[GIS] “Disperse Markers” tool for QGIS

overlapping-featurespointqgis

I am using ArcGIS, but either I would like to use QGIS and maybe want to switch completely later.
A have a point overlapping problem, as a result of geocoding of addresses.

I have not found any tool in QGIS which could replace the "Disperse Markers" tool from ArcGIS, because if I understand well, the "Points displacement" tool in QGIS can displace the overlapping polygons only in "circle way" which has finally a very artificial effect.

Please check out these two short articles about Disperse Markers to see what I mean. Please if you know any possible solution in QGIS for this, let me know.

http://blogs.esri.com/esri/arcgis/2008/08/01/how-to-scatter-marker-symbols-for-stacked-or-clustered-point-features/

Best Answer

I think you are looking for the Point displacement renderer as illustrated in https://gis.stackexchange.com/a/57366/187

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[GIS] way to “disperse markers” across multiple point layers

I don't see any direct way, but it'd be easy enough to perform a Merge (docs) on the input data, mapping a field to retain information about the origin layer. In some cases, you may be able to use this merged layer directly, and symbolize the different features within it. Perform disperse markers on the merged set, and use as-is or split on the unique features mapped from fields.

If you only care about making them non-overlapping, and not their specific location, you could displace each layers positions by some systematic amount below the actual mapped resolution of your data, so that they were naturally clustered when mapped. For example, if you had layers A and B, you could make the least two significant figures of A something independent from B:

layer    lat     lon    rule perturbed_lat perturbed_lon
    A   33.0  -120.0  +0.033        33.033      -119.967
    B   33.0  -120.0  +0.011        33.011      -120.989

Now if you perform disperse on one of these layers, the data will already be clustered into distinct areas of the map. You'd have to play with the offset values and figure out an appropriate offset. But this approach would give you a systematic way of preventing collisions between layers.

[GIS] How to disperse points within polygons using ArcGIS

There are two potentially helpful, but old ArcScripts:

Point Randomiser v1.3

Constrain Shift by Polygon. Use a polygon theme to constrain the random movement of points. This option causes points to be randomly shifted ONLY within the confines of the polygon within which they originally fall. Users can elect to use ALL or SELECTED polygons for restraining.

Point Dispersion Wizard

The Point Dispersion Wizard disperses coincident points radially, linearly, randomly within a specified radius and randomly within a containing polygon. In addition, each dispersion pattern comes with a set of user specified options. Dispersed points can be displayed as graphics in the existing theme, clipped to a new theme, or dispersed in a new theme. It was written for ArcView 3.1 using the Dialog Designer. Be sure to study the included READ_ME.txt file as it explains the usage of the Point Dispersion Wizard, especially as it pertains to the randomly within a containing polygon dispersion pattern which behaves somewhat differently than the other dispersion patterns. The random dispersion pattern options use a prime modulus multiplicative linear congruential generator to generate random variates from the uniform distribution on the interval [0,1] based on Marse and Roberts (1983).

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[GIS] way to “disperse markers” across multiple point layers

[GIS] How to disperse points within polygons using ArcGIS

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