Constraining movements in adehabitat
David, Thanks for the info and the references. I don't think I want to weight the kernel by the distance from shore since sometimes they are right on the shoreline (2 ft. of water), and they should have high UD's very close to shore. I was hoping there would be an easy way to constrain the area available, but no one has offered any. Second option is to cut out the land from the kernel distribution. Any idea if this is possible? Thanks, Tim Tim Clark Department of Zoology University of Hawaii
--- On Wed, 5/13/09, Pinaud David <pinaud at cebc.cnrs.fr> wrote:
From: Pinaud David <pinaud at cebc.cnrs.fr> Subject: Re: [R-sig-Geo] Constraining movements in adehabitat To: "Tim Clark" <mudiver1200 at yahoo.com>, R-sig-Geo at stat.math.ethz.ch Date: Wednesday, May 13, 2009, 9:18 PM Dear Tim, You can try several papers from Jason Matthioploulos, among: Matthiopoulos (2003) The use of space by animals as a function of accessibility and preference - Ecological Modelling 159 239-268 Matthiopoulos, J. 2003. Model-supervised kernel smoothing for the estimation of spatial usage. ? Oikos 102: 367?377. Unfortunately, I don't know a R implementation to do this directly. One (quick and dirty) way could be to weight the output of the Kernel estimation by a raster representing distance to coast (or ocean/continent)? Hope it helps David Tim Clark a ?crit :
Dear List, Sorry, this is a second attempt to post the same
message.? My last one got scrubbed so I changed browser options.? Hopefully this one will make it!
I am using the package adehabitat to analyze the
movement patterns and home range of the manta ray (Manta birostris) in Hawaii.? The manta rays in this study stayed close to shore, often feeding along the shore line or in small bays.? Since they can not go on land (being fish) their home range is obviously limited to the ocean area.? In calculating home range statistics, is there a way to limit the avalible area to the ocean.? I have read through the papers on Adehabitat but have not found a way to limit the area. The closest I have found is the function buffer().? Have I missed something?? Is there a way to co
nstrain the movements so that kernels will only be
computed for data points located in the ocean?
I appreciate your help and guidence. Tim Tim Clark PhD Student University of Hawaii Honolulu, HI 96816
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-- *************************************************** David PINAUD Ing?nieur de Recherche "Analyses spatiales" Centre d'Etudes Biologiques de Chiz? - CNRS UPR1934 79360 Villiers-en-Bois, France poste 485 Tel: +33 (0)5.49.09.35.58 Fax: +33 (0)5.49.09.65.26 http://www.cebc.cnrs.fr/ *************************************************** __________ Information from ESET Mail Security, version of virus signature database 4073 (20090513) __________ The message was checked by ESET Mail Security. http://www.eset.com