[gdal-dev] gdal datum shift

[Brian Wilson]

Thanks Frank

I had guessed that I might have to use -s_srs but doing I saw no tangible
results hence my request for more verbose output. "--debug on" was very
useful as was PROJ_DEBUG.

As you surmised, the datum "NAD83_High_Accuracy_Regional_Network" is not
recognized as +datum=NAD83

Then I found that I had missed the step in building Proj.4 of downloading
separately the datum shift zip file. Upon fixing that I am now able to
reproject correctly! HURRAH!

Brian

It can be helpful to run gdalwarp with the commandline
> option "--debug on" in which case the debug output should
> include the PROJ.4 rendering of the source and destination
> coordinate system.
>
> At a very low level you can also define the PROJ_DEBUG environment
> variable to the value ON and PROJ.4 will report some details on what
> datum files are opened.
>
> I think you are going to have to provide a source coordinate
> system with the -s_srs commandline switch to gdalwarp that
> defines a more conventional NAD83 based coordinate system.  You
> might also want to file a ticket on this issue.  Ideally we
> would be smarter about treating NAD83 HARN as equivelent to NAD83
> for most purposes.
>
> Best regards,
> --
>
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam,
> warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent
>
>
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