the objectcannot later be changed in the Editor, theother parameters can be changed laterby selecting Object / Properties fromthe Editor Layer Manager.
STEPS click the Create
Object icon buttonand select Vector fromthe menu
click [OK] in the NewObject Values windowto copy georeferenceinformation from theselected MAP_100reference raster andcreate the new object
The New Object Values windowby default offers to creategeoreference control derivedfrom the MAP_100 referencelayer. Press the OK button toaccept the georeference andother parameters specified in thewindow.
Editing Vector Geodata
Change the Vector Line StyleThe Editor uses thin white lines as the default draw-ing style for vectors. For better visibility in thisexercise, change the line color to red or some otherbright color with a line thickness of 0.5 millimeters.
You can change line styles at any time during anediting session. You can save line style defi-nitions and use a single or multiple stylesagain and again. Since you are creating hy-drology line elements in this exercise, youwill eventually want them to display in blue.But since we are tracing over blue pixels in
the reference raster, the intermediate work will beeasier to see in red.
When changing line thickness or any other size pa-rameter in the TNT products, you want to changethe units first. If you change the numeric value first,it will automatically change to a new value to reflectthe newly selected units. The At Scale setting be-low the line width determines how the lines behavewhen you zoom in and out. A setting of None meansthat the line width does not change as you zoom inand out. The other two choices (User D