[Mapserver-users] Using MapServer as a general graphing engine

[Daniel Morissette]

Armin Burger wrote:
> 
> I also found it sometimes desirable to have Mapserver create thematical
> maps with pie charts or bar charts, etc. I don't know how much work it
> might be to implement this. Maybe DM Solutions OWTChart could be somehow
> included?
> 

Creating an (optional) extension for MapServer using GDChart (the engine 
behind OWTChart) would be technically possible.

However most of the work would be to define what we want to do with 
charts and how they interact with the map, which mapfile parameters are 
required to control them, etc.  If you guys could come up with some kind 
of requirements/specifications with examples of what you want to see 
then that could help selling the idea for a future release.


> Another, probably a bit easier implementation, could be using MapScript
> combined with graphic modules/extensions for Perl or PHP, mainly based on
> the GD library. But as far as I know there is no possibility to include
> externally produced images and merge them on top of the map image. A
> question to the developers: would it be possible to have a Mapscript
> method that creates an imageObj from a file?
> 

You could do the reverse: save your map image and load it using the PHP 
GD extension and use the PHP GD extension to paste the charts on top of 
the map.

As you wrote already, this would work fine only for a small number of 
charts. As the number of charts to draw on the map increases, the 
overhead of external calls to create charts and save them to temporary 
images could become significant.

Daniel
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  Daniel Morissette               morissette at dmsolutions.ca
  DM Solutions Group              http://www.dmsolutions.ca/
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