Hi Ivan it seems to me like the GeoRasters is somewhat special, but I think it warrants flagging it as supporting subdatasets regardless.
A generic example is the netcdf driver, which supports subdatasets when a given netcdf file contains several variables, which can have different CRSs. Each variable is a distinct subdataset, which can be each be accessed separately. cheers Etienne On Fri, Jan 11, 2013 at 1:18 PM, Ivan Lucena <[email protected]> wrote: > Hi Etienne, > > It sounds like a good idea to add that information to the GDALDriver metata. > I can see how one could take advantage of that feature when writing a generic > solution to deal with all SUBDATASETS drivers at once. > > But I am wondering if I should add that to the GeoRaster driver. This driver > only reports SUBDATASETS if the result of the query is not an unique > SDO_GEORASTER object. > > So for example, if you use an WHERE clause that result in several objects, > each object is reported as a SUBDATASET. That is how the QGIS Oracle Raster > extension can browse into tables and columns to list existing images. See > http://gdal.org/frmt_georaster.html "Browsing the database for GeoRasters". > > In that case the SUBDATASET is not a property of the driver, but the > GDALDataset. I believe that others SUBDATSET supporters driver also do some > similar, or maybe is gdalinfo who does that. If there is just one SUBDATASET > the report shows one Dataset, with Rows and Columns other than 512x512 and > the info from the "first and only" SUBDATASET. > > Anyway, I always thought that the SUBDATASET were kind of a abstraction leak > into the GDAL data model. They showed up later in the game and what we have > is just an adaptation to make it work. It might be something to re-think for > GDAL 2.0. IMHO. > > Regards, > > Ivan > > > > > > > > -------Original Message------- > From: Etienne Tourigny > To: Even Rouault > Cc: gdal-dev > Subject: Re: [gdal-dev] which formats support subdatasets? > Sent: Jan 11 '13 08:23 > > On Fri, Jan 11, 2013 at 11:03 AM, Even Rouault > <[LINK: [email protected]] > [email protected]> wrote: > > Selon Etienne Tourigny <[LINK: [email protected]] > [email protected]>: > > > >> Hi, > >> > >> I'd just like to point out a patch I have submitted to report which > >> raster drivers support subdatasets, using the DMD_SUBDATASETS metadata > >> item. > >> I have also modified gdalinfo and format docs. > >> > >> [LINK: http://trac.osgeo.org/gdal/ticket/4902] > http://trac.osgeo.org/gdal/ticket/4902 > >> > >> For example: > >> > >> $ gdalinfo --format hdf4 > >> Format Details: > >> Short Name: HDF4 > >> Long Name: Hierarchical Data Format Release 4 > >> Extension: hdf > >> Help Topic: frmt_hdf4.html > >> Supports: Subdatasets > >> > > > > I've looked at the patch and it seems good. I'm not sure I would have > added a > > new column in the table, but if you think it is usefull, keep it. It > would > > perhaps be good to mention in gdal_datamodel.dox, in the SUBDATASETS > section, > > that drivers that support them advertize the DMD_SUBDATASETS > capability. And I > > think that swig/include/gdalconst.i should also be edited to add the > new > > constant. After that please commit. > > I though adding the info to frmt_various.html was the most > appropriate, but it is a bit intrusive. Should it be elsewhere, like > the individual driver docs or in gdal_datamodel? > > I also though about adding an "s" key to the output of "--formats" > format support string e.g. (rw+vs) > > I'll make the other changes you suggest. > > > > > I'm not sure it is appropriate to backport in 1.9 however (new feature, > output > > of gdalinfo --format modified). 1.10 should be out soon hopefully. > > I also don't think it's appropriate adding this to 1.9 > > > > >> > >> Regards, > >> Etienne > >> > >> On Tue, Nov 20, 2012 at 10:43 AM, Etienne Tourigny > >> <[LINK: [email protected]] > [email protected]> wrote: > >> > Hi > >> > > >> > I'd like to be able to identify which raster and vector formats > >> > support subdatasets (or multipl layers). > >> > > >> > A quick grep search (grep SUBDATASETS frmts/*/*.cpp) showed which > GDAL > >> > drivers can report subdatasets. > >> > Am I missing something? > >> > > >> > I think it would be nice to include this info in the driver summary > >> > page - should I just edit the html or is there some other file to > >> > edit? > >> > > >> > I was wondering how to find that out for OGR drivers - or do all > >> > drivers support multiple layers in one datasource? > >> > > >> > > >> > Regards, > >> > Etienne > >> _______________________________________________ > >> gdal-dev mailing list > >> [LINK: [email protected]] > [email protected] > >> [LINK: http://lists.osgeo.org/mailman/listinfo/gdal-dev] > http://lists.osgeo.org/mailman/listinfo/gdal-dev > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > gdal-dev mailing list > [LINK: [email protected]] [email protected] > [LINK: http://lists.osgeo.org/mailman/listinfo/gdal-dev] > http://lists.osgeo.org/mailman/listinfo/gdal-dev _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
