Gib,
This is probably due to the fact that your Image has much more
resolution than the grid you're mapping it onto. In order to improve
this, use the Refine module on your grid and see if that helps.
David
You will not be surprised to learn that my problems with Map resulted from
an oversight. Because I wasn't careful with my coordinates, I was actually
mapping elevations from an area outside my data region (which doesn't fill
the rectangle), therefore the 0 values were correct. Sorry to waste
bandwidth.
But wait, there's more! I am now rendering my image with the TIFF painted
on the rubbersheeted surface. To recap, I first create a grid with the same
connectivity as the TIFF, but with positions in the frame of reference of
the elevation data. I then Replace the colors in this field with the TIFF
colors. At this stage I have a nice looking image. Meanwhile I have
Imported the elevation data (which when Rubbersheeted produces a nice
surface). I then use Map to put elevations into the object with the TIFF
colors. If I render at this point it still looks fine. The final step is
to Rubbersheet the field. The image produced does not look nice. The
elevations are correct, and the colors are roughly right, but there is an
ugly graininess. Zooming in shows that something bad has happened, an odd
effect that is hard to describe but looks a lot like a bug.
I have found that the image is cleaned up if I Collect it with an
AmbientLight. Since AmbientLight removes the default lighting, which is
ambient [0.2 0.2 0.2] plus a distant light, I'm guessing that the problem is
related to what happens to the image lighting/colors when Rubbersheet is
applied. Anyway, I now have something useable, and have learned a lot
through all this. Thanks to all who offered help.
Gib
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.............................................................................
David L. Thompson Visualization and Imagery Solutions, Inc.
mailto:[EMAIL PROTECTED] 5515 Skyway Drive, Missoula, MT 59804
Phone : (406)257-8530
