dynamic symbols, eg bar graphs or pie charts

Daniel Morissette dmorissette at MAPGEARS.COM
Fri Jun 9 17:25:44 EDT 2006

thomas bonfort wrote:
> Steve and Daniel: the url type symbol does seem promising feature-wise. 
> but once again the overhead of network request and probably two 
> intermediate files (one for owt, one for MS) seems quite important.

True, there can be a performance hit for large numbers of symbols, but
using an external service via a URL to produce the chart or dynamic
symbol gives maximum flexibility to the users to return whatever they
like and not just charts.

Anyway, if you insist on direct integration inside MapServer, then I'd
recommend that you look at gdchart which is used by OWTChart
(http://maptools.org/owtchart/)... the original version of gdchart was
messy with a bunch of global variables and static stuff that didn't
build well on all platforms, and for owtchart I reworked it to replace
the global vars with a struct and make it more multi-platform. You'll
find that version in directory "gdchart2" in the owtchart source
package. The only other dependency of gdchart is GD (and its own
dependencies), that would be fairly easy to integrate.

Daniel Morissette

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