[mapserver-users] COLOR can take an expression?
Paul Ramsey
pramsey at cleverelephant.ca
Fri May 16 10:47:49 PDT 2008
Short answer "no". Your approach is intriguing though :)
You'll find that people can only distinguish between about 5 colors
reliably anyways, so for practical purposes, a five-class color ramp
will do, and is not *that* onerous to build.
P.
On Fri, May 16, 2008 at 6:15 AM, Tom Huras <tjh at extensys.com> wrote:
> I'm learning MapServer so my expectations for what it does may be incorrect.
>
> I want to assign a color to some features from a database based on a
> field. The full range of values is large, so I don't want to code a CLASS
> for each value. Instead I'd like to use an expression for the color.
>
> For example, if the attribute of a feature ranges from 0 to 1000, I'd like
> to use it to drive a range of the color green:
>
> LAYER
> DATA "the_geom from myFeature"
> CLASSITEM "col1"
> TYPE LINE
> ...
> CLASS
> NAME "myFeature"
> STYLE
> COLOR 0 ([col1] / 1000 * 255) 0
> WIDTH 1
> END
> END
> END
>
> Thanks
>
> /tom
>
> --
> Tom Huras, P.Eng.
> Partner
>
> ExtenSys Inc.
> 31 Plymbridge Cresc (416) 481-1546, Mobile (416) 859-1313
> North York, Ontario M2P 1P4 Fax (416) 481-6714, Home Fax (416) 516-7438
> www.extensys.com tjh at extensys.com
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