[GRASS-dev] [GRASS GIS] #2456: read CSV from GDAL data directory

[Paul Kelly]

Hi Markus, Even,

On 04/24/2016 10:29 PM, Markus Neteler wrote:
> Hi Paul,
>
> you are probably the person with most insights into lib/proj/convert.c.
>
> I try to debug why the North Carolina Location cannot be generated
> properly (EPSG 3358) but comes out like this:
>
>
>   grass71 -c epsg:3358 ~/grassdata/nc_data
>   GRASS 7.1.svn (nc_data):~ > g.proj -w
>   PROJCS["NAD83(HARN) / North Carolina",
>       GEOGCS["grs80",
>           DATUM["unknown",

The datum name "unknown" is coming through from GDAL. Here is a simple 
test program to illustrate it (using latest SVN GDAL from this evening):

#include <stdio.h>
#include <ogr_srs_api.h>

main()
{
     OGRSpatialReferenceH hSRS;
     const char *datum;

     hSRS = OSRNewSpatialReference(NULL);
     OSRImportFromProj4(hSRS, "+init=epsg:3358");

     datum = OSRGetAttrValue(hSRS, "DATUM", 0);
     printf("Datum name is %s\n", datum);

     return 0;
}

Compile as:
gcc -Wall -o test test.c -lgdal
and run:
./test
Datum name is unknown


Perhaps there is a better / more correct way to get the co-ordinate 
system definition from GDAL than by requesting it as a "+init=epsg:XXXX" 
PROJ string?

Paul