Hi Andrew,

Try also:

x1<-c(1824615,1823650,1821910)
y1<-c(5980732,5983220,5990931)
descript<-c("cat", "dog", "horse")
dat1<-data.frame(x1,y1,descript)

x2<-c(1824615,1823650)
y2<-c(5980732,5983220)
dat2<-data.frame(x2,y2)
colnames(dat2)=c('x1','y1')

merge(dat1,dat2,by=c('x1','y1'))

HTH,

Jorge


On Tue, May 6, 2008 at 5:22 PM, Andrew McFadden <Andrew.McFadden@maf.govt.nz>
wrote:

> Hi R users
>
> I am trying to create a spatial join between two datasets.
>
> The first data set is large and contains descriptive data including x
> and y co-ordinates.
>
> The second dataset is small and has been selected spatially. The only
> data contained within the second dataset is the x and y coordinates only
> i.e. no descriptive data.
>
> The aim of a join made between the two datasets is to select those
> points (and hence all the descriptive data) from dataset one that has
> the same x and y co-ordinates as dataset two.
>
> x1<-c(1824615,1823650,1821910)
> y1<-c(5980732,5983220,5990931)
> descript<-c("cat", "dog", "horse")
> dat1<-data.frame(x1,y1,descript)
>
> x2<-c(1824615,1823650)
> y2<-c(5980732,5983220)
> dat2<-data.frame(x2,y2)
>
> dat1
> dat2
>
> The aim of the join is to produce:
>
>       x1      y1 descript
> 1 1824615 5980732      cat
> 2 1823650 5983220      dog
>
> And therefore limit the data in dataset 1 to that which has the same x
> and y co-ordinates as dataset 2.
>
> Any suggestions?
>
> Regards
>
> Andy
>
>
> Andrew McFadden MVS BVSc
> Incursion Investigator
> Investigation & Diagnostic Centres - Wallaceville Biosecurity New
> Zealand Ministry of Agriculture and Forestry
>
> Phone 04 894 5600 Fax 04 894 4973 Mobile 029 894 5611 Postal address:
> Investigation and Diagnostic Centre- Wallaceville Box 40742 Ward St
> Upper Hutt
>
>
>
>
>
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