[Fwd: [UMN_MAPSERVER-USERS] different symbol for elements of the same layer via cgi?]

Stephen Woodbridge woodbri at SWOODBRIDGE.COM
Thu May 31 16:55:46 EDT 2007

Schuyler Erle wrote:
> * On 31-May-2007 at 10:25AM PDT, Stephen Woodbridge said:
>> Steve L,
>> Here is a good use case for being able to bind a column to a symbol 
>> image. I'm not sure if you had thought of this or if this would be 
>> possible. But how about something like:
>> SYMBOLIMAGE "/path/to/symbols/[symbol].png"
>> SYMBOLIMAGE [symbol]
> I have a concrete use case for this, if I understand the problem
> correctly. I have a table of POIs and I want to display different
> icons based on the POI attribute. Unless I'm sorely mistaken, I
> haven't been able to figure how to do it with MS 4.10 without
> resorting to MapScript.

Right! Steve has been doing some work make it easier to bind stuff to 
attribute columns as in both of these examples. If you have a fixed 
number of symbols then you can use CLASS EXPRESSIONs to select the 
symbol, but in the example above EVERY point had a unique symbol image. 
I think this case needs to be handled a little differently than the 
SYMBOL case. With SYMBOLs there is some preprocessing to cache the 
symbols. In the all or most are unique class, you probably just want the 
  path or URL to the symbol and have it copied into the image.


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