[mapserver-users] color attribute question

[Carlos Ruiz]

Do,

If you want to do this without using mapscript, you can pull the gradient calculation as an attribute from your data table.

ALTER TABLE mytable ADD COLUMN gradient_color VARCHAR;
UPTATE mytable SET gradient_color = floor(gradient * 255)::text || ' 0 0';

Cheers

 Mtro. Carlos Ruiz


On Monday, June 23, 2014 4:59 PM, "Lime, Steve D (MNIT)" <Steve.Lime at state.mn.us> wrote:
 


You can compute a color string using PostgreSQL string functions:
 
  SELECT percentage || ‘ 0 0’ AS color FROM …
 
Steve
 
From:mapserver-users-bounces at lists.osgeo.org [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Do Wi
Sent: Sunday, June 22, 2014 3:50 PM
To: mapserver-users at lists.osgeo.org
Subject: [mapserver-users] color attribute question
 
hi!
 
i have this scenario:
i have a column in my postgis table which contains a double representing a percentage.
 
i want to color my polygons in a gradient fashion based on that number.
 
the docs states three ways to specify color:
1. three [1-255] numbers
2. hex string
3. [attribute]
 
but the attribute must be a string by itself in the same format as options 1 or 2.
 
how can i achieve something like 
 
COLOR [percentage]*255 0 0
or
COLOR [percentage] 0 0
if percentageis already 0..255
 
for a red gradient for example? 
 
thanks allot!

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