Re: IDL plot is inconsistent, where is subtle error?

[bleau(at)umtof.umd.edu (Lawrence Bleau)]

Thank you, Craig Markwardt <craigmnet@cow.physics.wisc.edu> and Paul van Delst
<paul.vandelst@noaa.gov>, for your suggestion to subtract off a base epoch.  A
coworker of mine gave me the same suggestion last night, which I tested. 
You'll be happy to learn that it worked!

Also, your insights about direct graphics being single precision in IDL V5.2,
but double in V5.4, were quite enlightening and would explain the missing tick
mark.  I'll definitely upgrade and retest this later on (anything to simplify
this code).

Btw, the missing tick mark was not just on the even hour; that was a false
pattern.  I ran it with a whole range of ending hours, and only 2 in 10 worked
as expected.  I was using XTICKV already, btw, and passed it a DOUBLE.  That's
moot, though; since I put in the base epoch subtraction it works like a charm. 
If you're curious as to how this plot developed, look at

http://umtof.umd.edu/sem/latest4hrs.gif

For info on the science project from which this data was obtained, see

http://umtof.umd.edu/sem/

Thanks again!

Lawrence Bleau
University of Maryland
Physics Dept., Space Physics Group
301-405-6223
bleau@umtof.umd.edu