Thanks, Frank. I understand the purist argument against this, though I think that 90% of the time you can look at a connection string for a data source and determine what the output driver should be. I'd like to see this feature in the future, but I understand that it would need a caveat that it may not always work or return the expected result. Maybe a "GuessOutputDriver(...)" function would be the appropriate way to name it.
On Wed, Oct 6, 2010 at 8:47 AM, Frank Warmerdam <[email protected]> wrote: > Joel Odom wrote: > >> Is there a canonical way to pick an OGR driver based on a file name or on >> a generalized connect string? (For example, if the file name ends in >> ".shp", it would select the Shapefile driver.) Thanks. >> > > Joel, > > No. > > I really wanted to send this out with just that one word answer, but I > can't help myself but elaborate. > > First, I think file format identification based on filename extension is > a terrible idea, and I curse those operating systems that try to build it > into the graphical shell. Likewise a pox on applications that carry on > this tradition. > > Second, there are a number of OGR file formats that have no dependency on > extension. For example GML, DGN, DXF, PCIDSK. For these formats any > extension is fine and only letting people pick a file if it has some > particular is offensive to me. > > Third, there are lots of database connection formats that aren't extension > based. Typically these can be identified based on a prefix string like > MYSQL: though not always. > > Despite my feelings on this matter, on the GDAL side of the house we > actually > provide a metadata item on drivers allowing specification of a preferred > extension which applications can use. We also have an "identify" mechanism > that will try to efficiently identify what format a file or dataset name > string is without necessarily actually opening it. > > Unfortunately, the OGR world is less sophisticated in this regard and lacks > these two mechanisms. This is one reason I'd like to have a "grand > unification" of GDAL and OGR one day. > > Best regards, > -- > > ---------------------------------------+-------------------------------------- > I set the clouds in motion - turn up | Frank Warmerdam, > [email protected] > light and sound - activate the windows | http://pobox.com/~warmerdam > and watch the world go round - Rush | Geospatial Programmer for Rent > > -- http://www.operationliberate.com/
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