[OSM-talk] OT: making heat maps and overlaying on OSM data
tom at acrewoods.net
Fri Feb 27 10:55:45 GMT 2009
On Thu, 26 Feb 2009 18:19:53 -0500 (EST), simon at mungewell.org wrote:
>> Can anyone give me any tips on how to take a simple table of data with a
>> for each coordinate, and turn it into a heat map? At first I thought of
>> GeoCommons but it seems you can only use pre-processed data with their
> It sounds like you don't want to do any pre-processing... if you change
> your mind you could:
> 1). Create a coloured overlay and place that as a translucent layer.
> This could be a single image file, or another tile server (as per
> 2). Create a set of vector shapes (contours?) and overlay those using an
> OSM or other layer (could be heavy on browser if a larger area).
> The Srtm2Osm scripts already make the contours so these can probably be
> Other hint: applications like Gnuplot and matlab can take single point
> data and export a x-by-y table of data. In gnuplot use the 'set term
> table' command a replot your graph
Thanks for the tips. Maybe one day I'll look into all of that but what I'm
really hoping for is something like this:
But that allows me to use OpenLayers. I've got a simple example of the heat
map bit with OSM tiles here:
We have a table of businesses with lonlat and a CO2 emissions quantity, I
want to overlay coloured markers for each point and a heatmap layer to give
the overall impression (as with that Google-based API). I also want to be
able to produce high quality images for a printed report, i.e. not just
screenshots of a Google map if possible.
My problem is that I haven't got time to work out (in my technically
deficient way) how to turn a 2 column table into something that I can put
through gnuplot or srtm2osm and eventually get into an OpenLayers overlay.
So at the moment I'll probably have to opt for the google API.
More information about the talk