Re: [R] Points inside a polygon
On 12/01/12 17:28, Hasan Diwan wrote: I have a list of bounds for a series of polygons. I do understand the formula to determine whether point i is within polygon X (X[x1]< i[x] & X[x2]> i[x]& X[y1]< i[y]& X[y2]> i[y]), and I can apply this throughout the dataset. However, this naive algorithm doesn't scale very well. The data set contains 10,000 points consisting of (n,e) pairs where I'm interested in which are inside polygons denoted by vertices (V[x1]/V[y1],V[x2],V[y2]). Is there a shortcut to accomplish this goal? Many thanks! -- You could use the function inside.owin() in the "spatstat" package (after appropriately reconfiguring your polygons as objects of class "owin"; something like w <- owin(poly=plygn) where "plygn" is your polygon). You could also use the undocumented function inside.xypolygon(). cheers, Rolf Turner __ R-help@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.
Re: [R] Points inside a polygon
On Wed 11 Jan 2012 08:28:03 PM PST, Hasan Diwan wrote: I have a list of bounds for a series of polygons. I do understand the formula to determine whether point i is within polygon X (X[x1]< i[x] & X[x2]> i[x]& X[y1]< i[y]& X[y2]> i[y]), and I can apply this throughout the dataset. However, this naive algorithm doesn't scale very well. The data set contains 10,000 points consisting of (n,e) pairs where I'm interested in which are inside polygons denoted by vertices (V[x1]/V[y1],V[x2],V[y2]). Is there a shortcut to accomplish this goal? Many thanks! -- H Check out the splancs package. particularly the inout function. Justin __ R-help@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.
[R] Points inside a polygon
I have a list of bounds for a series of polygons. I do understand the formula to determine whether point i is within polygon X (X[x1] < i[x] & X[x2] > i[x] & X[y1] < i[y] & X[y2] > i[y]), and I can apply this throughout the dataset. However, this naive algorithm doesn't scale very well. The data set contains 10,000 points consisting of (n,e) pairs where I'm interested in which are inside polygons denoted by vertices (V[x1]/V[y1],V[x2],V[y2]). Is there a shortcut to accomplish this goal? Many thanks! -- H -- Sent from my mobile device Envoyait de mon portable __ R-help@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.
