When I make a sample in sp, for example a random samping of 5 points in dataset1: sample.dataset1=spsample(dataset1, n = 5, "random") I have a sp object for the selected sampling... My question is : How can I extract from dataset2 the points & data for the coordinates(sample.dataset1) ? The dataset2 would be an object with the same area and coordinate system, but I would like to extract for the coordinates of sample.dataset1 the data in each point for dataset2. I didn't found a way to do this in the sp package docs, but I might have missed it. -- View this message in context: http://r.789695.n4.nabble.com/sample-points-sp-package-tp4372673p4372673.html Sent from the R help mailing list archive at Nabble.com.
sample points - sp package
2 messages · Ana, MacQueen, Don
I suggest you ask this question on r-sig-geo. And it would be best if you could create a small self-contained example. For example, what class of object is dataset2? Is there any reason to expect that the coordinates of the sample will be exactly the same as any of the coordinates in dataset2? Probably, you will have to find a function that will find the point in dataset2 that is nearest to each point in your sample. I believe there are a few such functions among the R spatial packages, but I don't remember any names. -Don
Don MacQueen Lawrence Livermore National Laboratory 7000 East Ave., L-627 Livermore, CA 94550 925-423-1062 On 2/9/12 4:39 AM, "anaraster" <rrasterr at gmail.com> wrote: >When I make a sample in sp, for example a random samping of 5 points in >dataset1: > >sample.dataset1=spsample(dataset1, n = 5, "random") > >I have a sp object for the selected sampling... > >My question is : How can I extract from dataset2 the points & data for the >coordinates(sample.dataset1) ? > >The dataset2 would be an object with the same area and coordinate system, >but I would like to extract for the coordinates of sample.dataset1 the >data >in each point for dataset2. > >I didn't found a way to do this in the sp package docs, but I might have >missed it. > >-- >View this message in context: >http://r.789695.n4.nabble.com/sample-points-sp-package-tp4372673p4372673.h >tml >Sent from the R help mailing list archive at Nabble.com. > >______________________________________________ >R-help at r-project.org mailing list >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide >http://www.R-project.org/posting-guide.html >and provide commented, minimal, self-contained, reproducible code.