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51

There are at least two different kinds of heat maps: Heatmaps representing concentration of points, and Heatmaps representing distributions of attribute values Every method has advantages and problems, I'm afraid going into detail is far beyond this Q&A. I'll try to list some methods and functions for QGIS and GRASS. Concentration of points If you ...


16

While I like heat maps, I realize they are often mis-used. Typically what I've seen is a process whereby the color of each pixel is based on the result of an inverse distance weighted function applied to a collection of points. Any time a map has a lot of overlapping point markers, I think it is worth considering a heatmap. Here's a web based api. ...


15

Statistically, here is how you should go about doing a heat map: 1) Integrate point features. The idea of integration is to take points that should be considered coincident and merge them together as a single location. I like to use nearest neighbor analysis and use an appropriate value from there. (For example, when doing a crime heat map, I use the ...


12

Here is a good tutorial for doing exactly that using MapBox and TileMill: A heatmap for all your runs in RunKeeper


11

In ArcGIS, the easiest way to create a polygon layer with the count of overlapping features is as follows: Run the Union tool on your source polygon layers. This will result in a layer with one feature for each area of overlap. Add a new field to the layer created in Step 1, called NewID or something to that effect, and use Field Calculator to set it ...


9

I've done a bit of work on this in GeoTools/GeoServer by extending the Heatmap Rendering Transformation to support geometries other than points. It's not finished yet, but you can get the feature branch from my repository on GitHub. The screenshot is of GPS tracks from when I worked as a pizza delivery driver.


8

For simple heat maps and generating countour lines I've used QGis with the Grass intergration: Load data-points Load a limiting shape – eg county boundary Create a Grass mapset Open the Grass toolbox and click on the module list to search for each tool Load v.in.ogr.qgis module and load both the point data and the boundary shape, each time remembering to ...


8

A good article from ESRI called "Extending your map with spatial analysis" explains and give examples of both. Another good article, "Heat Maps in GIS", found over on GIS Lounge, shows that these terms can sometimes be used interchangeably. I think the first paragraph of the article gives a great explanation of the term(s): Heat mapping, from a ...


7

Maybe these links will help you: How to build effective heat-maps? with QGIS: http://alexsciuto.com/blog/2010/11/how-to-make-your-own-heat-map-pt-1-gathering-the-materials/ Python script: http://www.sethoscope.net/heatmap/ http://sk53-osm.blogspot.com/2011/01/heat-maps-from-osm-pois.html Sorry for a non elaborated answer..


6

Use the Heatmap plugin. It is the icon with two yellow circles. You can get to it by either right-clicking somewhere on your toolbar and select from the popup menu of plugins or you can go to Plugins -> Manage Plugins.


6

Yes, the Heatmap plugin can be used for this. Suppose we have a point layer called pointrates.shp with rates between 0 and 1 associated with each point: We can run the Heatmap plugin on this, using a Decay Ratio of 1 (which means that the value at the edge of each search radius is the same as at the center), and using the "Ratio" column as the Weight. In ...


5

If I understand your question correctly I have done something similar before; just had to remember what I did. This will work if your polys are overlapping AND not the same layer. If they are on the same layer and it it is possible, move them to seperate layers, if you don't the target layer will just inherit one of the values. The key process to use is ...


5

A kernel density for this size grid only takes a fraction of a second. Evidently, the problem is that v.kernel is processing every one of your three quarters of a million points with too much precision and detail. Instead, first create a grid to represent the point data, possibly using a finer resolution to reduce the discretization error in location. ...


5

One of the best sources of administrative boundaries is Global Administrative Areas. I downloaded the Russian administrative boundaries and there are four shapefiles included with the zipped file of varying levels of administrative boundary detail. The attached image shows Russian administrative level 1 boundaries, which include autonomous provinces, ...


5

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.


5

On using the heatmap plugin This discussion should shed some light on how this plugin works: the procedure in which pixel values are computed is explained in the Context Help. Its just a linear assignment, say for a buffer of 10 pixels, and decay of 0, the central pixel has a value of 1, 2nd from center pixel has 0.9 and so n upto the 10th pixel with ...


4

The HEATMAP plugin is available in Plugins -> Manage plug-ins option in Quantum GIS 1.8 version. You select it and press add. It will then appear as an option in Raster -> Heatmap command line.


4

From what I can see in the pictures you posted, there is not much variation in the heatmap raster. Try decreasing the radius value to better preserve local variations. Update: Without seeing your settings, I can only guess that you set the radius to a value smaller than the cell size. That will obviously cause problems. Decrease the cell size but note ...


4

I was generating similar graphs due to some confusion over the CRS. Basically, you need to make sure that both your project and your vector layer are using the right CRS. I was able to fix this problem by doing the following: Open the Project Properties menu and select "Enable 'on the fly' CRS transformation". Select "WGS 84 / World Mercator" as the CRS. ...


4

Maybe you can generate a set of random points into your polygons, there is a QGIS tool for that ? If you have overlapping polygons, then you have higher density of them in this area. Then use heatmap for the points. You would need to run several rounds to find optimal number of points, as result depends on that. If your data shows distribution of some ...


4

Coincidentally, I have been doing a lot of reading about this subject over the last couple of days. For the actual generation of heat maps there are a large number of factors to consider. The most valuable resources for me were from Laura Rosenshein at Esri. She sums up a lot of the material in this one blog post. To answer your question, I would ...


4

It might also be worth checking out this library which is hosted on the new ESRI github. The library allows you to make a heat map on the client side using HTML5. A demo of the application: http://esri.github.io/heatmap-layer-js/ The github site: https://github.com/Esri/heatmap-layer-js


4

Try making a heatmap for each separate category. Then sum the heatmaps and normalize them using number of categories. This might be worth exploring.


4

The values in the attribute table are not the coordinates of the geometry. You can create attribute field data from the geometry, but it does not work the other way round. If you change the values, you do not change the geometry; and if you move points manually, the values in the attribute table are not changed automatically. You have to re-import the data ...


3

So need the shapefile the administrative regions of Russia? If you have the data you can add both the and the table to the project. Your table needs to be in a format that qgis can read, like dbf or csv. If each field in your excel file has a unique value you can join those with the shape by right clicking on the layer properties > Joins. for the data: ...


3

I suppose you have the current standard version Wroclaw 1.74 Please read this post by underdark (in the comments) http://underdark.wordpress.com/2012/03/04/mapping-density-with-hexagonal-grids/ she writes: "Yes, if you have current QGIS Trunk installed, you can activate a “Heatmap” plugin. It will show up in Raster menu."


3

Try this instead, if it fits your requirements, it isn't a computational solution to the dataset but if you are looking for simply an infographic solution you could try this instead. Join attributes by location, with your heaxgonal cells as as the target and your point data as the join. Choose to keep all features. Set the symbology to the cells with the ...


3

I suggest you use the GRASS plugin -- QGIS has pretty limited functionality (and why reinvent the wheel in python when software like GRASS already exists?): v.in.ogr.qgis [next two lines might be necessary, depending on whether your polygons already have a value] v.db.addcol v.db.update_const this is where we add up the overlap in the polygons then ...



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