[R-sig-Geo] Distances from points to coast do not make sense.
Agus Camacho
agus.camacho at gmail.com
Fri Sep 12 01:13:13 CEST 2014
I have two species, one is widespread in Africa (varanus niloticus) and the
other is distributed across a region of new Guinea (Varanus prasinus). I
calculated the mean distance to coast of their respective geographic
records using the following script:
x1 is a dataframe with two columns: Longitude and Latitude of geographic
records
meandist=rep(0,length(levels(x$Species)))
distance=rep(NA,dim(x1)[1])
for(n in 1:dim(x1)[1])
{
distance[n]=(dist2Line(cbind(x1[n,1],x1[n,2]),LAcl,distfun=distVincentyEllipsoid)/1000)[1]
}
meandist=mean(distance)
The problem is that geographic records from the african species is giving
me shorter distances to the coast (mean=6677) than the species from new
guinea(mean=12417). I already plotted the species records and checked there
are not bizarre records. I can send the records for anyone insterested.
Thanks in advance.
Agus
--
Agustín Camacho Guerrero.
Doutor em Zoologia.
Laboratório de Herpetologia, Departamento de Zoologia, Instituto de
Biociências, USP.
Rua do Matão, trav. 14, nº 321, Cidade Universitária,
São Paulo - SP, CEP: 05508-090, Brasil.
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