[gdal-dev] reading Arc/Info Binary Grid

[Robert Denham]

Frank,
it appears there are two ways to specifiy the projection information
for UTM here. The one you might be more familiar with looks like this:

f2 [site1biggrd2m]> cat prj.adf
Projection UTM 
Zone 56 
Zunits NO 
Units METERS 
Spheroid AUSTRALIANNATIONAL 
Xshift 0.0000000000 
Yshift -10000000.0000000000 
Parameters 

This contain no parameters, and zone information etc is referenced
directly. The other:

> > f2 [64676964grd1l]> cat prj.adf
> > PROJECTION UTM
> > UNITS meters
> > SPHEROID WGS84
> > DATUM WGS84
> > PARAMETERS
> > 153 0 0
> > -40 0 0
is actually the result of exporting an imagine .img file to a grid. It
seems that enough information is there to set the zone and offset ok (for
example the central meridian of zone 56 is 153, and presumably -40 is
equivalent to a y offset of -10000000. 

I think I will try to use native arc/info grids, rather than the converted
ones from imagine, but this might be something to think about in future.

thanks for you help.

Robert