[gdal-dev] Non-EPSG projections, esri_extra.wkt and best practices

[Tyler Mitchell]

Jorge, are you able to just provide the full PROJ syntax instead?
+proj=robin +lon_0=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs 
Aside from that, you can just copy/append the ESRI definitions to the end of the EPSG main file and GDAL should pick it up.

Tyler

On 2013-06-03, at 8:00 AM, Jorge Arévalo wrote:

> Hello, 
> 
> Let say I want to warp this raster file https://dl.dropboxusercontent.com/u/6599273/gis_data/utm.tif
> 
> From its original projection, EPSG:26711, to Robinson projection, not part of EPSG. So, I need to provide the correct frame of reference, and GDAL will be able to do it. 
> 
> I could download the OGC WKT definition from http://spatialreference.org/ref/esri/54030/ogcwkt/, and pass the downloaded file to gdalwarp, like:
> 
> gdalwarp -s_srs epsg:26711 -t_srs robinson_file.wkt utm.tif utm_warped.tif
> 
> The thing is I'm working with an app that uses GDAL to warp raster files. The information this app handles (and it's hard to change) related with non EPSG projections is something like ESRI:54030. I know this is something that GDAL doesn't accept. But I see, in GDAL_DATA directory, a file named esri_extra.wkt. This file contains a line like this:
> 
> 54030,PROJCS["World_Robinson",GEOGCS["GCS_WGS_1984",DATUM["WGS_1984",SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Robinson"],PARAMETER["False_Easting",0],PARAMETER["False_Northing",0],PARAMETER["Central_Meridian",0],UNIT["Meter",1],AUTHORITY["EPSG","54030"]]
> 
> This is the number of the ESRI projection followed by the WKT definition. So, my question is: Is there any "right" mechanism, maybe provided by GDAL, to make the warping operation? Something that gets ESRI:54030 as input, looks in this file (or where needed) and gets the wkt definition as output, that can be safely used with gdalwarp.
> 
> Many thanks in advance, 
> 
> -- 
> Jorge Arevalo
> Freelance developer
> 
> http://www.krop.com/jorgearevalo
> http://about.me/jorgeas80
> 
> Enviado con Sparrow (http://www.sparrowmailapp.com/?sig)
> 
> 
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Tyler Mitchell
Engineering Director 
Actian Corporation
tyler.mitchell at actian.com

MOBILE 250-303-1831
SKYPE spatialguru
www.actian.com

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