[Gdal-dev] gdal_grid: Comments from a new player

[Frank Warmerdam]

Fodder wrote:
> Hi All,
> 
> Just a few things I've noticed since I've been playing around with gdal_grid
> (I'm using the vrt/csv driver):
> 
>    - It's important to put the whole path of the csv file in the vrt file
> (even if they're in the same directory) if you are running gdal_grid.exe
> from a different locaion.

Fodder,

I believer there is a "relativeToVRT" attribute on the filename element
in the VRT file that can be set to 1 (or TRUE) if you want the path to
be interpreted as relative to the vrt file.

>    - With the EHdr output format, it seem to be necessary to switch the YMin
> & YMax around in the -tye parameter. The YMin value seems to be used for the
> ULYMap tag in the .hdr file. Is this a bug?

no idea.

>    - A lat/long WGS projection reference seems to be added to the grid if no
> projection string is passed. I would have thought that a blank projection or
> non-earth projection would be better.

no idea.

> Finally, a question, to integrate this with a windows app, how do I know
> when gdal_grid is finished? Can I test for the existance of the output file
> with certain permissions or could this lead me astray?

Depending on how you launch he subprocess there should be a variety of ways of
testing if the process is complete.  You can't be confident that the file is
completely written till the gdal_grid process terminates.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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