[gdal-dev] OGR_Dr_Open deprecated

[Ari Jolma]

On 13.11.2015 15:58, Even Rouault wrote:
> Le vendredi 13 novembre 2015 14:48:02, Ari Jolma a écrit :
>> OGR_Dr_Open became deprecated in 2.0 but it is still the main method to
>> open vector datasets in the bindings.
>>
>> I just realized that I would need one method to open all data sets.
>> OpenEx seems to be it but I would still need to cast the object into a
>> Dataset or a DataSource.
> Just don't cast. You can use a Dataset for all purposes since the OGR_DS_XXXX
> API has been transposed to GDALDatasetXXXX and is already available in
> GDALDatasetShadow

Swig imposes typechecks that prevent that. It is like with the GDALGrid, 
which takes a vector dataset. I had to write an explicit cast function 
for DataSource object into a Dataset object. Which I now realize is 
probably not safe since there is an explicit warning against that in the 
docs.

>
>> Maybe OpenEx should be the preferred way to
>> open any data set also with the bindings.
>>
>> However, I don't seem to find good way to tell whether the data set
>> object OpenEx gives me is a raster or a vector. Is there such?
> If you open with OpenEx(filename, OF_VECTOR), so read-only + vector, then the
> few drivers that support vector and raster will return NULL if the dataset has
> no vector data and just raster. If you open with OpenEx(filename, OF_VECTOR |
> OF_UPDATE) and they support update mode, then they will return non-NULL even
> if the dataset has no vector data. A robust way of checking if there's vector
> data is to check GetLayerCount() != 0.

Thanks.

I have so far ignored the OpenEx method. I'll develop it so in the Perl 
bindings that it will return a raster dataset object or a vector data 
set object depending whether the returned handle is raster or vector. 
I'll also deprecate the old Open methods in the Perl bindings.

Ari

>
> Even
>