Spatial clustering of points within a given line

From: Adrian.Baddeley at csiro.au <Adrian.Baddeley at csiro.au>
Subject: Spatial clustering of points within a given line
To: r-sig-geo at stat.math.ethz.ch
Cc: jutesoro at yahoo.com, Adrian.Baddeley at csiro.au, r.turner at auckland.ac.nz
Date: Monday, September 14, 2009, 3:14 PM
Julius Tesoro <jutesoro at yahoo.com>
writes:

I have a dilemma, Considering I have a number of

points and a line (shapefile). How do > I compute for the
shortest distance between a line and a point? 

In package 'spatstat' you would use 
? ? ? ? ???nncross(X,Y)
or 
? ? ? ?
???project2segment(X, Y) 
where X is a point pattern (class "ppp") and Y is a line
segment pattern (class "psp"). This computes the shortest
distance from each point to the nearest line segment,
identifies which line segment is closest to each point, and
projects each point in X to a point on the nearest line
segment. To convert your shapefile data to spatstat data,
see the vignette supplied with the spatstat package.

Also how do you identify which points aggregate near

the line 

like in spatial clustering?

I'm not sure exactly what you want to do.. You could simply
select all points whose distance to the nearest line segment
is smaller than a certain threshold. 

regards
Adrian Baddeley