basic geodetics—what every gis user should know · magnetic north = differs from true north by...

Petroleum User Group Conference - 2013

Experts in Geomatics, Surveying, Positioning, Geospatial Data, and Mapping Sciences

Basic Geodetics – What Every GIS User Should Know

May 9, 2013

Steven Long Shell [email protected]

Michael Barnes Cain & Barnes LP [email protected]

mailto:[email protected]





Knowledge Data

Techniques

Tools

Zone of the Geodetic Quagmire

2 Source: Cain & Barnes LP


Knowledge

Basic Geography College, University Industry Training Learning & Development

Data

Techniques

Tools

Basic Geodetics

3


Geodetic Awareness of 5 Facts:

1. Geodetic Datum 2. Map Projection 3. Vertical Reference 4. Reference Orientation 5. Unit of Measurement

4

The least you need to know for Geospatial Data Management


Terrain

Geodetic Reference Surfaces

Geoid Equipotential surface which

approximates to MSL

Geoid Normal to Geoid

a b

Ellipsoid Surface where Computations are made

1/f = a/(a-b)

Ellipsoid

Normal to Ellipsoid

h H

N

N=h-H

5 Source: APSG

Petroleum User Group Conference - 2013 6

Examples of Geodetic Datums


How many geodetic datums? Review www.epsg-registry.org


Before GPS we had 150 years of geodetic surveying e.g. National Geodetic Survey of Nepal 1981-1983


Hierarchy of Mapping

Datum (ellipsoid & origin) is the Foundation

X,Y,Z Cartesian and Lat, Long, Ht

Equator

Zp

Xp Yp

P hp

Ellipsoid

λp Φp

stable Unstable w/o Datum

Projected CRS

is a derivative of the Datum (Geog CRS)

Easting, Northing, Elevation (above MSL)

9 Source: APSG


• Mercator • Transverse Mercator • Universal Transverse Mercator • Lambert Conformal Conic • Others less frequently: Stereographic,

Oblique Stereographic, Oblique Mercator, et. al.

10

What are the main map projections in use?


Local Kelly-Bushing, ground level, sea level, and assorted other local

references Geodetic Either directly or derived from Mean Sea Level at one or more

points at some epoch examples:

NGVD 29, NAVD 88, IGLD85, OSU91A, EGM96, EGM2008 Tidal Defined by direct observation of tidal variations over some

period of time at a specific location (or locations) examples: MSL, LAT, MLLW, MLW, MHW, MHHW

11

Vertical Reference: Height, elevation, vertical datum or what?


Potential for confusion with Local Vertical Datum

Source: UKOAA, now OGP


True North = Direction of the meridian through a point Magnetic North = Differs from True North by declination and varies with time Grid North = Differs from True North by convergence Gyro North = a measurement of True North by instrument Plant North = strictly a “local” non-georeferenced orientation

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Reference Orientations (5 kinds of north)


Reference Units: Biggest E&P Problem

US Survey Foot vs. International Foot

1 ftUS = 1.000002 ft (Intl), but this is still important for UTM, generating 30-60 foot errors, depending on latitude

Other Feet: Clarke’s Foot, Sears 1922, 2 for Benoit (both 1895), Gold Coast Ft., 4 Indian Ft. (1865, 1937, 1962 & 1975) and 2 British Feet (1865 & 1935), 2 meters: International Meter and German Legal Meter Other linear units include Chains, Links, and Yards

15

Units of Measurement (13 kinds of feet and 2 kinds of meters in use)


If you remember nothing else…..

• Latitudes and Longitudes are not unique unless qualified with datum name

• Projection Coordinates are not unique unless qualified with Projection name, Zone and Datum

• Heights are not unique unless qualified with Surface Reference (Vertical Datum)

• Orientations are not unique unless qualified with Heading Reference

• Units are not unique unless qualified with Unit Reference

16


Knowledge


Data Acquisition & Sourcing Processing & Integration Integrity & Handling Data basing & Retrieval

Techniques

Tools

Basic Geodetics

17


Corporate Geospatial Data Managed at global or business unit level

• Lease boundaries and licensed areas

• Seismic • Well data • Topographic and

bathymetry • Site survey and

environmental data • Infrastructure

(pipelines, platforms, cables..)

Company Propriety

data

• Seismic • Well database • Geologic data • High resolution

satellite imagery • Gravity and

magnetics

Third party

industry data

18


Past, Present, and Future Geodetic Integrity of Geospatial Data requires

Source: OGP GIGS


• Seismic surveys • Wells, surface and well bore

locations • Boundaries, lease and license areas

20

Fundamental Exploration Data Sets

Petroleum User Group Conference - 2013 21 Source: OGP

Petroleum User Group Conference - 2013 22 Source: OGP


80% + of all GG&E data

Mandatory Metadata

Easting and Northing, X and Y or Y and X ?

Units of Measure stated ? e.g. US Survey Foot International Foot

Meter, etc


NAD83 Seismic Survey incorrectly mapped as NAD27 – 400 feet of error as a block shift


Commercial Well Location Data

25

Source: APSG


Digital Land Grids (Cadastral)

26 Source: APSG


Area Discrepancy due to Incorrect Grid

27


Example Unit with Discrepancies Measured

28


Various State & Vendor Database Well Locations

29

Petroleum User Group Conference - 2013 30 Source: Conner

Petroleum User Group Conference - 2013 31 Source: Conner


Reasons for Mislocation of Wells

• Accuracy and reliability of original measurement systems and cartographic layers

• Miscalculations and poor QC • Error in transformation of Coordinate

Reference Systems • Transcription errors, data entered incorrectly • Transposing legacy data via new technologies • Inadequate documentation • Lack of industry standards for surveying and

mapping 32


Well Surface Locations are frequently wrong

33

Source: EnSoCo


Innovations in data use still requires sound geodetic and mapping principles


Time Lapse Plant refurbishment Iraq 7 months of overlay data

36

This image cannot currently be displayed.


Geo-Information Integration

1968 topo 2012 topo 2012 aerial

2010 DEM

1964 Surficial Geology

2006 photography


Seismic Project, Wyoming Twenty Four 2D Data Geodetic Parameters Options

• NAD27 • NAD83 • WGS84 • NAD27 / BLM 12N (ftUS) • NAD27 / BLM 13N (ftUS) • NAD27 / UTM zone 12N • NAD27 / UTM zone 13N • NAD27 / Wyoming West • NAD83 / BLM 12N (ftUS) • NAD83 / BLM 13N (ftUS) • NAD83 / UTM zone 12N • NAD83 / UTM zone 13N • NAD83 / Wyoming West • NAD83 / Wyoming West (ftUS) • NAD83(HARN) / UTM zone 12N • NAD83(HARN) / UTM zone 13N • NAD83(HARN) / Wyoming West

• NAD83(HARN) / Wyoming West (ftUS)

• NAD83(NSRS2007) / UTM zone 12N


• NAD83(NSRS2007) / Wyoming West

• NAD83(NSRS2007) / Wyoming West (ftUS)

• SPCS83 Wyoming West zone (meters)

• SPCS83 Wyoming West zone (US Survey feet) 38


CRS Metadata inadequate? What is mislocation risk?

• NAD27 • NAD83 • WGS84 • NAD27 / BLM 12N (ftUS) • NAD27 / BLM 13N (ftUS) • NAD27 / UTM zone 12N • NAD27 / UTM zone 13N • NAD27 / Wyoming West • NAD83 / BLM 12N (ftUS) • NAD83 / BLM 13N (ftUS) • NAD83 / UTM zone 12N • NAD83 / UTM zone 13N • NAD83 / Wyoming West • NAD83 / Wyoming West (ftUS) • NAD83(HARN) / UTM zone 12N • NAD83(HARN) / UTM zone 13N • NAD83(HARN) / Wyoming West

• NAD83(HARN) / Wyoming West (ftUS)



• NAD83(NSRS2007) / Wyoming West

• NAD83(NSRS2007) / Wyoming West (ftUS)

• SPCS83 Wyoming West zone (meters)

• SPCS83 Wyoming West zone (US Survey feet) 39


40

Same X,Y numbers used with different map projections NAD27 / Wyoming West or NAD83 / Wyoming West (ftUS)

Project Working West Wyoming

Data on Vacation Nebraska State Park


Geo-Information Integration?

41

Project GIS had 168 spatial layer


42

3D printing direct from GIS data


OGP ESPG Area Polygons reducing risk in handling of geodetic data

Source: OGP www.epsg-registry.org

2,900+ polygons available online


Example: Nigeria Onshore and EEZ

Rectangular Bounding Box – 11 geodetic datums – 13 Projected CRS* – 25 transformations

Geographic Area Polygon – 3 geodetic datums – 9 Projected CRS* – 13 transformations

* = datum + map projection

44


Knowledge Basic Geography College, University Industry Training Learning & Development


Techniques

Tools

GNSS (GPS) Positioning GIS Mapping Geoscience Software Engineering Software

Basic Geodetics

46

Source: Cain & Barnes LP


47 Source: Schostak


48


49


50


51


52


Geospatial Integrity Compliance Grade????



Techniques Standards & Practices Procedures & Workflows Quality Control Processes Continuous Improvement

Tools GNSS (GPS) Positioning GIS Mapping Geoscience Software Engineering Software

Basic Geodetics

54


Forensic Geodetics of Well Location (US GOM)

• Followed the data from G&G through Drilling Operations

• 486 documents with well location stated • Location stated as X and Y • Often stated as UTM 16N ftUS (aka BLM) • NAD 27 and NAD 83 both are relevant • 40% had no datum stated • Geoscience data handling in UTM 15

and 16 at various stages of process • Positioning difference is …. • Cost of the well is ……

55


NAD27 / UTM 15N vs. NAD83 / UTM 15N

56

Positioning difference is 656 feet Cost of Well US$ 85 million

∎


Transforming Coordinate Reference Systems Concatenated data operations are not trivial

57 Source: OGP EPSG Registry


Knowledge


Data

Techniques

Tools

Basic Geodetics

58


59


Demographics of Participants 2007-12


Relevant and Useful?


Data Tools

Knowledge Techniques

Zone of the Geodetics Quagmire

62


Agenda

• Defining a GIS Project

• Working in ArcMap

• Dissemination of Geo-Information

• Summary


Overview

Potential for geodetic integrity issues at all stages

GIS Project Setup

• What is my area of interest?

• How do I determine valid coordinate reference systems for my area of interest?

• What is the preferred coordinate reference system?

Working in ArcMap

• What happens when I import my data into ArcMap?

• What is the preferred transformation?

• What is the maximum error if incorrect transformation is selected?

Dissemination of Geo-Information

• Web Maps

• 3D Viewers

• Map Products


Agenda




• Summary


GIS Project Lifecycle

• Mandatory Coordinate Reference System (CRS) definition at project framing phase

• Ensure CRS validation for all subsurface applications

• Geomatics experts contacted at project start-up

Users should not make assumptions regarding CRS!

Source: McLay (2007)

Coordinate Reference Systems

(CRS)


Determining Coordinate Reference System

• OGP EPSG Area Polygons • Reduces risk in handling of geodetic data

Source: OGP http://info.ogp.org.uk/geodesy

2900+ polygons available online


OGP EPSG Area Polygons

• Download shapefile and load directly into ArcMap

Area of Interest


EPSG Geodetic Parameter Registry

• Structured dataset of Coordinate Reference Systems and Coordinate Transformations

• Options to “query by filter” or “retrieve by code”



EPSG Geodetic Parameter Registry (con’t)



Recommendations for CRS Selection

• Select an appropriate 2D geographic CRS (“datum”) which is in common use and has an accepted and well defined transformation to WGS 84

• Use an appropriate map projection that is in common use and has small distortions

• Consider existing legacy data

• Consider export of produced data / maps (i.e., regulatory reporting requirements)

Objective is to minimize geodetic risk

Obvious choice is not always “the best”


Agenda




• Summary


Geodetic Integrity and ArcGIS

• ArcMap has the ability to transform and re-project “on the fly”

• Can display data stored in one CRS as if it were in another, without altering the actual data

• Data frame’s CRS is defined by the first layer added to the data frame or by manually setting the CRS through the data frame properties

• But… there is no help to the user for the selection of the “preferred” transformation


Transformations – When To Use

• A transformation is required when changing coordinates from one CRS to another CRS (i.e., NAD27 to WGS 84)

Source CRS: NAD27

Target CRS: NAD27

Transform?

No Transformation

Required

Source CRS: NAD27

Target CRS: WGS 84

Transform?

Transformation Required


“Out-of-the-box” ArcGIS Transformation

No information about what are the differences between these transformations

Which one is the “preferred” transformation?


Custom Transformations

• Users have the ability to create custom transformations

Consult your local geodetic expert!


North American Preferred Transformations

NADCON - Conus

NTv2

NADCON - Alaska

Transformations from NAD27 to NAD83 (WGS 84)


Difference Between NAD27 and NAD83

Source: Wikipedia http://en.wikipedia.org


Agenda




• Summary


Web Maps

• Increasingly popular medium for displaying spatial information • Uses internet browser

Questions: 1) Do you know what coordinate reference

system is being used by the application?

2) Do you know the coordinate reference system of your input dataset?

3) Do you know what transformation is being used between the application and the input datum?

Beware of your input data properties and data operations performed by application

Source: ESRI http://www.arcgis.com/explorer


3D Viewers

• ArcGIS Explorer and Google Earth • Both allow input and display of GIS data • How is this data handled?

• Better integration with GIS data • Uses WGS 84 as CRS • Should only be used for small / medium scale

mapping • NADCON not supported

ArcGIS Explorer (Build 1750) Google Earth Pro (version 4.0.2737)

• Can consume shapefiles • Uses WGS 84 as CRS • Fitting of images of different types causes some of the

images to be distorted. How much? • Not advisable to do large scale digitization from images • Need to transform input datum into WGS 84


Map Products

• All maps should have the coordinate reference system as the

minimum; Name and EPSG code

• EPSG code is standard for oil and gas industry

• Example – EPSG Name: NAD27 / BLM 15N (ftUS) – EPSG Code: 32065

• ESRI names are not EPSG compliant • Look up codes in EPSG Geodetic Parameter Registry

– http://www.epsg-registry.org/


Summary

• Don’t make assumptions regarding coordinate reference systems

• Don’t assume the software sorts out your geodetic problems

• Make use of OGP EPSG polygons and EPSG geodetic parameter registry

• Seek advice from geodetic experts when in doubt


More than 460 experts in Geomatics, Geodetics, Surveying, Positioning and Navigation, Geospatial Data, and

Mapping Sciences

www.apsg.info

Apply online to join for professional development, technical education, business networking, and fellowship

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basic geodetics—what every gis user should know · magnetic north = differs from true north by...

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