Tagged Questions

Assembling nearby data points into groups

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10
votes
3answers
507 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 ...
30
votes
3answers
5k 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 ...
22
votes
6answers
701 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) ...
6
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 ...
6
votes
6answers
4k 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 ...
1
vote
0answers
213 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
829 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 ...
10
votes
4answers
2k 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 ...
8
votes
2answers
992 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
5answers
1k 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 ...
6
votes
1answer
486 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
3k 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 ...
2
votes
1answer
672 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 ...
7
votes
4answers
3k views

Find Clustered Points Within X Distance with N Points

We're planning on doing some cluster analysis exposed as a geoprocessing service in ArcGIS 10 - specifically these two: Cluster and Outlier Hot Spot But we have to meet a specification for cluster ...
5
votes
2answers
150 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
3answers
713 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 ...
6
votes
1answer
152 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 ...