Hi, today I was trying to create a process that would make up for some limitations of the WFS GetFeature operation, in particular the inability to compute on the fly new attribute. I'd like to be able to define new attribute in the returned collection as:
<ecql expression> as newname There is however a big catch in all of this: how do I create the target schema? I know the new attribute name, but not its type. For example, given: buffer(the_geom, 20) as bufferedgeom how do I get to know it's going to be a Geometry? The filter function implementations offer nothing about their return type. And, correct me if I'm wrong, without a proper schema it's not possible to drive a xml encoding or a shapefile encoding. A silly approach could be to run the new attributes against the first feature and see what type the transformed object is, but that would fall apart if the_geom is null for that attribute. Or one could make it go through all of the input features, serialize the results to avoid recomputing it, and try to summarize the result type by inspection of all results. Which would still fail if all of the attributes involved in the transformation are null... Hmmm.... bright ideas, suggestions? Cheers Andrea ------------------------------------------------------------------------------ The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://ad.doubleclick.net/clk;226879339;13503038;l? http://clk.atdmt.com/CRS/go/247765532/direct/01/ _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
