AsGML: use posList with attribute rather than coordinates tag

[aperi2007]

In the GML generated from AsGML() I guess is better use the posList rather than coordinates (deprecated).

so instead of <gml:curveProperty> <gml:LineString srsName="EPSG:3003"> <gml:coordinates>1 4, 4 6,… </gml:coordinates> </gml:LineString> </gml:curveProperty>

is better:

<gml:curveProperty> <gml:LineString srsName="EPSG:3003"> <gml:posList srsDimension="2">1 4 4 6… </gml:posList> </gml:LineString> </gml:curveProperty>

please note the posList is with the attribute srsDimension to give the dimension and without comma separating the coordinates.

[strk]

Uhm, topology.AsGML is using the underlying ST_AsGML(geometry) for the components. These are the ST_AsGML outputs for GML version 2 and GML version 3:

=# select st_asgml(2,'LINESTRING(0 0, 10 0)'::geometry);
                                   st_asgml                                   
------------------------------------------------------------------------------
 <gml:LineString><gml:coordinates>0,0 10,0</gml:coordinates></gml:LineString>
(1 row)

and

=# select st_asgml(3,'LINESTRING(0 0, 10 0)'::geometry);
                                   st_asgml                                   
------------------------------------------------------------------------------
 <gml:Curve><gml:segments><gml:LineStringSegment><gml:posList srsDimension="2">0 0 10 0</gml:posList></gml:LineStringSegment></gml:segments></gml:Curve>
(1 row)

Does the LineString-posList version you suggest correspond to another version ?

[aperi2007]

I tested with the xsd of GML 3.1.1.

Under a TopoCurve is mandatory a directedEdge. under the directedEdfge the only choice is Edge with the two directedNode. under the Edge because the choice is "curveProperties" under a curveProperties in a TopoCurve the only choice availables are: CompositeCurve, OrientableCurve, Curve and LineString

so the logical choice is "LineString".

There isn't the option of "LineStringSegment". That instead is good for the MultiCurve tag od type simplefeature (not for the topology "TopoCurve").

[aperi2007]

I check better. Is possibile to use the LineStringSegment, but using a sub-part of what generated from ST_AsGML(3). Infact the structure is like this:

<gml:TopoCurve>

<gml:directedEdge>

<gml:Edge gml:id="Edge_2_192278">

<gml:directedNode orientation="-">

<gml:Node gml:id="Node_1_242975" />

</gml:directedNode> <gml:directedNode>

<gml:Node gml:id="Node_1_243597" />

</gml:directedNode> <gml:curveProperty>

<gml:Curve>

<gml:segments>

<gml:LineStringSegment>

<gml:posList srsDimension="2">…</gml:posList>

</gml:LineStringSegment>

</gml:segments>

</gml:Curve>

</gml:curveProperty>

</gml:Edge>

</gml:directedEdge>

</gml:TopoCurve>

This version is better because allow even the description of multiparts repeating the LineStringSegments. Like this

<gml:TopoCurve>

<gml:directedEdge>

<gml:Edge gml:id="Edge_2_192278">

<gml:directedNode orientation="-">

<gml:Node gml:id="Node_1_242975" />

</gml:directedNode> <gml:directedNode>

<gml:Node gml:id="Node_1_243597" />

</gml:directedNode> <gml:curveProperty>

<gml:Curve>

<gml:segments>

<gml:LineStringSegment>

<gml:posList srsDimension="2">…</gml:posList>

</gml:LineStringSegment> <gml:LineStringSegment>

<gml:posList srsDimension="2">…</gml:posList>

</gml:LineStringSegment> <gml:LineStringSegment>

<gml:posList srsDimension="2">…</gml:posList>

</gml:LineStringSegment>

</gml:segments>

</gml:Curve>

</gml:curveProperty>

</gml:Edge>

</gml:directedEdge>

</gml:TopoCurve>

Regards

[strk]

As of r6691 I've switched topology.AsGML to use GML3 for the curveProperty of Edges and pointProperty of Nodes.