[gdal-dev] Re: bil file headers

[Frank Warmerdam]

Derrick,

I have completed a simple DOQ reader for GDAL. It supports the "old" USGS DOQ 
header format. I can add the new tagged format too, if you find yourself
using it. 

The reader only works for UTM (not geographic, or state plane) but should
support the four common datums. It also attempts to properly capture feet
vs. meter units from the file. UTM projections are currently turned into
the detailed Transverse Mercator definition. Let me know if this is a problem
and I will extend the GeoTIFF writer (and OGRSpatialReference class) to support
automatic recognition of UTM projections. 

I have only tested with the derry_pa_sw.bil file you mentioned. I downloaded
one of the other DOQs but it was already in GeoTIFF. It should work for RGB
files, but has only been tested with BW. It won't work with files that include
elevation or an RGB and BW image. Once again I am willing to extend it given
examples of other variations. 

Best regards,

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and watch the world go round - Rush | Geospatial Programmer for Rent