[R] Splancs Query

emmanuel abatih adiaba1978 at hotmail.com
Mon Aug 28 10:45:53 CEST 2006

Dear R Users;
I have been using the space-time K-function analysis to detect the existence 
of clustering in both space and time. I wish to ask and know what the 
minimum number of cases should be for such analyses to be valid. I have  
data with 23 cases and don't know how careful i should be in the 
interpreting the results.

Secondly, i wish to find out if there is any bond between the results from 
the SatScan software and Splancs. In an exercise, SatScan suggested the 
presence of space-time clustering but Splancs did not present significant 
results. This might have been due to the small sample size or the way in 
which the spatial distances and times were specified for the analysis. Using 
the Burkitts data supplied with the software and changing the spatial 
distances and times for the analyses, affected the significance of the 
results.  Before or after certain spatial distances, the results were no 
more significant, also certain specifications of the times ruined the 
analyses. A follow-up question to this is if there is a paritcular techniqe 
for chosing the spatial distances and times for the analyses.

My approach of  space-time clustering is to use the space-time K-function 
analysis to check for the presence of clustering. Once present,  a search 
for their locations and tests for their significance could be carried out 
using SatScan. If not, then the plots of the spatial K-function and the 
temporal K-function could be used to drive the SatScan analysis into the 
spatial or temporal domains. Has anyone used this same approach and found it 

All help will be warmly embraced.
Thanks in advance for your help.


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