[Qgis-developer] color ramps for vector graduated symbols (ticket #782)

Marco Hugentobler marco.hugentobler at karto.baug.ethz.ch
Thu Oct 25 09:00:00 EDT 2007

Hi Perrygeo,

A flexible solution for color ramps as you describe it in ticket 782 would be 
a really great enhancement for qgis. 

>The remaining questions are: 
> - what file format works to define the color ramps? have to allow for all 4 
>of the above types. As much as possible, leverage existing formats like gmt 
>and grass color ramps. 
 >- how do the ramps get "registered" with qgis so that they can be made 
>available to the user? 
>- how do they get integrated with the UI? preferably a dropdown list of color 
>ramps with a small representative image of the ramp itself. 
> - how to we implement the algorithm to determine the rgb color for ramps of 
>type #1 and #2?

Registered ramps could be stored in a dedicated directory under share/qgis, 
similar to the way it is done with the svg markers.

Hopefully you can find a good storage format for the ramps. If there is no 
format that meets all your requirements, you could still design your own xml 
based language  (crml = color ramp markup language)


Dr. Marco Hugentobler
Institute of Cartography
ETH Zurich
Technical Advisor QGIS Project Steering Committee
marco.hugentobler at karto.baug.ethz.ch

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