[Gdal-dev] GML and GDAL

[Frank Warmerdam]

On Wed, 26 Jan 2005 09:39:12 -0500, Clay, Bruce <bclay at ball.com> wrote:
> 
> Sorry if these questions are off track but it seems that the GDAL user group
> if probably the most competent group to ask these questions. 
>  
> Can anyone describe in laymen's terms how the Geography Markup Language
> (GML) would be used between a 3D terrain visualization tool and external
> users? 

Bruce, 

I can imagine a few ways, but your question seems a bit peculiar.  GML
would be a reasonable format to provide view position, DEM and feature
overlay data to a 3D terrain visualization tool but of course the end user
isn't going to be entering GML directly. 

> Does GDAL have any support for GML? 

There is an OGR driver for reading and writing GML data. It has a
variety of limitations but works reasonably well for simple GML datasets.
Note that OGR is a feature interface.  So it is used to read GML files full
of point, line, and polygon features.  Not raster DEMs. 

> Is there any particular reason to use or not use GML to control a GUI less
> visualization tool from an external GUI? 

GML is a geographic data encoding format.  It could be used as an input
format to a visualization service but in general I would not imagine it
being used the way you suggest.   Of course, I am not sure what
sort of decoupling your are trying to establish between the GUI and the
backend. 

Best regards,
-- 
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