Hi,

Just a heads up that I pushed this to dev branch, and updated docs
(gdal_utilities and gdal_datamodel) as well as output of --formats and
--format commandline switches.

Cheers,
Etienne

On Sat, Jan 12, 2013 at 11:09 AM, Etienne Tourigny
<[email protected]> wrote:
> 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
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