New answers tagged heatmap
The value stored in a cell from a heatmap is often normalized by its area. In this case I would rather suggest an equal area projection so that you can easily aggregate to larger scale
Standard OSM tiles are in Spherical Mercator (SRID=3857) so it will probably be easiest to build your grid using the same projection. If you use SM, you might store the data at the highest zoom level OSM supports, or at the highest level zoom level you'll permit users to zoom into. If coverage is sparse, use a data structure along the lines of XIndex, ...
I think this question has been largely answered except for a couple of points about the issues. Heat maps can be great, but a classic flaw and issue lies with interpretation. Take the difference between a heat map of crime events compared to a map (heat or otherwise) of crime rate/proportion. While the event heat map might be useful in terms of identifying ...
Top 50 recent answers are included