Opened 8 years ago

Closed 3 months ago

#4127 closed enhancement (wontfix)

[PATCH] Additional CRS definitions for ECW file ecw_cs.wkt

Reported by: armin Owned by: warmerdam
Priority: normal Milestone: closed_because_of_github_migration
Component: GDAL_Raster Version: unspecified
Severity: normal Keywords: ECW, CRS
Cc: dgrichard

Description

I have put together some additional definitions for various national European and pan-European projections, including datum definitions.

Attachments (2)

ecw_cs_eu.wkt (62.7 KB) - added by armin 8 years ago.
ecw_cs.wkt.patch (46.9 KB) - added by armin 8 years ago.

Download all attachments as: .zip

Change History (10)

Changed 8 years ago by armin

Attachment: ecw_cs_eu.wkt added

comment:1 Changed 8 years ago by yjacolin

Hello,

I see in your file this line (l. 88):

RGF93,GEOGCS["RGF93",DATUM["Reseau_Geodesique_Francais_1993",SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6171"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4171"]]

But RGF83 already exists, a little bit different:

RGF93,GEOGCS["FRANCE 1993",DATUM["RGF93",SPHEROID["GRS80",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["degree",0.0174532925199433]]

What this modification improve projection?

Regards,

Y.

comment:2 Changed 8 years ago by warmerdam

Cc: dgrichard added

comment:3 Changed 8 years ago by dgrichard

the data/ecw_cs.wkt of the trunk, one can be find another (third) RGF93 definition !

The addition seems to be correct, except for the AXIS definition part where IGN (the French NMA in charge of maintaining the CRS) uses the longitude, latitude order explicitly.

I would then suggest to keep the AXIS order explicit in the WKT definition.

Another point to agree upon is related with the AUTHORITY clause : currently, data/ecw_cs.wkt uses IGNF for this system, whilst the new definition uses EPSG. As the AUTHORITY clause allows an external authority to manage the definition of an entity, I would prefer keeping IGNF.

Therefore, I am more in favor of keeping the current record in the data/ecw_cs.wkt file with the appropriate changes on AUTHORITY for geogcs and datum clauses :

RGF93,GEOGCS["RESEAU GEODESIQUE FRANCAIS 1993",DATUM["RESEAU GEODESIQUE FRANCAIS 1993",SPHEROID["IAG GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],TOWGS84[0.0000,0.0000,0.0000,0,0,0,0],AUTHORITY["IGNF","REG024"]],PRIMEM["Greenwich",0.000000000,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AXIS["Longitude",EAST],AXIS["Latitude",NORTH],AUTHORITY["IGNF","RGF93G"]]

comment:4 Changed 8 years ago by armin

I just have overlooked the other definitions for RGF93, otherwise I would not have added it a 3rd time...

I found now also a few other entries that seem to exist already, but are missing parameters like datum shift, like OSGB36 or TM65. So I think it would make more sense to modify the current file from trunk and add a DIFF file to this ticket. And I found a few more EU projections which I was missing in the current file, I will add them as well.

I am not sure about the naming conventions and what's best, I tried to base them on the ones from GDAL and EPSG and just putting them in a short form. Sometimes not really easy to give them names that somehow make sense, and I didn't know what is the maximum length.

Changed 8 years ago by armin

Attachment: ecw_cs.wkt.patch added

comment:5 Changed 8 years ago by armin

I uploaded a patch for the modified and newly added EU projection and datum definitions. Compared to my first file I removed also the datum parameters from the pure projection definition since this seems to be the standard way how it is done.

comment:6 Changed 4 years ago by Jukka Rahkonen

This patch has not been applied yet into /trunk/gdal/data/ecw_cs.wkt

comment:7 Changed 4 years ago by Jukka Rahkonen

Summary: Additional CRS definitions for ECW file ecw_cs.wkt[PATCH] Additional CRS definitions for ECW file ecw_cs.wkt

comment:8 Changed 3 months ago by Even Rouault

Milestone: closed_because_of_github_migration
Resolution: wontfix
Status: newclosed

This ticket has been automatically closed because Trac is no longer used for GDAL bug tracking, since the project has migrated to GitHub?. If you believe this ticket is still valid, you may file it to https://github.com/OSGeo/gdal/issues if it is not already reported there.

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