Hi Ricardo, if you want to get a density of school points in each polygon, you may calculate this in the field calculator. Assure, you are working in a projected coordinate sytem. Open attribute table and choose 'open field calculator'. With the field calculator dialog open, give a name to a new attribute for school density, choose an appropriate output field type (probably decimal number, real), output field length and precision and use an expression pattern like <name of attribute of points count> / $area
You get the correct syntax of your <name of attribute of points count> doubleclicking on the field's name under 'fields and values'. Be aware that $area will have the dimension of the squared coordinate reference system's measure unit (feet or meters). If you want a density based e.g. on km you have to devide your area accordingly. Regards, Christine -- View this message in context: http://osgeo-org.1560.x6.nabble.com/AREA-ATTRIBUTE-FOR-VECTOR-LAYER-tp5331699p5331704.html Sent from the QGIS - User mailing list archive at Nabble.com. _______________________________________________ Qgis-user mailing list [email protected] List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
