Transcript PPT - Energistics

OGP Surveying and Positioning Committee
The EPSG Geodetic Parameter Dataset
Presentation to POSC SIG
July 21st, 2006
Aberdeen, UK
by
Palle J. Jensen, Maersk Oil and
Roger Lott (formerly BP)
International
Association of
Oil & Gas
Producers
The EPSG Geodetic Parameter Dataset
• OGP S&P / EPSG organisational background.
• Overview of the dataset.
• Relevance to regional and local E&P operations.
• Future plans for the dataset.
Organisational Background
Year
Event
1985
European Petroleum Survey Group formed
1992
EPSG makes the compilation of geodetic parameters publicly
available as the EPSG Geodetic Parameter Dataset.
• Coincident with the development of the POSC Epicentre
coordinate system model
2005
EPSG assimilated into the International Association of Oil and Gas
Producers (OGP) as the Surveying and Positioning Committee.
• OGP S&P continues to maintain the dataset.
• To retain consistency in “namespace”, the dataset will continue to
be known as the EPSG Geodetic Parameter Dataset.
OGP’s EPSG Geodetic Parameter Dataset
Overview
•
•
•
Database containing the definitions of coordinate reference systems from
around the world
– over 3000 coordinate reference systems (CRS)
– over 1200 transformations between CRSs
– mature data model
• relational data base implementation of ISO / OGC models
• evolved from POSC Epicentre
– periodically updated - typically twice per year
– Latest version 6.10 issued April 2006
Download from http://www.epsg.org
– MS Access 97 database (includes reporting)
– SQL scripts
– Guidance Notes (user manual and algorithm documentation)
De facto world standard
– E&P, GIS, remote sensing, telecomms (location based services)
EPSG Geodetic Parameter Data Set
Core Geodetic Parameters
Coordinate Reference System
Datum
Coordinate System
Ellipsoid
Axis / Axes
Prime Meridian
Coordinate Transformation
Source/Target CRS
Method
Parameters/values
Map Projection
(Projected CRS only)
Note: Transformations are not part of the CRS definition
EPSG Geodetic Parameter Data Set
User Interface
Relevance to regional and local E&P
Operations - Example
Ground Control Point
Origin of all recent seismic surveys and well locations in the block
Geographic Location
Latitude
Longitude
49º 08’ 29.46” North
56º 35’ 48.09” East
Is that good enough?
Is latitude and longitude all you need to
uniquely define a point on the ground?
Example –
Describing a geographic location
Control Point
Datum
Ellipsoid
Latitude
Longitude
WGS 84
WGS 84
49º 08’ 28”.64 N
56º 35’ 52”.30 E
Pulkovo 1942
Krassovsky 1940 49º 08’ 29”.46 N
56º 35’ 48”.09 E
Control Point
Datum
Ellipsoid
Map Projection Easting (m)
Northing (m)
WGS 84
WGS 84
UTM Zone 40
470 657.6
5 445 514.3
Pulkovo 1942
Krassovsky 1940 UTM Zone 40
470 584.7
5 443 266.0
Pulkovo 1942
Krassovsky 1940 Gauss-Kruger
470 582.9
5 443 406.6
Same point but coordinates differ (none of them are wrong)
• typically 50 to 500 metres, can be 1500m
Relevance to regional and local E&P
Operations - Example
•
•
•
•
•
Licence block boundary
coincides with international
boundary
Boundary agreement defines
location by geographical
coordinates
(latitude/longitude)
Datum not described
Allowance for locating wells
within 125m of boundary line
Different assumptions of
datum reference will cause
different locations of the
boundary by 300m
Relevance to regional and local E&P
Operations - Example
Actual vibrator
track
Mapped
seismic line
• Vintage seismic positioning
data used to plan up-hole
survey
• Differences of 385m
observed between mapped
and actual line location
• Error traced to incorrect
datum description in header
of data file
Example - Geodetic Transformations
•
Operate between CRSs - not part of CRS definition
•
There may be multiple transformations between any pair of CRSs
– e.g. EPSG Data Set contains 38 between ED50 and WGS 84
• differing area of applicability
– UK east of 6 deg W, Norway south of 62 deg N, etc.
• differing usage
– military, E&P
• differing legality
• differing accuracy
•
Using an incorrect variant might be significant
– computer applications that include transformation as part of CRS
definition can be dangerous
Future plans for the EPSG dataset
•
Work in progress to make the dataset contents available over the internet, with
interfaces:
• for machines (using Graphic Markup Language).
• for humans, through any web browser (web pages will have similar
content to that of existing MS Access browse forms and reports);
• pre-defined and user-defined queries.
– Project completion anticipated October 2006.
•
MS Access database and SQL scripts will continue to be available. Seek ISO
accreditation for the on-line data set.
•
No change to existing change request processing
– but new data will be made available as soon as processed.
•
No change to existing data access policy:
– data available at no charge to user.
EPSG Geodetic Parameter Dataset
Thank you