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

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38
votes
3answers
9k views

Spatial clustering with PostGIS

I'm looking for spatial clustering algorithm for using it within PostGIS-enabled database for point features. I'm going to write plpgsql function that takes distance between points within the same ...
11
votes
3answers
889 views

How can I generate irregular grid containing minimum n points?

Given a large (~ 1 million) sample of unevenly distributed points - is it possible to generate irregular grid (in size, but could also be irregular in shape if that is possible?) that will contain ...
22
votes
6answers
860 views

What tools for regionalization/redistricting can you recommend?

I am looking for tools for regionalization / districting in GIS. So far I have been able to identify Districting ArcGIS extension (now also online) REDCAP (currently limited to 50k input polygons) ...
20
votes
5answers
3k views

How to identify clusters in vector point data?

I have a vector dataset of rural broadband data-points (how fast, etc.) and I'd like to explore if there are clusters of points with similar characteristics, and to plot polygons encompassing them. ...
18
votes
4answers
2k views

How to create a polyline-based “heatmap” from GPS tracks?

This winter I am planning to track my downhill skiing/snowboarding using a GPS. Most of my riding will occur at the same resort. I would like to be able to create a sort of "heatmap" that shows the ...
7
votes
5answers
2k views

Algorithm to find polygons enclosing points

I'm trying to find an algorithm that can determine the smallest possible polygons to cover a number of points. I know how to get the convex hull around all the points, but say that the points are ...
7
votes
2answers
1k views

Spatial statistics tools : clustering analysis on raster data

I've an apparently simple problem, but i can't find a clear methodology to use. I'm tasked to delimit "urban areas" by vector convex polygons, using the Gridded Population of the World dataset from ...
7
votes
6answers
5k views

How do I cluster XY point data? (ArcGIS 9.3)

I have a whole bunch of icons displaying on a map, I want these clustered together as was suggested to me for a different question here... ArcGIS 9.3. How do I increase Picture Marker Symbol ...
9
votes
4answers
4k views

How to find Clusters of N Points Within X Distance?

We have tried two methods of cluster analysis: Cluster and Outlier Hot Spot ... but neither meets our specification which has these 3 parameters: a Set of Point features N points within a ...
7
votes
1answer
179 views

Finding largest number of observations within a given radius

I have the following problem: Given the location of insured properties (say houses with fire insurance), i have to find the largest sum of insured values which fit into a 300m radius. Now, my first ...
1
vote
0answers
338 views

Cloudmade Web Maps API Marker Clustering problem

I've just started learning Cloudmade Web Maps API. I'm at marker clustering, and I'm facing a strange problem; whenever I try accessing the page below, content of elements must consist of well-formed ...
13
votes
3answers
1k views

Best practices for visualising clustered features in web maps?

I'm looking for the best symbol to display clustered features in the ArcGIS Server JS API. I don't like the "fly-out" animated cluster symbol, as used in the Silverlight API clustering or the JS ...
12
votes
4answers
3k views

Clustering Trajectories (GPS data of (x,y) points) and Mining the data

I've got 2 questions on analyzing a GPS dataset. 1) Extracting trajectories I have a huge database of recorded GPS coordinates of the form (latitude, longitude, date-time). According to date-time ...
13
votes
4answers
4k views

How to cluster spatial data in R?

I am very new to R, so please bear with me : > I have bunch of data points with latitude and longitude. I want to use R to cluster them based on their distance. I have already taken a look at this ...
8
votes
2answers
1k views

Incremental spatial clustering algorithm

I'm in search of a incremental spatial clustering algorithm. Here is my use case: users create entries with an initial position users may change the positions of existing entries I now want to ...
6
votes
1answer
859 views

Grouping map points into fixed cluster sizes

I have a dataset of 655 lat/long pairs which I'd like to split into about 100 groups. A group should have 5-10 pairs which are geographically close to each other. Dense groups should have more ...
8
votes
1answer
4k views

Using Drop Markers and MarkerClusterer together?

I want to create a rather visually appealing representation of time-series data (Costco Store Locations w/ opening dates). My idea was to plot them on a map, in time-series, but it seems that the ...
4
votes
1answer
500 views

Self organizing maps and spatially Constrained Clustering in R

There are a few algorithms to perform spatial clustering in R but most of them focus on point pattern analysis (for example here). I would like to perform spatial constrained clustering for polygon ...
2
votes
1answer
2k views

How to get Openlayers cluster strategy work for large data?

The map Layer has around 1500 points. I am able to display all the points in the map without any problem but adding the cluster strategy to the layer does not work. The Cluster strategy functions when ...
6
votes
2answers
250 views

What are my options for Server side clustering using open source GIS tools?

I need to make a webapp that will show over 40K Points on a map. These points are all across the globe. Using WFS Service and OpenLayers, it is possible to do clustering on small set of points, but ...
7
votes
2answers
435 views

How do I group near points with GPS positions?

I'm an IT person so I don't know too much about projections and so on, I hope you can help me. I have made an application for Android that collects a GPS position, so I have the latitude and the ...
7
votes
3answers
910 views

How to cluster points based on a kernel density?

I have a large dataset with 36k points representing commercial land uses, each with a field containing the square footage. I have run a kernel density analysis on this dataset, producing a raster ...
3
votes
2answers
417 views

Cluster Strategy different Labeling at Different Level

what I did? I am trying to plot some points using cluster strategy of openlayer using animatedCluster plugin. I have gson data as given: { "type": "FeatureCollection", "features": [ { ...