[Qgis-user] 1928-1930 USGS maps

[Jan Becket]

After much effort, I obtained an old set of 1928-1930 USGS topo maps of Oʻahu Island, Hawaiʻi - for a project I am working on. The maps are without collars and used by a local archaeological firm. The geotiff maps at first showed as completely black on my Mac system (10.10.5 - Yosemite). However I found this link with a resultuion for the issue:

http://stackoverflow.com/questions/13925995/options-to-convert-16-bit-image <http://stackoverflow.com/questions/13925995/options-to-convert-16-bit-image>

I opened the 16 quads for Oʻahu in Photoshop and applied auto levels, after which they became discernable quad maps. However, when imported into QGIS, they are now invisible. I wonder if it is possible that I stripped away the geotiff CRS information. Prior to the Photoshop operation, the maps did appear correctly referenced to Oʻahu Island (although they were totally opaque / black).

Now, the maps in QGIS are not visible, although the geotiffs are several megabytes in size and are visible when opened in Photoshop, Preview, or whatever image viewer. 

I should mention that I have successfully imported other sets of USGS maps of Oʻahu for this project - the 1902 series, the 1916 series, the 1935 series - as well as the current series. The early maps used the Old Hawaiian CRS (EPSG 3564) but more modern maps use WGS83, Zone 4N (EPSG 3711). I have on the fly projection enabled and have tried many CRS settings for the maps, but nothing results in a visible quad appearing.

Suggestions very welcome ...
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