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GIS Cluster Analysis

Posted on 2011-10-03
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Hello Exchangeperts,

I was asked to write a function that identifies a cluster of latitude and longitude points from GPS tracks of animals.  Each point has a date/time stamp and LAT.LON.  The point is to identify a den, shelters, birthing ground, or anywhere the creature has hung out for some time relative to time in motion, or even the time the tracker was in place.  I started looking into 'cluster analysis' and found a couple dozen techniques/algorithms.  I'm wondering if anyone has done something like this and can point me to code examples.  Are there required inputs from the user like distance of possible cluster points to other points, percentage of candidate cluster points vs. overall number, proximity and time components.  Is there any normally accepted criteria for what constitutes a cluster vs. the general data and how is that figured.  When I looked at the data points on a GIS program it was like porn, I knew one when I saw one; but how do I do it programmatically?

I'd be using VB.net

Thanks for your thoughts  
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Question by:zipnotic
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zipnotic earned 0 total points
ID: 36934278
So, I'm feeling a bit neglected on this question but here is what I am thinking:

1. Order data points by date/time stamp
2. calculate distance between each point
3. Throw out distances where datetime is greater than average (it means the tracker couldn't find a gps signal)
4. Include both points that are certain distance from each other (supplied by user) but only when there are more than 4 points (or any other number supplied by user)
 
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by:zipnotic
ID: 36963487
Anyone have good coded example of a Nearest Neighbor algorithm in vb or c#?
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Expert Comment

by:ddurgaprasad
ID: 36963568
Read the below mentioned article for an introduction on clustering applications.
http://www.tonygrubesic.net/hot_spot.pdf

ESRI ArcGIS has relevant material at  http://webhelp.esri.com/arcgisdesktop/9.2/index.cfm?TopicName=Modeling%20spatial%20relationships

ESRI ArcGIS has tools that carry out spatial clustering.The tool has an COM API called ArcObjects,which you can use to hook up with  VB or c# NET application.

If wish to write the things from scratch ,this article may help you http://www.nku.edu/~longa/geomed/ppa/doc/html/ppa.html
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Author Comment

by:zipnotic
ID: 36964893
ddurgaprasad: Thanks for your response.
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Author Closing Comment

by:zipnotic
ID: 37052292
I was hoping for some coded examples rather than research related to the issue.  I was able to find some code on another website and modify that to suit my needs.
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