Jody Garnett ha scritto: >> The coordinate sequence position is the most promising imho, >> as the transformation code has to deal with it anyways, >> and it can compare the cs dimension with the srs one and >> learn it has to play the "copy coordinates beyond the first >> two over" trick. > > I like that alternative; it is "closer" to the data leaving us less > chance for errors then a hint. I hope it also limits the amount of > work you need to do.
I've thought more about this issue. The cs dimension covers the data path well enough, but does not cover the metadata path that is used by: - configuration tools (how do you know the feature type is 3d?) - createSchema (how do you tell the postgis datastore that you want to create a 3d system?) The second case is obvious. The first one is about knowing and eventually overriding. Point in case, I know that the "tasmania roads" shapefile we ship with GeoServer is actually a arcz with all the heights being equal to 0 (noticed it when trying, and failing, to import it into Oracle). Now, what if GeoServer from one day to the next starts returning 3d gml, and the admins do not want that? We'd also need some way to override this (FEATURE_2D hint) but we also need a way to just communicate this without actually reading the data (e.g., the postgis tables might be there and empty). If we follow the approach above, the coordiantesequence dimension is available only as lons as we have data. What about metadata? We'd need some information in the GeometryDescriptor I believe. Granted, CRS is available in both places, but I'm not seeing any sane path to add this extra, override information into it, without breaking its API and requiring quite some changes in the referencing subsystem at the same time. Too bad CRS does not have a mutable user data map... Any bright idea here? (I know I already said no to this, yet I said no to the only way I can imagine this implemented. If you have any smarter path, please share). Cheers Andrea -- Andrea Aime OpenGeo - http://opengeo.org Expert service straight from the developers. ------------------------------------------------------------------------------ Register Now & Save for Velocity, the Web Performance & Operations Conference from O'Reilly Media. Velocity features a full day of expert-led, hands-on workshops and two days of sessions from industry leaders in dedicated Performance & Operations tracks. Use code vel09scf and Save an extra 15% before 5/3. http://p.sf.net/sfu/velocityconf _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
