[maplab-users] How do you display a layer by attribute?

Zak James zak-ms at hoppsan.org
Fri Jun 25 13:55:27 EDT 2004


You need to specify a separate class for each value or value range of 
the attribute that you want to differentiate. Multiple Style objects 
are used within each class to build layered symbolization (for instance 
a star within a circle for point markers or a fill with a contrasting 
outline for polygons). One serious bug that I can warn you about: don't 
give a Style a name in Mapedit or it will break your mapfile. This 
problem will be addressed in the upcoming release.


Zak James
Applications and Software Development
DM Solutions Group Inc.

On Jun 25, 2004, at 1:05 PM, Ken Sanderson wrote:

> Hello all.
> How do you set up a map file through map edit to display a layer by an
> attribute value. So for example if I have a field called TYPE and in
> that field you can have a value of 1-4. I then want to display all 1's
> as red, 2's as blue, 3's as green, 4's as yellow on the map.
> How do I go about setting that up? I assumed that I would set ClassItem
> to TYPE, but not sure how to go about defining a style object for each
> value type could be?
> Thanks,
> Ken
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