Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

I have a point pattern (see below) in which I assume to find "significant" lines of points. However, I did not find any method that is integrated in a GIS or in R that searches for such line pattern in a spatial point pattern. There is one method that is implemented in the free software called PAST (http://folk.uio.no/ohammer/past) called point alignment.

the method is described in :

Hammer, Ø. (2009). New statistical methods for detecting point alignments. Computers & Geosciences, 35(3), 659-666.

beyond this method I am not aware of any tool that finds lines in point patterns. Any hints on possible tools, r-packages, etc. are most welcome.

Spatial pattern of individual plants

share|improve this question
    
can you expand on what you consider to be significant? just colinear? –  iant Sep 3 '13 at 8:44
    
good question. I am not sure how to describe "significant" here. "colinear" is a good word though. I mean I "see" many lines but are these points really lined up or not? and if so, how many lines are there? as Oyvind stated below, it depends on the search radius. –  Jens Sep 3 '13 at 17:55

2 Answers 2

This paper: Christophe & Ruas 2002, Detecting Building Alignments for Generalisation Purposes, ISPRS, Ottawa. describes an operational method for the detection of small surfaces (buildings) alignements - it should work even better with points! (this method is rather robust since it is used for the production of 1:25000 maps in France).

share|improve this answer
    
dear julien, great I will try to implement this approach in a r-function. look's interesting. –  Jens Sep 3 '13 at 17:37

I'm the author of Past and that paper you refer to. From your plot it seems like you have used a too large search radius. Try to decrease the Radius value. Also, if you would like to detect more lines, increase the alpha value (significance level).

share|improve this answer
    
Oh, wow, that´s a surprise. :) In the plot I just draw a line by hand in order to make my message more clear. increasing alpha indeed gives more lines and I found many patterns. however, when do I know that I found the optimal solution? and should alpha be more like 0,05 or 0,1? one more problem is that lines appear/disappear when switching the radius from small to large. should I just notify all significant lines at all radii? one last question: what´s next after lines are identified? display them in a GIS? thanks for your comment and PAST ! –  Jens Sep 3 '13 at 17:39

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.