Hi,
On the GDAL side there is the MajorObject class, which adds metadata to
GDAL classes and objects like Datasets. On OGR side there is no such
thing, AFAIK. Some OGR classes have a TestCapability method, which can
in principle support arbitrary capabilities, but there is no method,
which would return class or object related information.
For example a geotiff that I have returns four TIFFTAG_xxx keys and
respective values when I open it into a GDAL Dataset.
The reason I was looking for metadata method in OGR is that in some GUI
code I want to support generic and interactive creation of OGR
DataSources. For this purpose I've added to the OGR Driver class a
method DataSourceTemplate(1). This is in Perl code and outside of GDAL,
I use the Driver class from the bindings. The DataSourceTemplate method
returns a string, which can be used to create a dialog box for asking
arguments for the data source from the user. For example a GeoJSON
driver returns the string "<URL>[@<username>:][<password>]". This tells
the GUI code that a dialog box is needed which asks from the user a URL
and optionally username and password. Of course mostly the template is
simply <filename> and for database, GeoJSON, WFS and some other drivers
it is something else.
I was thinking that this kind of additional information would be best
available as metadata.
Any thoughts on these?
Ari
1)
https://github.com/ajolma/geoinformatica/blob/master/Geo-Vector/lib/Geo/Vector/Layer.pm
(from line 794 onwards)
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