This library contains a Leaflet layer that renders a Solr heatmap.
The library can be installed via bower:
% bower install leaflet-solr-heatmap
Once installed simply include heatmap.js after the leaflet scripts:
<script src="bower_components/leaflet/dist/leaflet.js"></script>
<script src="bower_components/leaflet-solr-heatmap/dist/heatmap.js"></script>
And finally add it to the map.
L.SolrHeatmapLayer('http://localhost:8983/solr/<core>', {
field: 'geo'
}).addTo(map);
See the a working example.
SolrHeatmapLayer takes a number of configuration options:
| Name | Default | Description |
|---|---|---|
| field | geo |
The Solr spatial field. Currently this must be an RPT field. |
| query | {q: '*:*'} |
Object defining Solr query (q, fq, etc...). |
| colors | ['ffff00', 'ff0000'] |
Two colors for the low and high intensity areas of the heatmap respectively. Specified as 6 digit hex values. |
| blur | 5 |
The radius in pixels of the blur filter to apply during heatmap rendering. |
| opacity | 0.5 |
The opacity of the heatmap layer. |
| interp | lin |
Interpolation method used to generate colors from intensity values. One of lin (linear), log (logarithmic), or exp (exponential). |
Heatmap Faceting is documented in the Solr spatial docs.
The heatmap layer works by rendering the heatmap data directly using the browser canvas api. This is a much more efficient approach than creating objects and adding them to a leaflet vector layer. The canvas layer infrastructure is provided by a plugin from CartoDB.