AI-GEOSTATS: Ripley's K

[Mathias Tobler]

I am using Ripley's K to analize distribution patterns of trees in a forest plot. Here some basic information. The plot is 1000 x 1000 m. There are 7765 trees that were measured throughout the plot. This is the first time I am unsing Ripley's K and I run into several questions / problems.

I am using Crime Stat 2.0 and SPP (by Peter Haase) to calculate the statistcs but get very different results from the two packages. Both packages are supposed to output SQR(K(t) / Pi) - t for the data set and the confidence intervalls. The following link shows the output from both packages.

http://www.botanypages.org/Mathias/ripleysk.jpg

Both were run with 19 iterations and Rectangular Bordercorrection was used in Crime Stat. The third graph shows the Coefficient of Dispersion CD=SD^2/M for diffferent quadrant sizes.

Does anyone have an idea what the problem could be? Why do the confidence intervals show a curved shape and are not around 0? Is there any other free and easy to use software to calculate Ripley's K (I know that there is R but I don't have the time right now to get familiar with it).

Thanks for your help,

Mathias


--
* To post a message to the list, send it to [EMAIL PROTECTED]
* As a general service to the users, please remember to post a summary of any useful responses to your questions.
* To unsubscribe, send an email to [EMAIL PROTECTED] with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list
* Support to the list is provided at http://www.ai-geostats.org