[gdal-dev] Issues with WFS driver

[Ari Jolma]

On 05/25/2013 12:37 PM, Even Rouault wrote:
> If you output to a regular file, the GML driver will generate a .xsd 
> file with the schema alongside the GML file. If you output to 
> /vsistdout/ directly, then of course it is not possible to generate 
> the .xsd file. If you don't want to write on the filesystem, an 
> alternative would be to output to /vsimem/ so that you can read both 
> files afterwards. Another way if you want to use the .xsd generated by 
> the GML driver and keep the advantage of using streaming to vsistdout, 
> would be to: 1) Output to /vsimem/ , create the layer definition, but 
> write 0 feature. You just fetch the .xsd that can be used for 
> DescribeFeatureType 2) Output to /vsistdout/ with all the needed 
> features. 

so, if I understand correctly:

my $postgis = Geo::OGR::Open($Datasource);
my $postgis_layer = $postgis->Layer($Name);

my $vsi = '/vsimem/';
my $gml = Geo::OGR::Driver('GML')->Create($vsi, {
     TARGET_NAMESPACE => 'http://www.opengis.net/wfs', PREFIX => 'wfs' });
my $gml_layer = $gml->CreateLayer($Name);

my $schema = $postgis_layer->GetLayerDefn;
for my $i (0..$schema->GetFieldCount-1) {
     $gml_layer->CreateField($schema->GetFieldDefn($i));
}

# at this point there should be a .xsd in /vsimem/, which could/should 
be used for the DescribeFeatureType request

I'll try this later. Now I'm happy with the hack.

Ari