Tag Info

Hot answers tagged

11

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 ...


8

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.


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..


7

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 ...


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

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

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

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

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

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

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

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

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

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

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 ...


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

You cannot (to my knowledge) generate a heatmap from an unprojected layer. You will first need to reproject your source data to an appropriate projection with meter mapping units (UTM works). Right-click on your points layer, select Save As..., then next to CRS choose either Project CRS if your project has an appropriate projection, or Selected CRS to select ...


3

The term you are looking for is accessibility surface analysis/visualisation - Google will point you to many examples in the literature. One good example I found is http://www.gsd.harvard.edu/gis/manual/raster/ If you are implementing the calculation your self I'd google map algebra python and look at some of the links returned.


3

This is expected behavior. The ESRI Maps for Office help references this: Heat map layers and layers that are clustered cannot be shared to ArcGIS Online as a layer, but can be shared as part of a map. In the ArcGIS.com Map Viewer, the heat map layer displays as a point layer instead of rendering as a heat map. Source


3

I agree completely with Michael U, except that since the map without the legend already serves as a good qualitative picture and since you do already have the quantities you've derived, then you should provide a quantitative key. And definitely round the numbers to only one decimal (or even no decimals). A point that neither of you address, and I think ...


2

I'm assuming you want a density map of how "well covered" each area is, i.e. how many offices it is near, incorporating the "radius" of those offices? You can actually do all this within PostgreSQL, or at least within PostGIS, which is a free extension. I suggest you get hold of that, and read up on some of the docs. You will probably then need to geocode ...


2

The methodology you are looking for is called 'spatial statistics', and specifically 'spatial point-pattern analysis'. You could do a kernel-smoothing of the two point patterns and then compute the ratio of the kernel-smoothings. However, this is sensitive to choice of kernel shape and bandwidth, so if you wanted to draw robust statistical conclusions ...


2

Your timeit includes the numpy import, which would add some overhead. So why don't you write the code for a subset of the bounding boxes and time that loop, then multiply it up to estimate the total running time? Solving it on a single computer is by its nature serial, and with a relatively simple operation, you might not get any significant optimization ...


2

I got back an email and apparently there is an issue with the current version of the plugin, v0.2. He forwarded me the text of another email but I wanted to give the highlights incase anyone else has similar problems with the heatmap plugin. "I ran a few heatmaps myself and figured out that, there is some issue with Projection conversions. When the points ...


2

GADM as mentioned by Aaron should be your first choice as it is one of the most accurate and exact free administrative boundary shapes out there (long sentence, huu). Another great resource is the NaturalEarth dataset, which comes in various resolutions and with many more features. If for example you want to display additional geographical features (big ...



Only top voted, non community-wiki answers of a minimum length are eligible