[mapserver-users] Geojson output from WFS is missing ID

[Even Rouault]

Le mardi 10 mai 2016 12:32:17, Rahkonen Jukka (MML) a écrit :
> Hi,
> 
> Do you mean that the output from GeoServer WFS 2.0 is not valid because it
> does not seem to have gml:id for the collection, nor for the geometries,
> but it does have gml:id for the members?
> 
> <wfs:FeatureCollection numberMatched="49" numberReturned="49"
> timeStamp="2016-05-10T10:23:29.813Z"
> xsi:schemaLocation="http://www.opengis.net/wfs/2.0
> http://localhost:8080/geoserver/schemas/wfs/2.0/wfs.xsd
> http://www.openplans.org/topp
> http://localhost:8080/geoserver/wfs?service=WFS&version=2.0.0&request=Desc
> ribeFeatureType&typeName=topp%3Astates http://www.opengis.net/gml/3.2
> http://localhost:8080/geoserver/schemas/gml/3.2.1/gml.xsd"><wfs:member><to
> pp:states gml:id="states.1"><topp:the_geom><gml:MultiSurface
> srsName="urn:ogc:def:crs:EPSG::4326"
> srsDimension="2"><gml:surfaceMember><gml:Polygon><gml:exterior><gml:Linear
> Ring><gml:posList>

Yes, this will not validate the gml 3.2.1 schema. See for example 
http://www.datypic.com/sc/niem21/e-gml32_MultiSurface.html
gml:id being compulsory on geometries is one of the main difference between gml 
3.2 and 3.1

> 
> -Jukka Rahkonen-
> 
> Even Rouault wrote:
> > Le mardi 10 mai 2016 12:08:07, Rahkonen Jukka (MML) a écrit :
> >> Hi,
> >> 
> >> WFS output from Mapserver 7.0 in GML contain gml:id
> >> <ms:msGeometry><gml:Polygon gml:id="states.1"
> >> srsName="urn:ogc:def:crs:EPSG::4326">
> > 
> > It looks like you must use WFS 2.0 and/or GML 3.2 output. In that case
> > the GML
> 
> 3.2 schemas require each geometry to have a gml:id. So this is a geometry
> id, not a feature id ( in case of geometry collections, you'll have one id
> for the collection and as many ids as members) To address that technical
> requirement, MapServer generates it in a sequential way for the output of
> each request. Not completely sure it matches the uniqueness intended but
> at least it validates schemas. So this particular one is not a good
> candidate to be exported to other formats, but I see Thomas has just
> replied for the feature id.
> 
> >> However, with GeoJSON as outputformat the id is missing:
> >> {
> >> "type": "FeatureCollection",
> >> "crs": { "type": "name", "properties": { "name":
> >> "urn:ogc:def:crs:OGC:1.3:CRS84" } }, "features": [ { "type":
> >> "Feature", "properties": { "PK_UID": 1, "STATE_NAME": "Illinois",
> >> 
> >> 
> >> GeoJSON specification says in
> >> http://geojson.org/geojson-spec.html#feature-objects: "If a feature
> >> has a commonly used identifier, that identifier should be included as
> >> a member of the feature object with the name "id"."
> >> 
> >> GeoJSON from Geoserver WFS does contain the id:
> >> 
> >> {"type":"FeatureCollection","totalFeatures":49,"features":[{"type":"Fe
> >> ature ","id":"states.1","geometry":{"type":"MultiPolygon"
> >> 
> >> Should this be classified as a bug or a candidate for a featere request?
> >> 
> >> -Jukka Rahkonen-
> 
> --
> Spatialys - Geospatial professional services http://www.spatialys.com

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