5 Model Generalization
103
we would then have a WFS-R (progressive refinement WFS) with an extra GetFeatureByImportance request and two parameters minImp and maxImp to specify the
importance range of the features to be selected. When no value is specified for these
parameters, all features are requested, but still in order of importance from high to
low. And when minImp = maxImp exactly that importance level is requested, as a
‘slice’ of the data set (first query in Sect. 5.5.1). The HTTP Post request would then
look like this (the ‘D’ in the ogc:SortBy is for ‘descending’):
gdmc:geom
136931,416574 139382,418904
gdmc:imp_high D
The WFS will give a GML stream of vector data as output. To encode the components of the tGAP structure in GML, the standard GML 3 geometry and topology classes can be used without a problem, maybe with one exception: because
of the constraint in the GML topology model that each gml:Edge should have 2
gml:directedNodes (see fragment below), also exactly two nodes per edge must be
in the output GML. In the tGAP model an edge does not have start- and end-nodes:
only the corresponding BLG-tree has start- and end-nodes.
103
we would then have a WFS-R (progressive refinement WFS) with an extra GetFeatureByImportance request and two parameters minImp and maxImp to specify the
importance range of the features to be selected. When no value is specified for these
parameters, all features are requested, but still in order of importance from high to
low. And when minImp = maxImp exactly that importance level is requested, as a
‘slice’ of the data set (first query in Sect. 5.5.1). The HTTP Post request would then
look like this (the ‘D’ in the ogc:SortBy is for ‘descending’):
The WFS will give a GML stream of vector data as output. To encode the components of the tGAP structure in GML, the standard GML 3 geometry and topology classes can be used without a problem, maybe with one exception: because
of the constraint in the GML topology model that each gml:Edge should have 2
gml:directedNodes (see fragment below), also exactly two nodes per edge must be
in the output GML. In the tGAP model an edge does not have start- and end-nodes:
only the corresponding BLG-tree has start- and end-nodes.