Hello,
Have you considered using the 'adehabitat' package? It presents classes
and tools for the analysis of trajectories, and automagically computes
absolute and relative angles. I'm not that familiar with polylines (in
ArcGIS or sp) so that I don't have a working example at hand, but you'd
have to extract coordinates of the polylines to build a ltraj object
(using as.ltraj), keeping the ID of the line as the ID of the ltraj, and
with 'typeII = FALSE' which means that you don't have the exact date.
In the end, an object of class ltraj is a list with a data frame for
each element of the list (for you a line), which gives you both kind of
angles among other variables (dx, dy, dist, etc.).
Hope this helps,
Mathieu.
Le 30/07/2010 03:33, Rainer M Krug a écrit :
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Hi
a friend of mine wants (needs?) to determine the angle between segments
in an ESRI polyline (line vector feature). As there does not seem to be
an easy way in ArcGIS 9.2, I thought about askeng here:
Is there way of calculating these angles between the different line
segments in R (after importing the line feature into R)?
Thanks,
Rainer
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Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
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email: [email protected]
Skype: RMkrug
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Mathieu Basille, Post-Doc
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Laboratoire d'Écologie Comportementale et de Conservation de la Faune
+ Centre d'Étude de la Forêt
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