Hi Peter, Many, many thanks for that.
Anyway, QGIS is throwing many exceptions at my code! Need to understand how things work... Thanks again! Benoit > -----Original Message----- > From: [email protected] > [mailto:[email protected]]on Behalf Of Peter Ersts > Sent: Thursday, 05 August 2010 15:33 > To: [email protected] > Subject: Re: [Qgis-developer] How to load a colour table on a > raster,programmatically (in python)? > > > On 08/05/2010 05:25 AM, Benoit de Cabissole wrote: > > Could you please point me to the function(s) that are used to > match a custom > > colour table (QgsColorRampShader?) to a raster? > > > > > > Howdy Benoit, > > First you will need to set the color shading algorithm for the raster, > >> YourRasterLayer.setColorShadingAlgorithm( "ColorRampShader" ) > This creates a new shader for the raster. > > Next you will need to build your color ramp (palette). This is just a > list of items of type QgsColorRampShader.ColorRampItem, Each item has > three variables, lable (QString), color (QColor) , and value (double) > > Once you have your list you will need to give that list to the shader. > >> YourRasterLayer.rasterShader().setColorRampItemList( YourColorRamp ) > > Then you need to set the color ramp type: > >> YourRasterLayer.rasterShader().setColorRampType( TheType ) > > Where TheType is, INTERPOLATED, DISCRETE or EXACT. If your color ramp > only had three entries: > Label1, Red, 0 > Label2, Yellow, 127 > Label3, Green, 255 > > exact - looks for an exact match at the time of shading, a value of 90 > would not be shaded. > > discrete - is a bin type approach, images pixels with values of 50, 70, > or 90 would all be assigned the same color > > interpolated - is as the name says, 90 will be an interpolated color > between Red and Yellow. In this case, more yellow than red as 90 is > closer to 127 than 0. > > > Hope that helps. > -pete > > -- > ==================================== > Peter J. Ersts, Software Developer > American Museum of Natural History > Center for Biodiversity and Conservation > Central Park West at 79th Street > New York, New York 10024 > Web: http://biodiversityinformatics.amnh.org > Web: http://cbc.amnh.org > > Open Source, > ...evolving through community cooperation to change the world bit by bit > > Quantum GIS Raster Development Team. > > _______________________________________________ > Qgis-developer mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/qgis-developer _______________________________________________ Qgis-developer mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-developer
