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10 votes

Doing heatmap from line data in QGIS?

Since QGIS 3.12 there is an algorithm called Line Density listed in the interpolation algorithm group in the Processing Toolbox (accessible via Processing -> Toolbox). It is a direct port of the ...
DMAD Tim's user avatar
  • 211
7 votes

Doing heatmap from line data in QGIS?

I can't find a way to do this in QGIS via the DB Manager / SQLite functions, but in PostGIS, we do the following: select (ST_DumpPoints(l.geom)).geom from linedata as l This, exported to a new table,...
DPSSpatial_BoycottingGISSE's user avatar
7 votes

Doing heatmap from line data in QGIS?

Using a similar approach to the answer from @DPSSpatial, I would use the QChainage plugin to create evenly spaced points along each line. This plugin generates points along the line, but it doesn't ...
Steven Kay's user avatar
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7 votes

Doing heatmap from line data in QGIS?

In fact, it is possible to do line density in QGIS using the standard menus sending parameters to the GDAL executables. Using gdal_rasterize using the -burn -add switch would create a raster of ...
Karl Zinglersen's user avatar
7 votes
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What does "layer units" mean?

The documentation says Radius: Is used to specify the heatmap search radius (or kernel bandwidth) in meters or map units. The radius specifies the distance around a point at which the influence ...
JGH's user avatar
  • 42.1k
7 votes

Uncertainty of a line between two coordinates with uncertainties in QGIS

That was a fun problem! I solved it using QGIS 2.18 but I don't think the tools have drastically changed in 3.0. 1. Generate the lines I won't give much details here since you already have the lines ...
ArMoraer's user avatar
  • 5,639
7 votes

Population density: 1000 people/ km2

Population density is simply calculated by: Number of People / Land Area Therefore, 1000 people/km2 is the population density in your case. Often, population density is measured in km^2 or mi^2 as ...
Aaron's user avatar
  • 51.7k
6 votes

Calculating Line Density in QGIS?

Since the release of QGIS 3.12 you can use the native Line Density algorithm from the processing toolbox. It is implemented in C++ and is a 1:1 port of the Line Density tool that is available in the ...
root676's user avatar
  • 2,385
6 votes
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Build Density Map for large dataset

I did a bit of testing and came up with the following solution based on this blog post from Vipin Raj. I think this is the best answer until now, as everything is done on the postgis server. CREATE ...
pgross's user avatar
  • 493
5 votes

Creating population dot density map at the block group level in QGIS

Use Vector -> Research Tools -> Random Points Inside Polygons. Select the variable, which contains the number of people in each Block (=polygon) under expression. leave sampling strategy ...
Kurt's user avatar
  • 7,097
5 votes
Accepted

QGIS town label density

I'd be curious to see the data you got, in which you claim there are not fields useful for filtering out smaller localities. QuickOSM will pull in the place and population tags for populated places. ...
jcarlson's user avatar
  • 3,900
4 votes
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Calculating density map of cycleways using fishnet in ArcGIS Desktop?

To do this I would: Intersect your cycleways and the fishnet Use Summary Statistics to SUM the lengths of the intersected cycleways by fishnet polygon ID Use Join Field to join the summed lengths ...
PolyGeo's user avatar
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4 votes
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Centroids highest density areas

First you need to convert your Raster to Polygon. Then You can use Eliminate and\or minimum bounding geometry to clean up your polygons. Select your red polygons in any way you wish and run Feature to ...
Dmitriy Litvinov's user avatar
4 votes
Accepted

Creating population dot density map at the block group level in QGIS

Unfortunately, you can't set dot density style in QGIS (for now, I hope) as easily as you can do in ArcGIS. You can do it by creating a new Point layer. Do not expect any hope from style window. You ...
Kadir Şahbaz's user avatar
4 votes

Producing density map in QGIS

You want the "Graduated" symbology option. Just choose the column the has the values and choose 4 classes.
HeikkiVesanto's user avatar
4 votes

Choosing kernel density radius

These are complicated questions, and yes, it does depend on your data but also on your hypothesis. For example you may have an explicit hypothesis regarding boat activity, requiring a set of sigma (...
Jeffrey Evans's user avatar
4 votes

Heat Map - Cover non-point areas QGIS

Use the Heatmap renderer for your point-layer: it will cover the whole map canvas. If you want to cover everything outside of a certain polygon area (city), render this polygon with Inverted Polygon ...
Babel's user avatar
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4 votes
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Create density map with grid

From this point it is not clear what you would like to have as map in the end. If you need a vector file, do the following in QGIS: search for "create grid" in the toolbox and create the ...
HeyGeorge's user avatar
  • 138
4 votes

Calculating point density as attribute in point layer in QGIS

The best one-step method I can think of is using the Field Calculator to directly create a new attribute with this expression: array_length( overlay_nearest( @layer, $id, ...
Babel's user avatar
  • 71.5k
4 votes

Calculating point density as attribute in point layer in QGIS

There is a possibility of using a "Virtual Layer" through Layer > Add Layer > Add/Edit Virtual Layer.... Let's assume there is a point layer called 'points_in_polygon', see the image ...
Taras's user avatar
  • 33k
4 votes
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Find location of highest point density in QGIS?

Heatmap. Set a search radius, output raster size and kernel_shape=Uniform (Advanced options) Raster pixels to points to create a point in each raster cell center with the column VALUE storing the cell ...
BERA's user avatar
  • 73.8k
3 votes
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How to create a population density heatmap from attributes

In QGIS, you may try to follow these steps: Right-click on the layer loaded in the Layers Panel; Go to Properties >> Style; Choose Heatmap; Define the field to use for the heatmap (and the ...
mgri's user avatar
  • 16.2k
3 votes

Getting quantity of intersecting lines of polygons in QGIS?

I tried to also use the refFunctions, in particular the intersecting_geom_count function but I think this only applies if the geometry from both the target and the source are the same. But we can ...
Joseph's user avatar
  • 75.9k
3 votes
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Calculate Density in QGIS

Your approach have some problems. Creating a grid for calculating density could be wrong, because the dimension (and position) of the grid changes the density (if a group o buildings falls inside two ...
Sergio's user avatar
  • 1,097
3 votes

Identifying true curves/arcs in ArcMap?

Building on @KHibma's answer, the data access cursor has the token SHAPE@JSON which can be used to check for curves without importing the json module. with arcpy.da.SearchCursor ("InputFeatures", ["...
Emil Brundage's user avatar
3 votes
Accepted

Estimating population in flood zones?

Population is an estimate, as it stands, so I'm assuming you are looking for a 'best-guess' type of workflow that will give the best results for the littlest amount of time spent. ArcGIS's Tabulate ...
MaryBeth's user avatar
  • 3,714
3 votes

How to reduce points by proximity

In the top toolbar: Vector > Shape Tools > Geodesic Geometry Simplification > Geodesic point decimate. You can then specify the input layer, specify the minimum distance between points, and ...
TMK's user avatar
  • 51
3 votes

Density map of pedestrian paths and footways in QGIS

Here my workaround: 1) Create an intersect of your lines layer (path/footways) and your polygon layer (grid or areas, e.g. neighborhoods) where you want to represent the density. Your polygons, areas,...
Ruben FV's user avatar
  • 346
3 votes

Population density: 1000 people/ km2

They calculate the population density by dividing the number of people by the area of land in square kilometer. If you want to get in people/m2, then you have to divide the result by 1.000.000. 1.000 ...
Kadir Şahbaz's user avatar
3 votes

Line density for multiple commuters in QGIS

You could try to create a 10m Buffer around your line segments. With the respective geometry operation you should be able to then give the buffer a value according to how many lines overlap with the ...
Chris P's user avatar
  • 1,639

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