Hi Jukka, On Tue, Nov 17, 2020 at 2:57 AM jratike80 < jukka.rahko...@maanmittauslaitos.fi> wrote:
> Hi, > > I have done some helpdesk work within the GDAL community and I know well > that the open options and config options are confusing. I also know that > they exists for a reason but simplified and uniform way to use them would > be > nice. > I'm glad to read that you're interested! I believe there is tension between simple and uniform and we'll need wide input to find a good balance. I've been using QGIS today for the first time in a while and I think that application could benefit from this as well. A "URL" for datasets could remove some of the complexity of QGIS dialog boxes for creating or configuring connections. > Some comments on comments: > > >> gdalinfo my.tif -oo GEOREF_SOURCES=WORLDFILE,PAM > >> > > > Ideally this would be baked into the format, but, yes, I think we've got > a > > bead on dataset open options. > > I don't know how it could be baked into the format. The option gives user > an > option to override wrong GeoTIFF georeferencing with wordfile, for example. > Yes. > >> gdalinfo BAG:"data/test_vr.bag":supergrid:0:1 > >> > > > DRIVER:"file":something > > > Right. This will require some work because of multiple colons. Though > I've > > never seen BAG driver data in the wild. Is this a real live format? > > As far as I know BAG is the hdf of bathymetry and widely used in that > context. > > >> gdalinfo data/test_vr.bag -oo MODE=RESAMPLED_GRID -oo > SUPERGRIDS_MASK=YES > >> gdalinfo HDF5:"d:\foo.he5"://HDFEOS/SWATHS/foo/bar > >> > > > HDF5 driver, filename using Windows drive, and UNC path within it. This > is > > marginal, right? > > The part beginning with // is not UNC path but the name of the subdataset > within hdf5 file https://gdal.org/drivers/raster/hdf5.html. Not more > marginal than HDF5 itself. > > Thank you for explaining. > >> ogrinfo OCI:warmerda/password@.dreadfest > > >Wat? > > Text has just been formatted into email link because of the @ sign that > belongs to the Oracle connection string "username" / "password" @ "the name > of the Oracle database as it appears in the tnsnames.ora file". Let's see > if > formatting happens again when I send this from Nabble: > > OCI:warmerda/passw...@gdal800.dreadfest.com abc.shp > Thanks. > -Jukka Rahkonen- > > > > > Sean Gillies-3 wrote > > Hi Even, > > > > On Wed, Nov 4, 2020 at 9:01 AM Even Rouault < > > > even.rouault@ > > > > > > wrote: > > > >> > > Another particularity we have in GDAL is that the dataset name might > >> be > >> > > almost > >> > > anything. Most of the time, it is a regular file path, or some /vsi > >> path. > >> > > But > >> > > sometimes, it can be JSON content (the GeoJSON driver accepts the > >> content > >> > > to > >> > > be directly provided as the dataset name), or XML (VRT, WMS > drivers). > >> > > We have also the subdataset syntax "HDF5:foo.hdf:my_variable" > >> > > >> > Could VRT XML and JSON be exempted? We already have a way to embed > open > >> > options in the XML. > >> > >> If the gdn: mechanism is a new possibility offered that doesn't exclude > >> existing ones (otherwise that would be a pretty big breaking change), we > >> could > >> possibly exempt the odd cases I mentioned (or have some quoting/escaping > >> rules > >> to enable that payload to be seen as a file), which generally don't need > >> a > >> "permanent" way of refering to the dataset like gdn: would offer, since > >> this > >> is content often generated programatically or retrieved dynamically. > >> > >> Covering subdataset would be a more important use case. Something that > >> would > >> have to be decided if the way we express subdatasets would be somehow > >> standardized or if it would be a black-box string for the gdn: > >> encapsulation. > >> For a black-box approach, we would have to define some escaping/quoting > >> rules > >> to avoid any potential issue with separators of the gdn syntax. If we > >> decide > >> that the subdataset syntax is part of what is standardized by GDN that > >> would > >> be a more challenging exercice, because the subdataset syntax varies > from > >> driver to driver. > >> > > > > The variation of subdataset syntax among drivers is a bug, let's try to > > fix > > this. > > > > It seems to me that the internet way to address subdatasets would be to > > use > > a # URL fragment. But since most of our formats and the servers that > serve > > files of these formats are not aware, we may have to come up with > > something > > different. We may need to consider making subdatasets a layer opening > > option? > > > > pending on how we design things, that might impact between: > >> - just GDALOpen() generic code if GDALOpen() decodes the gdn: string to > >> decompose it into 'classic' dataset names and open options > >> - all drivers if the gdn: string would be passed to each > >> GDALDriver::pfnOpen() > >> implementation > >> - intermediate situation if we decide to drop (at least for future > >> drivers) > >> per-driver subdataset syntax (which has deficiencies has the quoting > >> rules > >> to > >> separate the filename from the non-filename component vary from driver > to > >> driver, and are most of the time not defined) to come up with something > >> more > >> standardized > >> > >> To help brainstorming, a non-exhaustive overview of a few situations > >> mixing > >> driver prefixing, subdataset syntax and open options: > >> > >> gdalinfo my.tif > >> > > > > Yes. We have to handle bare paths to local dataset files. > > > > > >> gdalinfo my.tif -oo GEOREF_SOURCES=WORLDFILE,PAM > >> > > > > Ideally this would be baked into the format, but, yes, I think we've got > a > > bead on dataset open options. > > > > > >> gdalinfo GTIFF_DIR:0:d:\my.tif > >> > > > > WTF is this? :) > > > > > >> gdalinfo EEDAI:my/asset > >> gdalinfo EEDAI: -oo ASSET=my/asset > >> gdalinfo EEDAI:my/asset:band1, band2 > >> gdalinfo EEDAI: -oo ASSET=my/asset -oo BANDS=band1,band2 > >> > > > > Never seen these. > > > > > >> gdalinfo BAG:"data/test_vr.bag":supergrid:0:1 > >> > > > > DRIVER:"file":something > > > > Right. This will require some work because of multiple colons. Though > I've > > never seen BAG driver data in the wild. Is this a real live format? > > > > > >> gdalinfo data/test_vr.bag -oo MODE=RESAMPLED_GRID -oo > SUPERGRIDS_MASK=YES > >> gdalinfo HDF5:"d:\foo.he5"://HDFEOS/SWATHS/foo/bar > >> > > > > HDF5 driver, filename using Windows drive, and UNC path within it. This > is > > marginal, right? > > > > > >> gdalinfo netCDF:"/vsicurl/http://example.com/my.nc":my_var > >> > > > > This looks less complicated than some of the examples above. > > > > > >> ogrinfo "PG:dbname=testdb user=foo" > >> ogrinfo "mySQL:testdb,user=foo" > >> > > > > These seem like they could be driver specific, but generalized key-value > > parameters. > > > > > >> ogrinfo OCI:warmerda/ > > > password@.dreadfest > > > > > > > Wat? > > > > > >> GDALOpen() is not even aware that HDF5:bla means that the dataset will > be > >> recognized by the HDF5 driver > >> > >> > > Wait what? > > > > -- > > Sean Gillies > > > > _______________________________________________ > > gdal-dev mailing list > > > gdal-dev@.osgeo > > > https://lists.osgeo.org/mailman/listinfo/gdal-dev > > > > > > -- > Sent from: http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/gdal-dev -- Sean Gillies
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