[gdal-dev] FW: Converting Geomedia Terrain ASCII files to geotif

[Frank Warmerdam]

Moskovitz, Bob wrote:
> Hello All,
>  
> I am looking for a way to convert Geomedia Terrain ASCII files to 
> geotif.  Below is an example of what this file looks like.  It is a 
> NAD27 California State Plane Zone 3 file.  People have suggested that I 
> strip the header and use a VRT to do this, but the docs seem to suggest 
> that it does not work with ASCII data.  Any other ideas?
>  
> Thanks in advance,
> Bob
>  
>  
>  
> ASCII Z GRID
> XORIGIN=480438.521976
> YORIGIN=141096.092712
> NUMROWS=532
> NUMCOLUMNS=876
> ROWSPACING=30.48
> COLUMNSPACING=30.48
> SCANORIGIN=TL
> ORDER=row
> VUOM=ft
> VOID=-9999
> VERTICALDATUM=NAVD88
> -9999
> -9999
> -9999
> -9999
> .
> .
> .
> .
> [ NUMROWS x NUMCOLUMNS 'th row]

Bob,

You could replace the header portion with the header lines for an
ESRI ASCII Grid.

eg.

NCOLS 170
NROWS 148
CELLSIZE 40
XLLCENTER 1724520
YLLCENTER 5125840
NODATA_VALUE -9999
  1518.621 1410.902 1290.767 1236.527...

I think the AAIGRID pixel values are one text line per scanline
but I don't think the reader code cares about what kind of white
space appears between pixel values so it should work.  Well, I'm not
absolutely sure of that.

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