sld density heatmap with geoserver without weight atribute

Question

I try to generate a density heatmap to display my points density but I don't know what to write in the weightAttr area of the tamplate furnished in the doc because I just have plenty of points but they don't have weight attribute.

I can generate it with QGIS but the sld export isn't available for heatmap.

I can also generate it using openlayers from geojson file but I have more than 1.000.000 points and it crashes.

I think it's better to use postgis and geoserver to generate wms to display so many points.

Answer 1

I found a way to display my heatmap without any lag!

1) Copy the project (index.html) in a new folder in geoserver directory to allow web browser to catch wfs from geoserver (if you dont do that you'll have a 'cross origin' error message in the console).

ex: /usr/share/geoserver/webapps/map/indexhtml

2) I used geojson wfs of geoserver in openlayers

var heatmap = new ol.layer.Heatmap({
        source: new ol.source.Vector({
             projection : 'EPSG:4326',
             url: 'http://localhost:8080/geoserver/robot/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=YOUR_WORKSPACE:YOUR_LAYER&maxFeatures=NUMBER OF FEATURE YOU WANT TO LOAD&outputFormat=application%2Fjson',
             format: new ol.format.GeoJSON()
          }),
                         opacity: 0.6,
                 radius: 15,
             });

It works but I'm not sure of the reliability of the heatmap because I don't know how geoserver selects points.