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Questions tagged [clustering]

Partitioning data points into subsets of objects according to their mutual "similarity," without using preexisting knowledge such as class labels.

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23 views

Rank-based Spatial Clustering in Python

I was wondering if there was any python packages out there that can do spatial clustering on ranked data? Some context: For each US state I have educational rankings. For example, for Virginia the ...
3
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0answers
33 views

Clustering based on eqaul populations

I have a map of a city that is divided into 65 sectors (building lots in purple, sector boundaries in red): In my shapefile of building lots, I have an attribute that is the total population within ...
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17 views

Merging and Clustering Rasters using QGIS?

I have 3 rasters for three regionalized variables (r1, r2, r3). The rasters have the same projection, origin and cell spacing. Can I merge this into ONE "multivariate" raster? (ie x,y,r1,r2,r3) I ...
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1answer
65 views

Removing Outliers from point layer

I am a not so newbie user of QGIS but have no knowledge of Python. I have a large dataset of points. Each point has attributes, one of which is a group it belongs to. It is expected that the points ...
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49 views

Creating Polygon from groups of points

I have a point feature class (Address Points) and I am interested in creating a polygon feature class around groups of 500 address points. Is there a way I can do this programmatically, as opposed to ...
2
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1answer
37 views

Find EPS for DBSCAN

I have location posts from Instagram Data and want to cluster them by density - using DBSCAN. I played around quite a lot with different minPts and eps but never receive clusters (always one big ...
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1answer
46 views

Identify lat long points falling out of cluster

Problem Statement I have a set of lat-long locations, say 30 in number. Ideally they should be just a few meters from each other on ground. But sometimes there's that odd junk data point that's 20kms ...
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89 views

PostGIS - Dynamic Server-Side Clustering based on Zoom level

I'm working on a Ruby on Rails application that is showing road signs on the map(leaflet). So, user can browse map and road signs, great. But, if there are a lot of signs and user wants to zoom out, ...
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91 views

Cluster points into evenly numbered groups

I need to take x number of points and equally/spatially divide them into groups. Meaning that if I had 40 points like in the image below and wanted to have 4 groups of points. Each group should have ...
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1answer
68 views

ST_ClusterDBSCAN in PostGIS gives me 0 for the cluster ID

I am trying to cluster latitudes and longitudes from a dataset containing locations in Germany (n=52612, about 9000 without duplicates). I am running the DBSCAN algorithm, but for none of the ...
1
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1answer
101 views

Performance issues with (clustered) point features

How do I get a point features layer containing roughly 2800 labeled features to perform smoothly when exported (and converted to GeoJSON) with qgis2web? Specifics: I use qgis2web 3.4.0 and QGIS 3.2.3 ...
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1answer
122 views

Clustering point data in QGIS?

Working in QGIS 3.4.1 Madeira I have a layer with many data points, for visual purposes I wish to remove some of the overlaying points. Is there a simple way to perform some sort of clustering/...
0
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1answer
69 views

Point Cluster in QGIS and Legend

I am using the point cluster symbology in QGIS and have defined the size of each point based on the cluster size using @cluster_size in the size assistant. It looks great on my map, but I cannot ...
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52 views

Cluster LineStrings using HDBSCAN?

I am trying to cluster a set of LineStrings (made out of lat/lon Points) with the help of HDBSCAN (using the "haversine" metric). The objective is to define the most "usual" path. I have only managed ...
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0answers
65 views

Algorithm to cluster coordinates within a maximum radius [closed]

I am looking for an algorithm that will allow me to find the centers of clusters of an arbitrary radius, such that all coordinates are covered. Currently, I am doing a very basic routine where I ...
3
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1answer
179 views

Server side clustering with geohash

I need help with clustering algorithm. I have a mysql database with lat, lng, geohash(12 chars). I am usign this query to select all records for zoom level 2 (2 chars) SELECT COUNT( id ) , LEFT( `...
4
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1answer
109 views

Creating Groups of points based on proximity in QGIS?

I have a dataset with around 900 points and I want to cluster them into groups of 44 based on proximity. Is this possible in QGIS? I have tried to use the convex hull tool with no success.
0
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1answer
60 views

Adding values from a table to an image band - Google Earth Engine

I'm trying to add values from a table to a cluster image. The cluster image has 50 cluster classes, and my table has 50 values for each cluster class. How do I add the values from that table to the ...
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61 views

Using output of unsupervised cluster analysis to train supervised classification for vegetation mapping?

I'm using Google Earth Engine to classify mangrove forests from Landsat imagery to calculate extent. Let's say I perform an unsupervised K-means cluster analysis on a Landsat scene to identify general ...
2
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1answer
108 views

data-defined attributes in QGIS' point cluster symbols

I'm wondering how data-defined attributes work for the cluster symbol when using the point cluster layer styling in QGIS 3.*. How can you use the values of the points within the cluster for data-...
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0answers
52 views

Data-driven cluster colour with mapboxgl

I am trying to draw circle which colour depends on a "group" attribute in my geojson. I followed a simple example with these colours: map.addSource("data", { type: "geojson", data: url, ...
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0answers
25 views

What is the best way to Clusterise Salinas dataset with highest accuracy?

I am trying to clusterize every band of a Salinas dataset (as a fair duplicate of ground truth) using kmeans and cmeans, but they are both disappointing! The spectral signatures of every available ...
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2answers
141 views

Create buffers from points by attribute

Suppose I have a points shapefile with a 'group' attribute, each value of which identifies a number of points (e.g. group=1 identifies points 1,3,6 and group=2 identifies points 2,4,5). How can I ...
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0answers
91 views

Grouped “labels” for QGIS 3.0 Point Cluster styling?

I'm trying to make a cluster visualization of a vector point layer about trees with a few requirements: The clusters need to change depending on zoom level (solved) The clusters need to indicate how ...
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0answers
55 views

cluster polygons with scipy linkage using the bounding box

I'm trying to cluster some polygons and so far I'm using linkage following this tutorial with the polygon's centroids and cutting the cluster at a specific max_distance. The results are not as ...
1
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1answer
163 views

Finding geometry of cluster from points collection using PostGIS?

I have a regular grid, each point in the grid belongs to some cluster, and I need to find geometry of this clusters. My tables look like so (only necessary fields): grid_nodes( *id uuid, ...
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1answer
64 views

Point Similarity Clustering

I am new to geographical statistics so please pardon this question if it is a duplicate. I would like to test if points that are similar are more or less likely to be near each other. I am latitude ...
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0answers
30 views

K means clustering where centroid is a node

How would you approach a k mean clustering where the calculated centroids have to be on the same position as one of the nodes? as you can see we have 2 centroids which are arguably the center of each ...
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0answers
110 views

Is Spatial clustering with PostGIS possible to generate N number of groups that have 10 elements?

I need to create a query using some sort of spatial clustering algorithm within PostGIS database. Currently, I am using pgAdmin version 4. More specifically, I need to create N number of groups that ...
0
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1answer
63 views

Filter clusters in PostGIS by size

I am clustering points in a table based on their Mercator distance (~10km, it doesn't have to be that precise, so I'm fine with projection distortion). What I want to achieve is to only query the ...
18
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1answer
512 views

QGIS 3.0 point cluster renderer, is it possible to control rendering order (z-order)?

I've been having a play with the new point cluster renderer in QGIS 3.0.2 and it's great - a lot easier (and faster) than having to do the clustering yourself. To show what I mean, here's an example ...
2
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1answer
260 views

Label display based on cluster size

In QGIS 3.0, I am using the new clustering style. I want to display labels based on cluster size. What I tried in expression field: case when @cluster_size>5 then "label_name" end
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0answers
43 views

Split shapefile to approximate area

I have a shapefile with multiple polygons of different sizes and want to split this shapefile to new ones trying to achieve a determined area, but without splitting any polygon. For example: I want ...
0
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1answer
483 views

Dynamic point clusters in QGIS

I have a point layer with singular points set with high accuracy to the position of certain sites, each point representing one site. There are 8 different types of site. When representing these points ...
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0answers
24 views

Importing xy layer with projection / Ripley's K analysis in ArcMap

I am new to ArcMap. I have a data set with a couple of thousand points. I ID'd objects in photos; each photo had a lat/lon recorded; each object was given a lat/lon based on its pixel location in the ...
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0answers
39 views

Spatial Clustering for a cluster value sum [duplicate]

I am looking to spatially cluster a series of polygons of countries The resultant groups are spatial constrained (next to one another) and need to a have a group sum greater than a certain value. ...
2
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0answers
84 views

Cluster Points on spatial network in R/QGIS

I am searching for a method for clustering spatial points along spatial lines. The points are connected to the lines. I tried nearest neighbour clustering and gProject/gInterpolate from the rgeos ...
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1answer
40 views

How to re-assign attributes based on spatial relationship

I want to re-assign the attributes of a table of regular polygons based on their spatial relantionship so that the polygons are clustered like this: This essentially means to swap the attributes from ...
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0answers
44 views

Creating polygon boundaries to group points based on common attributes using ArcGIS Desktop? [duplicate]

Does anyone know of a tool, algorithm or code that I can use to create boundaries to group points? Some groups are in defined, obvious clusters and some are mixed with lots of different coloured ...
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1answer
59 views

Dissimilarity and distance based clustering around outliers using R? [closed]

I have point data for healthcare facilities for a country - I want to first identify outlier facilities (that serve most no of patients) and then cluster nearby facilities that serve lower than ...
0
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1answer
384 views

Filter Clustering Mapbox GL JS

According to @Mourner in this gihub issue regarding filtering cluster in Mapbox here. "you'll have to filter manually and run setData to reset the whole dataset..." I have also found an example ...
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0answers
125 views

QGIS - Distance between cluster analysis not working with K means and taking to long with hierarchical method. Any advice?

QGIS- Trying to carry out a cluster analysis regarding the density of villages in Kazakhstan. I am placing latitude and longitude as my fields and not sure if this is correct (see image). ...
0
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0answers
36 views

Analyzing point feature distribution

This is a followup to Evenly assigning attributes to layer of points using ArcGIS Desktop? that was answered about evenly assigning an attribute ("A" or "B") to a collection of fixed points. If I ...
0
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1answer
406 views

How to cluster external geojson (using leaflet.ajax.js)?

Understand the method of marker clustering but unable to find the right solution for external geojson. I have tried various cluster plugins but nothing seems to work. See example map here. var ...
2
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0answers
172 views

Smoothing borders of polygons taking a layer of points into account

I'm trying to smooth borders that separate clusters of points. GRASS instrument v.generalize.smooth works pretty well, except that in some cases the points end up on the wrong side of the smoothed ...
3
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0answers
395 views

Is it possible to color the cluster base on marker color?

So far, I've been able to generate the marker color base on query from my MySQL DB. What I would like to attempt now is to cluster those markers with the dominant marker color. For example, if I ...
2
votes
1answer
590 views

Can a featureGroup be added to another featureGroup in leaflet?

I have some points that I want to be clustered in a L.MarkerClusterGroup, which works well: var cluster = new L.MarkerClusterGroup(options); features.foreach(function(feature) { var layer = L....
2
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0answers
296 views

Clustering of polygons on map using Leaflet? [closed]

There is a plugin for Leaflet to cluster the markers.The result looks like so. Result: If I like something to do to show clusters of circles and polygons? For example, when you hover over a cluster ...
2
votes
1answer
463 views

Using ST_ClusterDBSCAN on results of ST_ClusterKMeans for nested clustering with PostGIS?

I would like to pipe the results of ST_ClusterKMeans() into a ST_ClusterDBSCAN() query. The ST_ClusterKMeans gives me a fairly good results as shown in this screenshot. I classified the union of the ...
1
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1answer
87 views

Cluster points of a layer into a grid [duplicate]

I have a layer with many points on a country, for example, Peru, and I have done a grid grouping all the country. Each hole of the grid has an ID so it's easy to differentiate them. My idea is to set ...