Hi, I'd like to add my use case:
A user adds a layer that has not projection defined. So I set the projection to be Generic so that it is will not be transformed. Next a second layer is added. The layer is in the same projection but has a projection defined. Given the current implementation the first layer always disappears because it is transformed to lat/long irregardless of the fact that the second layer is the same projection. The expected behaviour is both layers are displayed. Jesse On 12-Jun-08, at 10:46 AM, Martin Desruisseaux wrote: > Jess Eichar has raised an issue with > DefaultEngineeringCRS.GENERIC_2D. Basically he would like any call > to CRS.findMathTransform(sourceCRS, targetCRS) to return the > identity transform if at least one argument is a GENERIC_2D. > > The current behavior is "go as far as possible. When you can't > transform further, return the chain you got so far rather than > throwing an exception". The rational behind this behavior is that > GENERIC_2D is not UNKNOWN_2D: it explicitly defines a cartesian > space and axis in (x,y) order and in metres: > > http://javadoc.geotools.fr/snapshot/org/geotools/referencing/crs/DefaultEngineeringCRS.html#GENERIC_2D > > So if a conversion from foots to metres is possible, if axis > swapping from (y,x) to (x,y) order is possible, or if some > transformation from non-cartesian space to a cartesian space is > possible, we problably expect those transformations to be applied > given the current GENERIC_2D definition (I'm not sure they are > properly performed in current implementation - the behavior reported > by Jesse looks like a bug - but this is the idea). > > So if a CRS is totally unknown, GENERIC_2D is probably not > appropriate since it implies that you known that the CRS is > cartesian, etc. > > How peoples use GENERIC_2D? Is it in the sense ot "totally unknown > CRS", or in the sense of "unknown CRS having (x,y) axis order in > metres"? > > Martin ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
