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20001113: higher res topo file (cont.)

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  • Subject: 20001113: higher res topo file (cont.)
  • Date: Mon, 13 Nov 2000 14:59:33 -0700
>From: Robert Mullenax <address@hidden>
>Organization:  Universal Weather and Aviation
>Keywords:  200011101719.eAAHJaD06220 McIDAS-X topography imagery

Robert,

>I was able to make the area file but when I display it using IMGDISP
>using EU=TOPO I only see some color around the coasts.

The TOPO enhancement was designed for images that had elevation values
that range from about -12420 m to +8910 m.  The range of values was
chosen to break the display brightness range right at 148 (a value of
148 is "water" and 150 is "land" (using 128 image colors so that the
values are grouped by twos)).

>Anything inland
>is just a mass of alternating black and white colors.

This sounds strange to me.  When I display the image, it looks correct
especially if I use the image enhancement (or use EB to roll the enhancement
table).

>What enhancement should I use?..

I would start with the TOPO enhancement and modify it to maximize the
contrast while keeping the breakpoint between water and land "correct"
(correct means that Florida does not disappear or become huge).

>or where did I go astray?

I don't think you went astray anywhere (if you used the MAKEAREA positionals
I sent you earlier).  Does the image look weird if you use the IMAGE
enhancement?

Tom