[Xastir] Why won't this DRG display?

[Bennett, Bruce]

There's a gapping hole in my DRG coverage where this particular GeoTIFF
fails to display - I could use some help understanding why...

The gdalinfo dump looks to me to be very much like other DRG's around it -  

Driver: GTiff/GeoTIFF
Size is 4910, 6693
Coordinate System is:
PROJCS["NAD27 / UTM zone 17N",
    GEOGCS["NAD27",
        DATUM["North_American_Datum_1927",
            SPHEROID["Clarke 1866",6378206.4,294.9786982138982,
                AUTHORITY["EPSG","7008"]],
            AUTHORITY["EPSG","6267"]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","4267"]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",-81],
    PARAMETER["scale_factor",0.9996],
    PARAMETER["false_easting",500000],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]],
    AUTHORITY["EPSG","26717"]]
Origin = (499241.725849,4594820.509966)
Pixel Size = (2.43840000,-2.43840000)
Metadata:
  AREA_OR_POINT=Area
  TIFFTAG_IMAGEDESCRIPTION=USGS GeoTIFF DRG 1:24000 Quad of West Farmington.
Product:359260
  TIFFTAG_SOFTWARE=USGS CD Archiver program tif2usgsdrg v.1.0
  TIFFTAG_DATETIME=1996:10:09 13:47:29
  TIFFTAG_XRESOLUTION=250
  TIFFTAG_YRESOLUTION=250
  TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
Image Structure Metadata:
  COMPRESSION=PACKBITS
Corner Coordinates:
Upper Left  (  499241.726, 4594820.510) ( 81d 0'32.71"W, 41d30'24.94"N)
Lower Left  (  499241.726, 4578500.299) ( 81d 0'32.64"W, 41d21'35.71"N)
Upper Right (  511214.270, 4594820.510) ( 80d51'56.26"W, 41d30'24.66"N)
Lower Right (  511214.270, 4578500.299) ( 80d51'57.35"W, 41d21'35.43"N)
Center      (  505227.998, 4586660.404) ( 80d56'14.74"W, 41d26'0.26"N)
Band 1 Block=4910x1 Type=Byte, ColorInterp=Palette
  Color Table (RGB with 256 entries)
    0: 0,0,0,255
    1: 255,255,255,255
 <---------------snip-------------->
  254: 254,1,2,255
  255: 255,255,255,255
----------------------------------------------------------------------------
-----------------------------------------------------------
I note that the "TIFFTAG_XRESOLUTION=250" (and Y) is a larger value than
surrounding DRG's ("TIFFTAG_RESOLUTION=72") but I don't know what bearing
that might have, if any.

Any clues?  Any helpful debugging procedures?

THANKS!

Bruce Bennett
BBennett at Spang.COM
(440) 352-8600 X 3350
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