Maybe this is of use for what you want to achieve:

http://addictedtor.free.fr/graphiques/graphcode.php?graph=128

Regards,
Tim

On 16/9/2011 19:21, Greg Snow wrote:
> For adding arrows, look at the my.symbols and ms.arrows functions in the TeachingDemos package.
>
> -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain 
> Healthcare greg.snow@imail.org 801.408.8111
>> >  -----Original Message-----
>> >  From:r-sig-geo-bounces@r-project.org  [mailto:r-sig-geo-bounces@r-
>> >  project.org] On Behalf Of Jonathan Greenberg
>> >  Sent: Thursday, September 15, 2011 7:18 PM
>> >  To: r-sig-geo
>> >  Subject: [R-sig-Geo] Plotting direction vectors from an aspect map
>> >  
>> >  R-sig-geo'ers:
>> >  
>> >  Given an aspect raster (GDAL-readable), is there a way to plot the
>> >  aspect image using arrows representing each cell's direction?  I'm
>> >  assuming I have to convert the raster to a set of points -- are there
>> >  arrow symbols and, if so, can you rotate them based on some parameter?
>> >  
>> >  Thanks!
>> >  
>> >  --j
>> >  
>> >  --
>> >  Jonathan A. Greenberg, PhD
>> >  Assistant Project Scientist
>> >  Center for Spatial Technologies and Remote Sensing (CSTARS)
>> >  Department of Land, Air and Water Resources
>> >  University of California, Davis
>> >  One Shields Avenue
>> >  Davis, CA 95616
>> >  Phone: 415-763-5476
>> >  AIM: jgrn307, MSN:jgrn307@hotmail.com, Gchat: jgrn307
>> >  
>> >  _______________________________________________
>> >  R-sig-Geo mailing list
>> >  R-sig-Geo@r-project.org
>> >  https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo

-- 
#####################################
Tim Appelhans
Department of Geography
Environmental Computer Sciences
Philipps Universität Marburg
Deutschhausstraße 12
35032 Marburg (Paketpost: 35037 Marburg)
Germany

Tel +49 (0) 6421 28-25957


	[[alternative HTML version deleted]]

