[Vis5d-users] Re: maketopo no make topo -II (final)

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 |
+----------------------------------------------------------------------+