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20031126: Using Short Integer values in IDV, and absolutes Co lor Tables

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  • Subject: 20031126: Using Short Integer values in IDV, and absolutes Co lor Tables
  • Date: Thu, 27 Nov 2003 10:03:30 -0700
>From: Bernard Mendiburu <address@hidden>
>Organization: UCLA
>Keywords: 200311262230.hAQMUREH012178 IDV color ranges

Hi Bernard-

>Here's the question of the day ;-)
>We're using short integer values (0 to 255)
>In the "properties" widget the Zero used to be converted in a strange
>near-zero float like 8.8E-7 or 6.7E-7
>Strange insn't it ? I would have expected a simple Zero.

Probably a rounding error.

><joke>
>Is it because the absolute zero doesn't exist in Temp ?
></joke>

>Sometimes, we want to display two variables in the same "colorspace"
>But one's max is, say 255, and the other's max is, say 127.
>The color table for is streched all over the respectives ranges.
>Then one's 127s will be shown in "midle" color, and the other's 127s will be
>in "max" color.

You can change the range of the color table used for any variable
by right clicking on the color bar in the legend and using the 
Change Range... option.

>Is there a way to set an "absolute" color table, rather than "relative" to
>min/max

If your variables always have the same name, you could create a
default for that parameter using the Parameter Defaults editor.
From the Edit->Resources->Parameter Defaults menu (each -> refers
to a submenu), you can set the default color table, range, contour
interval and unit for a particualr parameter.  In this dialog,
you will see two tabs.  The first tab is the user defined defaults
and the second is the system defaults.  Click on the system tab
to see how these are defined.  parameters are either absolute
names or regular expresions.

In the user tab, you can enter the name for the parameter in the
first column. Right clicking on the row will bring up a list
of options for setting the range and color table.  You might
want to check out the relevant section from our recent
User's Workshop at:

http://my.unidata.ucar.edu/content/software/IDV/docs/workshop/resources/parameters/index.html

Eventually, we will turn this workshop into a tutorial but for now it
might be useful.

>Thanks
>& Happy Thanksgiving

Thanks and same to you.

Don Murray
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