[Xastir] Re: USGS DRG files no longer free.. (Tyler Allison)

[Tom Russo]

On Mon, Oct 06, 2003 at 12:00:05PM -0400, a Mr. Richard Feyler of Fort Lee, New Jersey <tyler at allisonhouse.com> writes 'Dear Rosanne Rosannadanna':
> 
> I've gotten closer though on the actual file..
> 
> 'listgeo b40.tif' shows:
> 
> Corner Coordinates:
> Upper Left (1497206.413, 593091.362)
> Lower Left (1497206.413, 545590.098)
> Upper Right (1535233.786, 593091.362)
> Lower Right (1516220.099, 545590.098)
> Center      (1516220.099, 569340.730)

These look like the UTM coordinates of the corners.  Just use "cs2cs" 
(installed when you installed proj4) to convert back to lat/lon.  You will
need your UTM zone and the map datum (NAD27 or NAD83) to do that.  For
example, if you were me here in UTM zone 13, using a NAD83 map:

  cs2cs -r +proj=utm +zone=13 +datum=NAD83 +to +proj=latlong 
  1497206.413 593091.362    (input)
  104d8'22.835"W  13d32'30.159"N 0.000 (output)
[...]

You need the "-r" there so you can input northing/easting (the order they
appear in your listgeo output) instead of easting/northing (the normal
order, "read right up").

'Course you're not in UTM zone 13, so you'd have to figure that out first.
Once you have the four corner lat/lons, you can create an FGD file really 
easily.

-- 
Tom Russo   KM5VY    QRPL #1592   K2#398    http://www.swcp.com/~russo/
Tijeras, NM DM64ux   SOC #236     AHTB#1    http://www.qsl.net/~km5vy/
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