Gib Bogle: |...the main problem. My coordinates are of the order of (2000000,6000000), |delta in the elevation data is 1.0, and in this frame the TIFF delta is |0.24. If the coordinates are all translated by (-2000000, -6000000, 0) the |image after Map (to put elevations into the TIFF-like field) and RubberSheet |is much improved. ... |David suggests that someone else in the group may be able to suggest why |this is happening. I can see that numbers like these could create a problem |if DX was using single precision. Is this the case?
Yes. Sounds like you're dealing in 9 decimal digits of precision, and single precision only gives you in practice about 4. To answer your next question, DX doesn't support double positions. I hit this under cimcumstances similar to yours. The recommendation from the list was the offset-the-data method you've found as adding support for double positions is (unfortunately) non-trivial. |Although the image is greatly improved when the origin is shifted in this |way, it is still not as good as it could be. The final step of Collecting |the output of RubberSheet with an AmbientLight cleans it up. Can anyone |suggest why removing the default lighting should solve this problem? By doing this I believe you're removing the specular and diffuse from your lighting and possibly changing the ambient intensity. Try adding in a Shade module and zero out the specular/shininess (without other information, specular on terrain looks really fake). Then, make that your colors are position-dependent, and experiment by turning on smooth shading (Shade module). Randall -- Randall Hopper (mailto:[EMAIL PROTECTED]) Lockheed Martin Operation Support EPA Scientific Visualization Center US EPA MD/24 ERC-1A; RTP, NC 27711
