[gdal-dev] MapInfo Datum lookup bug, CSV data for drivers

[Frank Warmerdam]

Qi-Shan Lim wrote:
> Hi all,
> 
> I'm new to GDAL/OGR development and have run up against an existing
> bug with the MapInfo driver, which I'm willing to help fix. Details
> are at http://trac.osgeo.org/gdal/ticket/481#comment:8 with a comment
> which I'll reproduce here for convenience:
> 
> I'm hitting this problem as well and really need to get it resolved.
> Only just started working with gdal/ogr so comments would be
> appreciated on this proposal:
> 
> ---
> 1. Change asDatumInfoList to include the EPSG code for the datum. I
> imagine this could be accomplished with a mixture of pattern-matching
> the names and some manual intervention.

Qi-Shan,

I agree that this would be a good idea.  The MITAB code predates some
of the EPSG support in OGR (particularly the use of authority[] nodes,
and so it was not included originally.  Populating the column may not
always be practical though.

> 2. Change SetSpatialRef? to look up the data based on the datum's EPSG
> code instead of name i.e. use poSpatialRef->GetAuthorityCode?("DATUM")
> instead of poSpatialRef->GetAttrValue?("DATUM")

Seems reasonable where available.

> 3. (Optional) Move asDatumInfoList (and the other hard-coded data, I
> guess) into a csv file.

I'm not too keen on moving it into a CSV file as currently MITAB
in standalone mode has no dependency on external files which keeps it's
use quite a bit simplier than would otherwise be the case.

> Is this going to work or am I talking rubbish? If it sounds reasonable
> I'll go ahead and do up a patch.

Thanks.

Best regards,
-- 
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