You could probably use bucket for this. bucket puts continuous numerical values into discrete sets, so you could group together all xloc/yloc points within the same general area. Using this, if you'd want to get a count of the events within a certain range, you could do something like:
... | bucket xloc span=10 | bucket yloc span=10 | stats count by xloc,yloc
More information on the bucket command: http://docs.splunk.com/Documentation/Splunk/latest/SearchReference/Bucket
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