Very nice example Tamas! In my opinion there is only one extra step needed; a no-color transparent section in the final image. Do you think this would also be possible?
2011/2/23 Tamas Szekeres <[email protected]>: > Daniel, > > Not sure if that fully satisfy with your requirements but I've already done > a similar task with the following steps: > > 1. Create a point data source (with attributes) from your points for example > by using ogr_vrt, something like: > > <OGRVRTDataSource> > <OGRVRTLayer name="mypoints"> > <SrcDataSource>ponts.csv</SrcDataSource> > <GeometryType>wkbPoint25D</GeometryType> > <GeometryField encoding="PointFromColumns" useSpatialSubquery="TRUE" > x="lon83" y="lat83" z="attribute"/> > </OGRVRTLayer> > </OGRVRTDataSource> > > 2. Use gdal_grid to create an interpolated grayscale image from the point > data dource. > > 3. To colorize the raster create (or compute) a LUT for each color band by > containing the following information: > > <LUT>[src value 1]:[dest value 1],[src value 2]:[dest value 2],...</LUT> > > A template of this vrt should look like this: > > <VRTDataset rasterXSize="{RASTERXSIZE}" rasterYSize="{RASTERYSIZE}"> > <VRTRasterBand dataType="Byte" band="1"> > <ColorInterp>Red</ColorInterp> > <ComplexSource> > <LUT>{LUT_RED}</LUT> > <SourceFilename>{SOURCEFILE}</SourceFilename> > <SourceBand>1</SourceBand> > <SrcRect xOff="{SRCXOFFSET}" yOff="{SRCYOFFSET}" xSize="{SRCXSIZE}" > ySize="{SRCYSIZE}"/> > <DstRect xOff="0" yOff="0" xSize="{RASTERXSIZE}" > ySize="{RASTERYSIZE}"/> > </ComplexSource> > </VRTRasterBand> > <VRTRasterBand dataType="Byte" band="2"> > <ColorInterp>Green</ColorInterp> > <ComplexSource> > <LUT>{LUT_GREEN}</LUT> > <SourceFilename>{SOURCEFILE}</SourceFilename> > <SourceBand>1</SourceBand> > <SrcRect xOff="{SRCXOFFSET}" yOff="{SRCYOFFSET}" xSize="{SRCXSIZE}" > ySize="{SRCYSIZE}"/> > <DstRect xOff="0" yOff="0" xSize="{RASTERXSIZE}" > ySize="{RASTERYSIZE}"/> > </ComplexSource> > </VRTRasterBand> > <VRTRasterBand dataType="Byte" band="3"> > <ColorInterp>Blue</ColorInterp> > <ComplexSource> > <LUT>{LUT_BLUE}</LUT> > <SourceFilename>{SOURCEFILE}</SourceFilename> > <SourceBand>1</SourceBand> > <SrcRect xOff="{SRCXOFFSET}" yOff="{SRCYOFFSET}" xSize="{SRCXSIZE}" > ySize="{SRCYSIZE}"/> > <DstRect xOff="0" yOff="0" xSize="{RASTERXSIZE}" > ySize="{RASTERYSIZE}"/> > </ComplexSource> > </VRTRasterBand> > <VRTRasterBand dataType="Byte" band="3"> > <ColorInterp>Alpha</ColorInterp> > <ComplexSource> > <LUT>{LUT_ALPHA}</LUT> > <SourceFilename>{SOURCEFILE}</SourceFilename> > <SourceBand>1</SourceBand> > <SrcRect xOff="{SRCXOFFSET}" yOff="{SRCYOFFSET}" xSize="{SRCXSIZE}" > ySize="{SRCYSIZE}"/> > <DstRect xOff="0" yOff="0" xSize="{RASTERXSIZE}" > ySize="{RASTERYSIZE}"/> > </ComplexSource> > </VRTRasterBand> > </VRTDataset> > > 4. Use the gdal vrt driver (and gdal_translate) to create the final image > (see an example attached). > > > Best regards, > > Tamas > > > > 2011/2/23 Daniel Cole <[email protected]> >> >> I am a new mapserver user and have spent countless hours over the last >> month reading, trying code, etc. before posting here for help. I am trying >> to generate an image (non-interactive) on a webpage based off of attribute >> data in a points file. For example, 20 different points equally distributed >> in a field contain data about the moister level of the soil. I want to make >> the lowest levels blue and the highest levels yellow, or something like that >> with some gradients in between. If possible I want it to have interpolated >> data between them to show the gradual change, but that isn't a must. I >> also want to wrap it in a polygon that trims the edges. >> I found some python code that I thought might do the trick , but it seems >> lots of heat maps are based off of how many points exist in a certain area, >> and thats now what I am doing. >> My points contain numbers in the attributes, 5, 25, 92, 71, etc. I feel >> like I am missing some easy way to do this right in front of me with gdal or >> something. If someone has any direction or even demo code that would be >> greatly appreciated. >> Thanks, >> >> Daniel >> _______________________________________________ >> mapserver-users mailing list >> [email protected] >> http://lists.osgeo.org/mailman/listinfo/mapserver-users >> > > > _______________________________________________ > mapserver-users mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/mapserver-users > > _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users
