[Xastir] transparency?

[Rick Green]

Thanks to Curt for his patience in working with me on the 'sticky USRadar'
issue.  I still don't understand why I needed automaps on to get anything
to display a few months ago, and now its not needed and causing problems,
but at least I can get maps to display or not without having to stop
xastir and delete files...

  So I'm on to the next level in this learning curve.  Map layers and
transparency.  WHat I'm seeing is that I can overlay Michigan.pdb on top
of (Higher layer number) any raster image, but I can't seem to get any
raster map to overlay another raster map.  The background color, usually
white, seems to totally obscure the underlying raster.  I see in the .geo
files that there is a parameter called 'TRANSPARENCY' which is set to
white in the distributed file, but I still get the white background
obscuring the underlying raster.  Mebbe it's not quite white?  How can I
determine what specific value is in those pixels?
  Also, Terraserver seems to have a problem, in that if even one pixel of
the current view is not available, terraserver gives me no image at all.
Unfortunately, there appears to be a skinny N-S stripe just east of my
home that's missing in their database.  I don't think that's an xastir
problem, but it sure would be nice if they would deliver an image with the
missing pixels transparent, so a toposerver image could show thru.

  I'd like to be able to have the USRadar image overlay terraserver, which
overlays toposerver, with the simple Michigan.pdb vector map on top of all
that.  But without transparent backgrounds, all I see is one raster source
with one vector map on top.
  The GEO file for tigermap is much simpler, and it has its own
configuration dialog.  Is there a way to give it a transparent background,
too?

-- 
Rick Green

"They that can give up essential liberty to obtain a little
 temporary safety, deserve neither liberty nor safety."
                                  -Benjamin Franklin