Caught up with the JTS team. There is a postgis function https://postgis.net/docs/ST_CollectionExtract.html that covers this concept.
There are a couple implementations in JTS, GeometryExtracter is close but only can do one geometry type at a time, and we want to do both Point and MultiPoint at the same time. The other interesting wrinkle ... - Points (Point and MultiPoint) can be extracted into a a MultiPoint - Lines (LineString and MultiLineString) can be extracted into a MultiLineString - Polygons (Polygon and MultiPolygon) ... cannot be extracted into a MultiPolygon (because they may end up overlapping) Jody -- Jody Garnett On Mon, 19 Oct 2020 at 07:29, Jody Garnett <jody.garn...@gmail.com> wrote: > This bug report is for a slightly different problem, when working with a > geometry collection the ability to filter out only the points and > multi-points. > -- > Jody Garnett > > > On Mon, 19 Oct 2020 at 02:21, Ron Lindhoudt <rlindho...@yahoo.com> wrote: > >> You should probably use the existion function `geometryType` in the SLD >> rule. >> If you don't do that a polygon is visualised as a polygon and also point >> (the centre of the polygon) for example. >> >> The only thing is that there are multiple geometry-types that represent >> Point, Polygon and Line. >> >> Polygon: >> - Polygon >> - MultiPolygon >> - MultiSurface >> - CurvePolygon >> - GeometryCollection (this is a difficult one!) >> >> Line: >> - LineString >> - CircularString >> - CompoundCurve >> -CompoundRing >> - CircularRing >> - MultiCurve >> - MultiLineString >> >> Point: >> - Point >> - Multipoint >> >> It would be nice if there was a separate function "mainGeometryType" that >> just returns Point, Polygon, Line or Collection >> >> On Monday, 19 October 2020, 10:32:15 CEST, Florian Hoedt < >> florian.ho...@thuenen.de> wrote: >> >> >> Hi, >> >> Sorry for interrupting into this conversation, but: Are you aware that >> SLD can style different geometries out of the box? See attached SLD for the >> INSPIRE theme Environmental Monitoring Facilities which does use survey >> area (Polygon) and representative point (Point) as geometry. But maybe this >> is about something different and you can ignore this. >> yours, Florian >> -- >> MSc Florian Hoedt >> Head Geoinformatics | OpenData Representative >> Thünen Institute, Centre for Information Management >> Bundesallee 44 >> 38116 Braunschweig >> >> Tel: +49 531 596-1428 >> Mobil: +49 162 92 50 275 >> Fax: +49 531 596-1499 >> Mail: florian.ho...@thuenen.de >> Web: www.thuenen.de >> >> The Johann Heinrich von Thünen Institute, Federal Research Institute for >> Rural Areas, Forestry and Fisheries – Thünen Institute in brief – consists >> of 14 specialized institutes that carry out research and provide policy >> advice in the fields of economy, ecology and technology. >> >> ------------------------------ >> *Von: *"Jody Garnett" <jody.garn...@gmail.com> >> *An: *"groznykh" <groznykh....@gmail.com> >> *CC: *"Geoserver USERS" <geoserver-users@lists.sourceforge.net> >> *Gesendet: *Montag, 19. Oktober 2020 07:05:10 >> *Betreff: *Re: [Geoserver-users] How to apply different styles for >> different geometry types in GeometryCollection? >> >> I think it is a good idea, but have not had time/budget to work on this >> myself. >> Indeed I have had this draft email replying to you open for a month or >> so. I have been very focused on transitioning our build infrastructure, >> with some small development implementing mapbox style expression support :) >> Do you have any experience with Java? Or if there are any volunteers on >> this list interested it should be a combination of: >> >> 1) https://docs.geotools.org/latest/userguide/tutorial/function.html >> >> 2) A method similar to: >> >> public <T> T evaluate(Object object, Class<T> context) { >> Expression pointExpression = parameters.get(0); >> Geometry geometry = pointExpression.evaluate(object, >> Geometry.class); >> if( geometry == null) return geometry; >> >> Expression dimensionExpression = parameters.get(1); >> Integer dimension = dimensionExpression.evaluate(object, >> Integer.class); >> >> >> switch(dimension) { >> case 0: return toPuntal(geometry); >> case 1: return toLineal(geometry); >> case 2: return toPolygonal(geometry); >> default: >> throw IllegalArgumentException("Dimension "+dimension+" >> invalid (0,1 or 2 supported)"); >> } >> } >> >> 3) And then methods to collect each type, this could probably be done a >> bit more neatly >> >> return Geometry toPuntal(Geometry geometry){ >> if( geometry instanceof Puntal) return geometry; >> if( geometry instanceof GeometryCollection){ >> GeometryCollection collection = (GeometryCollection) >> geometry; >> ArrayList<Point> points = new ArrayList<>(); >> for (int i; i<collection.getNumGeometries(); i++){ >> Geometry g = collection.getGeometryN(geometry,i); >> Geometry = toPuntal(g); >> if( g instanceof Point) >> points.add( (Point) g ); >> else if( g instanceof MultiPoint) { >> MultiPoint pts = (MultiPoint) g; >> for (int j; j<pts.getNumGeometries(); j++){ >> points.add( (Point) pts.getGeometryN(j); >> } >> } >> } >> return geometryFactory().createMultiPoint(points.toArray(new >> Point[points.size()]); >> } >> return geometryFactory().createMultiPoint(); >> } >> >> >> >> On Wed, 23 Sep 2020 at 03:51, groznykh <groznykh....@gmail.com> wrote: >> >> Hi Jody >> >> Is there a possibility that such functions would be realized? >> >> >> >> -- >> Sent from: >> http://osgeo-org.1560.x6.nabble.com/GeoServer-User-f3786390.html >> >> >> _______________________________________________ >> Geoserver-users mailing list >> >> Please make sure you read the following two resources before posting to >> this list: >> - Earning your support instead of buying it, but Ian Turton: >> http://www.ianturton.com/talks/foss4g.html#/ >> - The GeoServer user list posting guidelines: >> http://geoserver.org/comm/userlist-guidelines.html >> >> If you want to request a feature or an improvement, also see this: >> https://github.com/geoserver/geoserver/wiki/Successfully-requesting-and-integrating-new-features-and-improvements-in-GeoServer >> >> >> Geoserver-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/geoserver-users >> >> >> >> _______________________________________________ >> Geoserver-users mailing list >> >> Please make sure you read the following two resources before posting to >> this list: >> - Earning your support instead of buying it, but Ian Turton: >> http://www.ianturton.com/talks/foss4g.html#/ >> - The GeoServer user list posting guidelines: >> http://geoserver.org/comm/userlist-guidelines.html >> >> If you want to request a feature or an improvement, also see this: >> https://github.com/geoserver/geoserver/wiki/Successfully-requesting-and-integrating-new-features-and-improvements-in-GeoServer >> >> >> Geoserver-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/geoserver-users >> _______________________________________________ >> Geoserver-users mailing list >> >> Please make sure you read the following two resources before posting to >> this list: >> - Earning your support instead of buying it, but Ian Turton: >> http://www.ianturton.com/talks/foss4g.html#/ >> - The GeoServer user list posting guidelines: >> http://geoserver.org/comm/userlist-guidelines.html >> >> If you want to request a feature or an improvement, also see this: >> https://github.com/geoserver/geoserver/wiki/Successfully-requesting-and-integrating-new-features-and-improvements-in-GeoServer >> >> >> Geoserver-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/geoserver-users >> >
_______________________________________________ Geoserver-users mailing list Please make sure you read the following two resources before posting to this list: - Earning your support instead of buying it, but Ian Turton: http://www.ianturton.com/talks/foss4g.html#/ - The GeoServer user list posting guidelines: http://geoserver.org/comm/userlist-guidelines.html If you want to request a feature or an improvement, also see this: https://github.com/geoserver/geoserver/wiki/Successfully-requesting-and-integrating-new-features-and-improvements-in-GeoServer Geoserver-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geoserver-users
