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There was already a question about it in 2010, where the answer was basically "use QGIS Heatmap plugin".

I've also read on QGIS webpage that it is now "implemented as a native C++ plugin"

My question is probably stupid, but I haven't found the answer: what is the best way to generate a heatmap from a list of observations, in QGIS?

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Why can't you use the heatmap plugin? This is what it's for. –  Nathan W Mar 20 '12 at 22:38
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Is the list of observations in something like a shapefile, or is it in a non-spatial format such as a CSV file? –  Simbamangu Mar 21 '12 at 4:23
    
It's a CSV file. And about the heatmap plugin, Nathan, that's precisely my question: how to use it? –  Antonin Mar 21 '12 at 8:46
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Take a look at this excellent tutorial at qgis.spatialthoughts.com/2012/07/… –  RyanDalton Dec 1 '12 at 1:44

2 Answers 2

up vote 5 down vote accepted

I've just learned that the heatmap plugin is not part of version 1.7, so if that's what you're using (like I am), it's not here for us to use it yet. If you're using the "trunk" version of QGIS the heatmap can be found under the Raster menu.

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I'm going to try right now. Thanks a lot. –  Antonin Mar 23 '12 at 14:42
    
(and I just notice now it was written in the 2010 question: "QGIS Heatmap plugin (available in versions > 1.7.x)", strict >) –  Antonin Mar 23 '12 at 14:59
    
Thank you Diana, and welcome to our site! –  whuber Mar 23 '12 at 17:05
    
I installed QGIS 1.9, and there is a heatmap pluging. I imported 186 points in my map (delimited text layer), and from these points I'm trying to create my heatmap with the plugin. Unfortunately, I only get a grey rectangle. I'm working on a space of order of magnitude of 0.005 degrees, with a buffer radius of 10 and a decay ratio of 0.5. Does anyone have an idea how I should use the plugin? –  Antonin Mar 25 '12 at 20:34
    
Hi Antonin. I'm not able to help you with the plugin itself since I can't use it with my Windows 1.7 version yet. But I'm questioning your spatial coordinates themselves. Heat maps (i.e., density maps) should be generated with points that have been projected, away from degrees (spherical coordinates). You'll want to have a regular, Cartesian surface (and probably end up with units in meters or km for your buffers and ratios). Can you project the data first to whatever might be a suitable projection for your AOI? –  dianamaps Mar 25 '12 at 22:01

Go to the properties for the grey rectangle and change to pseudocolor.

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