[Gdal-dev] issue warning to user when performing datum shift (OGR, GDAL)

Frank Warmerdam warmerdam at pobox.com
Mon Jul 31 16:58:53 EDT 2006


Dylan Beaudette wrote:
> Hi everyone,
> 
> 
> In light of some recent thought, experimentation, and discussion [1] I
> am wondering if it would be at all possible or even desirable to warn
> the user when a datum shift operation is about to be performed. Within
> the US, and assumming that the NADCON grid was installed with Proj4,
> transforming between NAD27 and NAD83 should work just as expected.
> However, in other parts of the world, this may not be the case.
> Therefore, it might be a good idea to follow the model used in GRASS,
> where the user is specifically prompted for datum transform parameters
> whenever defining a new locatio, in these situations.
> 
> Any thoughts / reasons not to do this?

Dylan,

Well, the most obvious reason not to do it is that the GDAL utilities
are not interactive.  So there is no opportunity to ask.

I think it would be very nice if there was a mechanism to ask stuff
like ogr2ogr to describe what it will do in a transformation but even doing
that would be pretty challenging.

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    | President OSGF, http://osgeo.org




More information about the Gdal-dev mailing list