[Xastir] vertical lines in hi-res geotiff orthophotography

[Kevin Ratcliff]

Hi all,

I'm trying to use some high-resolution (.15 meter) aerial photos in
Xastir. The files in question work great, except at zoom levels 1 and
2. At those zoom levels I see lots of gray vertical lines that obscure
the image to the point where it's no longer useful. I don't see this
issue using DRG topo files.

Here is a link to the source files for free downloads and metadata:

http://www.indiana.edu/~gisdata/local/atterbury_muscatatuck2010.html

There is a SAR training center inside Camp Atterbury Joint Maneuver
Training Center that various area SAR teams use frequently, and it
would be nice to be able to take full advantage of this imagery.

Before I could use the files in Xastir, I had to run GDAL's rgb2pct.py
script on them. That's the only modification I made. After doing that
and seeing the problem in Xastir, I opened one of the files in qgis
and it looks just fine at high zoom levels.

I tested on multiple systems (two Ubuntu 10.04 and one Ubuntu 10.10,
all installed using the Ubuntu wiki instructions for CVS and the
UbuntuGIS PPA). One of the systems is at CVS from January 17, 2011,
the others are a few weeks older. Two are desktops and one is a
laptop, so the video hardware differs quite a bit; none are VMs. I'm
about to try a fresh Fedora install to see if it does the same thing.

What information do you need from me to help track this down?

What debug level should I set in Xastir? Currently I'm not seeing any
errors or warnings in the terminal.

Thanks!

Kevin
KB9MQU

PS - I am not a GIS person, and my linux knowledge is still not where
I'd like it to be, so it's very likely this is user-error on my part.
I just don't know where I went wrong!