BSB/PAK files

[Frank Warmerdam]

Gregor Mosheh wrote:
> Hi, all.
> I have a set of nautical maps in BSB format (.PAK files). I am very 
> familiar with doing tileindexes and the like on TIFFs, but when I try to 
> use these PAKs, I get nothing but white space. I've double-checked that 
> the coordinates and SRS are correct...
> 
> Are there any caveats to using BSB/PAKs? I can't find anything on Google 
> about folks using them in Mapserver, only mention that GDAL supports them.

Gregor,

Could you perhaps provide the gdalinfo report on one of the files?  The
main problem with using BSB files in MapServer is that GDAL treats them as
lat/long with a set of four (or so) ground control points.  This georeferencing
model is not supported by MapServer.

One option is to gdalwarp them into more normal "origin and pixel size" form.
Another approach would be to improve the driver to actually understand the
underlying projection (Mercator most of the time I think) and represent the
files georeferencing properly in that coordinate system.

Also, be warned that many modern BSB files are not supported by GDAL as some of
the data vendors have added new encryption schemes to prevent data purchasers
from having meaningful access to their data.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | President OSGeo, http://osgeo.org