Report hiearchical organization of vector layers #3762
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rouault
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Apr 29, 2021
rouault
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- Add C++, C, SWIG API to explore hiearchical organization of vector layers
- Implement it in FileGDB and OpenFileGDB drivers
- Make "ogrinfo my.gdb" use that
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CC @nyalldawson |
Nice enhancement! |
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One question -- if we add support in future for raster layers with a hierarchy, would we then add GDALGroupGetRasterLayerNames/ etc ? |
…and implement it in FileGDB/OpenFileGDB drivers Add GDALGroup::GetVectorLayerNames() and OpenVectorLayer(), and corresponding C and SWIG API Fixes https://trac.osgeo.org/gdal/ticket/5752
```
$ ogrinfo ../autotest/ogr/data/filegdb/featuredataset.gdb
INFO: Open of `../autotest/ogr/data/filegdb/featuredataset.gdb'
using driver `OpenFileGDB' successful.
Layer: standalone (Point)
Group fd1:
Layer: fd1_lyr1 (Point)
Layer: fd1_lyr2 (Point)
Group fd2:
Layer: fd2_lyr (Point)
```
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good question. For the very few drivers that support the multidimensional raster API, there is GDALGroupOpenMDArray() which returns a GDALMDArray which is a sort-of generalization of a GDALDataset to multidimensional (most things have an equivalent, but not always in a straightforward way). This is used for netCDF, HDF4, HDF5 and GRIB (and Zarr at some point). Hiearchical netCDF and HDF5 are represented like that. I can't really think of formats that would be 2D only and have a hierarchical organization, except some formulations of KML. Or possibly GeoPackage by adding an extension that would describe hiearchy. |
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Even, this is massive! Thanks so much for this! |
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@Saijin-Naib |
Fair enough. I tried experimenting to see if it's supported in gdb, but couldn't find any way to do this (see comment above), so I suspect it's not supported in geodatabases either. |
So, in FileGeoDataBase land, you want a Raster stored in a Feature Class? I think Feature Class can only hold vector, but there is the concept of Raster Catalogs, which may be a similar hierarchical structure in FileGeoDataBase. Don't let me go more than Wednesday without giving you data and answers. |
I believe they are closer in concept to a multidimensional raster array (mentioned earlier in this thread), but I've never used one personally to know for sure |
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GitHub_Test.gdb.zip I created a Raster Catalog, which doesn't allow for any hierarchical organization within itself, but it does present itself as a branch in the hierarchy of the FileGeoDataBase. |
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Hand-opening the .gdbtable file corresponding to the raster catalog, one can see a flat list of a few raster in it: Anyway, raster-in-gdb is something for later... |
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Hey @Saijin-Naib what is "parcel_fabric_test"? Is that some special kind of layer? |
Yeah, it's one of the number of special data types that can be stored only in Feature Dataset. If wanted, I'd like to enumerate a test dataset full of those special types. I included it here since it also presents itself as a branch in the hierarchical organization of the FileGeoDataBase |
A "DECadastralFabric": Interestingly the layers that in the screenshop appear under it have a path like \Feature_Dataset_Test\Parcel_Fabric_Test_Control , which is at the same level as the Parcel_Fabric_Test (\Feature_Dataset_Test\Parcel_Fabric_Test). I guess that ArcMap has a logic based on the fact that \Feature_Dataset_Test\Parcel_Fabric_Test is a prefix of the path of those layers. |
