[Xastir] data in .fgd file for geotiff map

[Wendell Turner]

I'm using FAA sectionals from
  http://aviationtoolbox.org/raw_data/FAA_sectionals/current/
which are (rather large) GeoTiff files.  I have them as maps to
xastir, and the longitude seems to be right on, but the latitude
seems to be about 1.4 minutes off.

The site these are from has a .tfw file (for each .tif file)
that contains
  63.753925000000002
  0.0
  0.0
  -63.753925000000002
  -378078.33973611565
  -18298.274814258024
(there are no .fgd files at the site).  Can this be converted to
the .fgd file?

It looks nothing like what mapfgd.pl produced for the map, which
is
  1.5.1.1   WEST BOUNDING COORDINATE:  0.000000
  1.5.1.2   EAST BOUNDING COORDINATE:  0.125000
  1.5.1.3   NORTH BOUNDING COORDINATE:  0.000000
  1.5.1.4   SOUTH BOUNDING COORDINATE:  -0.125000
so I suppose it is something in this file that is incorrect.

Or, is there some number I can copy out of the listgeo output to
put into the .fgd file?

Also, the chart legend and borders appear in the xastir window,
I suppose I'll need to get rid of those also.

Wendell