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setwd("~/acrobates/adamw/projects/interp/data")
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library(reshape)
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library(sp);library(rgdal);
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library(reshape)
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library(ncdf4)
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library(geosphere)
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library(rgeos)
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library(multicore);library(RSQLite)
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stInfo=function(file,inventory,vars=vars){
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  ### read in station location data
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    cs=c(11,-1,8,-1,9,-1,6,-4,30,-1,3,-1,3,-1,5) #column widths, negative means skip
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      print("Importing station data")
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      st=read.fwf(file,widths=cs,colClasses="character",comment.char = "",header=F,skip=0)
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      colnames(st)=c("id","lat","lon","elev","name","gsnflag","hcnflag","wmoid")
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      print("Updating factors")
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      for(i in c(5,6,7,8)) st[,i]=as.factor(st[,i])
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      for(i in 2:4) st[,i]=as.numeric(st[,i])
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    ### inventory
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      print("Getting station start-stop years from station inventory file")
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      cs=c(11,-1,8,-1,9,-1,4,-1,4,-1,4) #column widths, negative means skip
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      stinv=read.fwf(inventory,widths=cs,colClasses="character",comment.char = "",header=F,skip=0)
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      colnames(stinv)=c("id","lat","lon","variable","yearstart","yearstop")
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      stinv=stinv[stinv$variable%in%vars,]
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    ### reshape yearstart
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      stinvw1=cast(stinv,id+lat+lon~variable,value="yearstart")
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      colnames(stinvw1)[!grepl("id|lat|lon",colnames(stinvw1))]=
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            paste(colnames(stinvw1)[!grepl("id|lat|lon",colnames(stinvw1))],".start",sep="")
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    ### reshape yearstop
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      stinvw2=cast(stinv,id+lat+lon~variable,value="yearstop")
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      colnames(stinvw2)[!grepl("id|lat|lon",colnames(stinvw2))]=
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            paste(colnames(stinvw2)[!grepl("id|lat|lon",colnames(stinvw2))],".stop",sep="")
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      stinvw=merge(stinvw1,stinvw2)
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      for(i in colnames(stinvw[,!grepl("id|lat|lon",colnames(stinvw))])) stinvw[,i]=as.numeric(as.character( stinvw[,i]))
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      colnames(stinvw)=sub("TMAX","tmax",colnames(stinvw))
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      colnames(stinvw)=sub("TMIN","tmin",colnames(stinvw))
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      colnames(stinvw)=sub("PRCP","ppt",colnames(stinvw))
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    ### merge the data
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      print("Merging start-stop dates with station locations")
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      st2=merge(st,stinvw[,!grepl("lat|lon",colnames(stinvw))],all.x=T,by=c("id"))
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    ## add station type field
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    st2$type=ifelse((!is.na(st2$tmax.start)|!is.na(st2$tmin.start))&!is.na(st2$ppt.start),"T&P",
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      ifelse((!is.na(st2$tmax.start)|!is.na(st2$tmin.start))&is.na(st2$ppt.start),"T",
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             ifelse((is.na(st2$tmax.start)|is.na(st2$tmin.start))&!is.na(st2$ppt.start),"P","None")))
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    ### Convert to spatial points and return
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      print("Convert to spatial points")
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      coordinates(st2)=c("lon","lat")
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      st2@data[,c("lon","lat")]=coordinates(st2)
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      proj4string(st2)=CRS("+proj=longlat +datum=WGS84")
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      return(st2)
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  }
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### Process the station data
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st=stInfo(file="ghcn/ghcnd-stations.txt",inventory="ghcn/ghcnd-inventory.txt",
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    vars=c("PRCP","TMAX","TMIN"))
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writeOGR(st,".","stationlocations",driver="ESRI Shapefile",overwrite=T)
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