KML output format?

[Frank Warmerdam]

Daniel Morissette wrote:
> I thought about an OGR driver too, that would be very useful in several 
> situations but I had come back to the direct KML output format option 
> since that seemed simpler to implement.

Daniel,

I agree.

> Unfortunately for the KML case using OGR to generate the output would 
> not allow us to easily apply styles (colors, symbols) to the shapes. We 
> would probably need to generate OGR style strings in MapServer to pass 
> to the driver and extend the OGR-KML driver to support style strings (I 
> assume it doesn't at the moment). There is also the overhead of having 
> OGR write the output to disk and then having MapServer read and return 
> the contents of the output. 

For some drivers (going through VSI*L functions) the output could be
to memory, and then that could be spooled back to stdout after completion.

 > Also what to do with formats that generate
> multiple files (e.g. shapefiles, TAB datasets, etc.)? Should MapServer 
> zip them up before returning them? And if yes how does MapServer know 
> exactly which files to include in the ZIP for each OGR output format? 
> Actually, how is this handled at the moment with GDAL output formats?

This is tricky.  Currently MapServer GDAL output just doesn't support
multi-file formats.  It is my hope to rectify this at some point. It is
a bigger issue for OGR where some key formats (shape, mapinfo) are
multi-file formats.

> An OGR output driver is definitely feasible and means more reusability, 
> but that's also more involved than a direct KML output format 
> implementation, that's why that was not my preferred option initially.

Agreed

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org