MapGlow enables displaying your geodata as heatmaps using standard WMS requests. See demo and docs at http://mapglow.opentraces.org/ .
MapGlow is a Python MapScript addition to UMN MapServer.
How it works: WMS GetMap and GetLegendGraphic requests are intercepted (using Python MapScript) for heatmap generation
from MapServer Layer Vector (Point-type) sources.
Triggered when the STYLE(S) parameter starts with the magic word "heat".
In that case the MapGlow Python script will query MapServer Layer Feature data and draw a transparent overlay heatmap. The STYLES parameter also determines the parameterization of how the heatmap should be drawn in terms of gradient colors and other parameters. See two extreme examples below:
MapGlow will delegate processing to the standard MapServer OWS dispatching
for other requests like GetCapabilities or when no STYLE(S) parameter is provided.
So the beauty of MapGlow is not just generating a heatmap, but to also function within (the confines of) the OGC WMS standard! Hence any (WMS) client can fetch heatmaps (plus control their parameterization).
Note of warning: heatmap generation is a CPU-intense algorithmic process. In production deployment therefore it is advised to use a tiling server in front like MapProxy with a MapServer-MapGlow enabled backend-WMS.
The first versions of MapGlow were developed around 2013. Starting June 2020 development is revived.