[R] R matching lat/lon pairs from two datasets?

[Douglas M. Hultstrand]

Hello,

I am trying to match lat/lon from one dataset with the lat/lon from a 
second dataset and use that rows data for calculations.  I am using 
match, but this is finding the first match and not comparing the pair, 
how can I determine if the lat/lon are the same?  See example below.  Is 
there a better way to determine to a matching pair of lat/lon values?

Example Datasets:
 > data2
       V1    V2 V3
1 -123.76 47.82  8
2 -123.75 47.82 11

 > data[1:2]
      V1      V2
1  47.82 -123.76
2  47.82 -123.75
3  47.82 -123.74
4  47.82 -123.73

#Subset of current R code :
lat <- data$V1
lon <- data$V2
yrs <- c(1,2,5,10,25,50,100,200,500,1000)
lon2 <- data2$V1
lat2 <- data2$V2
ppt2 <- data2$V3

for(i in 1:length(lat2)) {
        loc <- match(lat2[i],lat)
        loc2 <- match(lon2[i], lon)
        print(loc); print(loc2)

        #Need to test to make sure loc equals loc2
        freq_ppt <- 
c(data[i,4],data[i,6],data[i,8],data[i,10],data[i,12],data[i,14],data[i,16],data[i,18],data[i,20],data[i,22])
        print(freq_ppt)
        return_value <- approx(freq_ppt,yrs,xout=data2[i,3])
        print(return_value)
}


Thanks for your help,
Doug

-- 
---------------------------------
Douglas M. Hultstrand, MS
Senior Hydrometeorologist
Metstat, Inc. Windsor, Colorado
voice: 970.686.1253
email: dmhultst at metstat.com
web: http://www.metstat.com