OSGeo
ogrinfo: auto-select layer in datasets with only one layer
What does this PR do?
Avoids the need to specify the layer name in ogrinfo calls to single-layer datasets, e.g.
ogrinfo -so tl_2022_us_county.shp
instead of
ogrinfo -so tl_2022_us_county.shp tl_2022_us_county
This matches the behavior when using ogrinfo -json or when calling gdal.VectorInfo from Python. It is also described as "likely what is really wanted" by the author 17 years ago :)
Somewhat mixed feelings about this because forgetting -al is my reminder to also set -so. But I don't think that's a good reason to keep the current behavior (though there may be one).
What are related issues/pull requests?
Tasklist
- [ ] Review
- [ ] Adjust for comments
- [ ] All CI builds and checks have passed
Does the change mean that number of layers is checked first and if the dataset has only one layer, then ogrinfo comes automatically for that layer, and otherwise user gets a list? And all the open options etc are still checked, for example "list_all_tables" https://gdal.org/drivers/vector/gpkg.html#dataset-open-options.
The change may make some issues if users learn to run plain ogrinfo my.gpkg or ogrinfo my.gml in some odd scripts using GDAL utilities and parsing and piping the response. The script stops working when another layer is added to the dataset.
I'm also ambivalent about the appropriateness of the change, which has some niceness, but might make things harder to reason about. Currently, you have 3 graduation of details about dataset exploration:
- ogrinfo my.gpkg: just list layer names and geometry type
- ogrinfo -so -al my.gpkg: metadata of all layers
- ogrinfo -al my.gpkg: metadata + features Perhaps the documentation is not obvious / clear enough about that
