Use the "bubble" command in gstat.
-Roy M.
On Jan 9, 2009, at 5:58 PM, t c wrote:
> Dear R help list,
>
> I am working on some data from a study on the habitat use and
> movement patterns of fish using a marine protected area in Hawaii.
> We have a number of acoustic receivers in a MPA, and any time a
> tagged fish passes within range it records the date and time of
> detection. I am trying to make bubble plots showing the number of
> detections for each fish at each receiver. I have been able to get
> it to work using a map generated from GSHHS data (Global Self-
> consistent, Hierarchical, Highresolution Shoreline) but the map data
> is not of high enough resolution. Instead I am trying to plot the
> data on a shapefile, but I can't find out how to project the
> shapefile correctly to match up with the data. I know my shapefile
> is in NAD 1983 UTM Zone 4N and my data is in WSG84. How do I change
> the projections to make them line up? I tried mapproj but couldn't
> get it to work. Any suggestions would be greatly appreciated.
>
> My code is below. I have also attached the shapefile and my data.
>
> Thanks in advance for your help.
>
> Aloha,
>
> Tim
>
>
>
>
> #Read ESRI shapefiles
> library(maptools)
> library (PBSmapping)
> setwd("E:/Telemetry_research/Kealakekua Bay MPA study/R bubble
plot")
> hawaii.coast<- read.shape("coast_n83.shp")
>
> #Read data and convert to event data
> mydat<-read.table("my.event", header=TRUE)
> my.event<-as.EventData(mydat,projection="LL")
>
> #Calculate bubble size
> detects<-mydat$Detections
> max.symbol.size=10
> min.symbol.size=1
> bubble.size <- (detects-min(detects))/((max(detects)+.0001)-
> min(detects))*(max.symbol.size-min.symbol.size)+min.symbol.size
> #Calculates bubble size as a range between min and max. 0.0001
> added to avoid division by zero if only one sample.
>
> #Plot of all Hawaiii showing point data somewhere to the south.
> Needs projcting?
>
plot(hawaii.coast,xlab="Longitude",ylab="Latitude",main="Kealakekua
> Bay")
> addPoints(my.event, pch=19 ,col="red",cex=500)
>
>
>
> #Plot of location where point data should be
> plot(hawaii.coast,xlim=c(820000, 824000), ylim=c(2154000,
>
2158000),xlab="Longitude",ylab="Latitude",main="Kealakekua
Bay")
>
>
>
> <
>
my.event><coast_n83.prj>______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
**********************
"The contents of this message do not reflect any position of the U.S.
Government or NOAA."
**********************
Roy Mendelssohn
Supervisory Operations Research Analyst
NOAA/NMFS
Environmental Research Division
Southwest Fisheries Science Center
1352 Lighthouse Avenue
Pacific Grove, CA 93950-2097
e-mail: Roy.Mendelssohn at noaa.gov (Note new e-mail address)
voice: (831)-648-9029
fax: (831)-648-8440
www: http://www.pfeg.noaa.gov/
"Old age and treachery will overcome youth and skill."
"From those who have been given much, much will be expected"