Farrukh Najmi wrote: > Thanks Jody for the very helpful response. No worries; now if you can tell me where to put that information in the user guide for the next person we will be ahead of the game :-) Where would you look ... > I am unclear about one important conceptual understanding though. You > said that "JTS does not care (or use) the SRID value". So what does > JTS use for its internal CoordinateReferenceSystem? Does that mean > that before geometry objects are stored using JTS they are normalized > to that JTS internal CoordinateReferenceSystem? How else could JTS do > spatial operations on geometry objects that use different SRID values? Just so; there is a JTS utility class here to help you reproject your JTS Geometry into the CoordinateReferneceSystem of your choice. - http://docs.codehaus.org/display/GEOTDOC/02+JTS+Utility+Class > Said another way, geotools allows apps to use a large number of > CoordinateReferenceSystems among different geometry objects. I had > assumed JTS did the same and the only difference between the two was > use of SRID vs. CoordinateReferenceSystem with some mapping between > the two. Your statement "JTS does not care (or use) the SRID value" > puts in doubt my understanding of how CoordinateReferenceSystems are > handled in the two libraries. JTS does the mathematical "topology part"; see this page: http://docs.codehaus.org/display/GEOTDOC/Point+Set+Theory+and+the+DE-9IM+Matrix GeoTools does the mathematical "referencing part", and the features, and the rendering and the xml and the database access and the .... well we try and get the job done.
Cheers, Jody ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Geotools-gt2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
