Hi my mentors, Sorry – this one is long. In recent days I've played with JAI's WarpGrid transformation. I've made a WarpGridTransform2D that extends existing WarpTranform2D and it just encapsulates the JAI parameters and constructors into the GeoTools transformation's conventions. Finally I've wrote the WarpGridBuilder that generates the WarpGridTransform2D from MappedPositions and another parameters. To be clear the steps goes like this:
1) From irregular MappedPositions I generate regular grid where user can specify the grid steps (for example 10 km). This grid is generated by inverse distance weighted interpolation and in next weeks I'll try another algorithms. 2) From this grid there is WarpGridTransform2D that uses JAI's Grid Warp as described here: http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Geom-image-manip.doc.html So it means that it is combination of some general algorithm like IDW interpolation that presents some kind of control grid. and final billinear interpolation preformed in JAI's GridWarp that transforms the points within the grid cells generated by previous method. I'm having simple demo that generates me randomly warped photos - looks really funny. However this part seems to work (somehow) few questions remains: The little problem is that I have to transform all of input values (envelope and mapped positions) from 'real world' coordinates into the 'grid coordinates'. Nowadays I'm doing it inside WarpGridBuilder, but maybe some more sophisticated approach should be made. Problem is that every system is haveing different axis direction an transformation of envelope so transformed envelope.LowerConner dosn't mean the grid start values in general. Another question is that I'm using Factory to get WarpGridTransform2D parameters: WarpGridParameters = factory.getDefaultParameters("WarpGrid"); but since I'm working in separate project haveing GeoTools like a dependency I don't know how to do this without editing the GeoTools file with MathTranformProviders. I've also submitted the abstract for FOSS4G about our work (hope that it will be accepted). Thanks for your help! Cheers, Jan. P.S. Hi Jesse, and welcome after your 'vocation' :-) . I hope you've enjoyed Europe! ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
