[R] shapefile

Felipe Carrillo mazatlanmexico at yahoo.com
Thu Jun 24 02:18:53 CEST 2010


Hopefully the attachment will make it this time...


Hi:
I am practicing with the attached shapefile and was wondering
if I can get some help. Haven't used 'rgdal' and 'maptools' much
but it appears to be a great way bring map data into R.
Please take a look at the comments and let me know if I need to
explain better what I am trying to accomplish.

library(rgdal)
library(maptools)
library(ggplot2)
dsn="C:/Data"
wolves.map <- readOGR(dsn=dsn, layer="PNW_wolf_habitat_grid")
class(wolves.map)
dim(wolves.map)
head(wolves.map,1)
names(wolves.map)
gpclibPermit()
wolves.ds <- fortify(wolves.map)
head(wolves.ds);tail(wolves.ds)
# Shapefile of 5 states
wolves.plot <- ggplot(wolves.ds,aes(long,lat,group=group)) +
geom_polygon(colour='white',fill='lightblue')
wolves.plot
# How to show the state borders of Washington, Oregon, Idaho, Montana
and Wyoming on map?

# Subset from wolves to create a logistic regression model based on
WOLVES_99 and then apply to all the 5 states
# Remove the WOLVES_99 2(two value) and use "one" for presence and
"zero" for absence to end up with 153 records.
#wolfsub<-subset(wolves,subset=!(WOLVES_99==2))
#wolfsub <- subset(wolves.map,WOLVES_99!=2)
wolfsub <- wolves.map[!wolves.map$WOLVES_99 %in% 2,];wolfsub
dim(wolfsub)
# 42 = Forest, 51 = Shrub, > 81 = Agriculture
wolfsub$Forest<-ifelse(wolfsub$MAJOR_LC==42,1,0)
wolfsub$Shrub<-ifelse(wolfsub$MAJOR_LC==51,1,0)
wolfsub$Agriculture<-ifelse(wolfsub$MAJOR_LC>81,1,0)
names(wolfsub);dim(wolfsub)
# create the model
mod1<-glm(WOLVES_99~RD_DENSITY+Forest+Shrub
+Agriculture,family=binomial,data=wolfsub)
summary(mod1)
wolfsub$pred99<-fitted(mod1)
names(wolfsub)
#fitted(mod1)
wolfsub$pred99

# Add the wolfsub data to the map to see the map
wolfsub <- fortify(wolfsub);names(wolfsub)
area_mod <- wolves.plot + geom_polygon(data=wolfsub,aes(fill=????))
#Want to fill by WOLVES_99 but is gone #after fortify
area_mod
#Not sure how to proceed from here to fit the 'mod1' model to all
#the 5 states.

 
Felipe D. Carrillo
Supervisory Fishery Biologist
Department of the Interior
US Fish & Wildlife Service
California, USA


      
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