Hi As a simple start, you can select geometries nearby click-coordinates by doing a sql-query like
SELECT ST_AsGeoJSON(geometry_column) FROM geometry_table WHERE ST_DWithin(geometry_column, ST_SetSRID(ST_Point(<lon>, <lat>), <srid>), <srid_distance>) The geometry data will then be in a geojson string which is supported by openlayers (see http://dev.openlayers.org/docs/files/OpenLayers/Format/GeoJSON-js.html). You can read more about the functions used in the SQL-query here http://postgis.net/docs/reference.html. Feel free to ask if you have any more questions Åsmund On Tue, May 20, 2014 at 5:49 PM, dandrigo <[email protected]>wrote: > Dear all, > > I would like code a web service with python. I have already imported > several vector data (land cover) and one Digital Elevation Model > (raster layer) into my postgresql/postgis database (server side). > > I succeed in connecting to my pg db via psycopg2 (postgresql 's python api) > > Client side, operators use a client application (Developed with PHP / > javascript / openlayers). > > Objectives : Client side, once the layer would be selected,and once > the operators have clicked on the map , they would like that usefull > informations appear on the interface of the client application(kind of > land cover, z of the DEM). > > > => Regarding my python script, i have to type a SQL query in order to > select usefull informations of the db layers. And, of course, the > information must depend on geographic coordinates (Latitude > Y/Longitute X). > In a 2nd time, my script must produce a result(JSon type) for the > client side. > > > It would be possible to help me regarding the coding in order to > select usefull informations of the db layers. (depends on geographic > coordinates x/y ? Could you throw light for me regarding the way to > do this SQL query ? > > In advance, thank you to throw light for me. > > > > -- > View this message in context: > http://postgis.17.x6.nabble.com/psycopg-web-service-tp5006366.html > Sent from the PostGIS - User mailing list archive at Nabble.com. > _______________________________________________ > postgis-users mailing list > [email protected] > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >
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