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From: Matt H. <mkh...@ta...> - 2002-01-09 16:05:13
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All, On the chance that someone else will make the same dumb mistake I did I thought I'd post this follow-up. I was having trouble with maketopo on an SGI platform. After launch, vis5d issued numerous "nan" messages and the topography displayed as a flat sheet. I thought this was a bug in the SGI implementation as a similar complaint was posted by another SGI user. It has nothing to do with the SGI. Here is the answer. Pay close attention to the units! The vertical scale in my 3-D volume was in kilometers. The vertical units in my topography data was meters. Use v5info to check your units and ranges. Use v5dedit to correct them if needed and use topoinfo to check your topography. Here is another tip. Your topography field can be very much larger than the horizontal domain of your volume. For many applications EARTH.TOPO will do since it covers the globe (but it doesn't have subsurface topography, ie. seafloor). I made a single topography file for the entire Gulf of Mexico. Now any subregion of the Gulf of Mexico I want to visualize will have the properly registered subregion of the bathymetry. In other words the topography doesn't have to match perfectly with the horizontal region of your volume. I know many of you already knew all this. Now it's here for posterity. Thanks to James T. Potemra for setting me on the path to the solution and to Jim Edwards for suggesting other avenues to examine. Matt +----------------------------------------------------------------------+ | Dr. Matthew K. Howard Voice: (979)-862-4169 | | Department of Oceanography FAX: (979)-847-8879 | | Texas A&M University Internet: mkh...@ta... | | College Station, TX 77843-3146 webcam: http://seawater.tamu.edu | +----------------------------------------------------------------------+ |