Re: [R] R_Calculating Thiessen weights for an area with irregular boundary
It certainly is! Thank you. Cheers, Mano On Thu, Apr 23, 2015 at 12:02 AM, Rolf Turner r.tur...@auckland.ac.nz wrote: On 22/04/15 22:43, Manoranjan Muthusamy wrote: SNIP 4. SNIP How can I show the Dirichlet tile names (i.e. 1,2,3,,8) in the plot? There's no built-in way at the moment as far as I can tell. One way to get the tiles to be labelled/numbered in the plot would be: plot(dX) text(X,labels=1:npoints(X)) Slightly sexier: cents - as.data.frame(t(sapply(tiles(dX),centroid.owin))) plot(dX) text(cents,labels=1:nrow(cents)) Is this satisfactory? cheers, Rolf Turner -- Rolf Turner Technical Editor ANZJS Department of Statistics University of Auckland Phone: +64-9-373-7599 ext. 88276 Home phone: +64-9-480-4619 [[alternative HTML version deleted]] __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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] R_Calculating Thiessen weights for an area with irregular boundary
1. Apologies for the lousy presentation of the data and thank you for your feedback. I promise it will not happen again. 2. Thank you 3. Yes, exactly! 4. Exactly what I wanted without much hassle. Thank you very much. Time to explore the package 'spatstat'. How can I show the Dirichlet tile names (i.e. 1,2,3,,8) in the plot? Cheers, Mano On Tue, Apr 21, 2015 at 11:33 PM, Rolf Turner r.tur...@auckland.ac.nz wrote: (1) The manner in which you presented your data was a total mess. If you ask for help, please have the courtesy to present your data in such a manner that a potential helper can access it without needing to do a great deal of editing and processing. Like so: pts - as.data.frame(matrix(c(415720,432795,415513,432834,415325, 432740,415356,432847,415374,432858, 415426,432774,415395,432811,415626, 432762),ncol=2,byrow=TRUE)) names(pts) - c(x,y) bdry - as.data.frame(matrix(c(415491,432947,415269,432919,415211, 432776,415247,432657,415533,432657, 415781,432677,415795,432836,415746, 432937),ncol=2,byrow=TRUE)) names(bdry) - c(x,y) (2) Well, at least you presented a usable data set (even though the presentation was lousy) which is better than what most posters do. And you asked a partially clear question. (3) I do not know what you mean by Thiessen weights. I am guessing that these are the areas of the Dirichlet tiles (Thiessen polygons), intersected with the boundary polygon (i.e. observation window). (4) If my guess is correct, the following should accomplish the desired task: require(spatstat) # You will (probably) need to install spatstat first. W - owin(poly=bdry) X - as.ppp(pts,W=W) plot(X) # Just to make sure it looks right. dX - dirichlet(X) plot(dX) # Just to make sure . sapply(tiles(dX),area.owin) HTH cheers, Rolf Turner On 22/04/15 02:50, Manoranjan Muthusamy wrote: Hi R users, I want to calculate Thiessen weights to compute areal rainfall from number of point measurements. I am using R and thanks to some previous question in the same topic, I got to know that I can usedeldir. But the problem is my boundary polygon is not a rectangle; it's an irregular polygon (it's a catchment boundary derived using ArcGIS). But in deldir the boundary can only be a rectangle. Are there any other packages where I can calculate Thiessen weights of an area covered by an irregular boundary? Given below are my measurement points (meas_points) and coordinates of a (simplified) boundary polygon(boundary) meas_points X Y[1,] 415720 432795[2,] 415513 432834[3,] 415325 432740[4,] 415356 432847[5,] 415374 432858[6,] 415426 432774[7,] 415395 432811[8,] 415626 432762 boundary x y[1,] 415491 432947[2,] 415269 432919[3,] 415211 432776[4,] 415247 432657[5,] 415533 432657[6,] 415781 432677[7,] 415795 432836[8,] 415746 432937 Any help is really appreciated. Thanks. -- Rolf Turner Technical Editor ANZJS Department of Statistics University of Auckland Phone: +64-9-373-7599 ext. 88276 Home phone: +64-9-480-4619 [[alternative HTML version deleted]] __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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] R_Calculating Thiessen weights for an area with irregular boundary
On 22/04/15 22:43, Manoranjan Muthusamy wrote: SNIP 4. SNIP How can I show the Dirichlet tile names (i.e. 1,2,3,,8) in the plot? There's no built-in way at the moment as far as I can tell. One way to get the tiles to be labelled/numbered in the plot would be: plot(dX) text(X,labels=1:npoints(X)) Slightly sexier: cents - as.data.frame(t(sapply(tiles(dX),centroid.owin))) plot(dX) text(cents,labels=1:nrow(cents)) Is this satisfactory? cheers, Rolf Turner -- Rolf Turner Technical Editor ANZJS Department of Statistics University of Auckland Phone: +64-9-373-7599 ext. 88276 Home phone: +64-9-480-4619 __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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] R_Calculating Thiessen weights for an area with irregular boundary
(1) The manner in which you presented your data was a total mess. If you ask for help, please have the courtesy to present your data in such a manner that a potential helper can access it without needing to do a great deal of editing and processing. Like so: pts - as.data.frame(matrix(c(415720,432795,415513,432834,415325, 432740,415356,432847,415374,432858, 415426,432774,415395,432811,415626, 432762),ncol=2,byrow=TRUE)) names(pts) - c(x,y) bdry - as.data.frame(matrix(c(415491,432947,415269,432919,415211, 432776,415247,432657,415533,432657, 415781,432677,415795,432836,415746, 432937),ncol=2,byrow=TRUE)) names(bdry) - c(x,y) (2) Well, at least you presented a usable data set (even though the presentation was lousy) which is better than what most posters do. And you asked a partially clear question. (3) I do not know what you mean by Thiessen weights. I am guessing that these are the areas of the Dirichlet tiles (Thiessen polygons), intersected with the boundary polygon (i.e. observation window). (4) If my guess is correct, the following should accomplish the desired task: require(spatstat) # You will (probably) need to install spatstat first. W - owin(poly=bdry) X - as.ppp(pts,W=W) plot(X) # Just to make sure it looks right. dX - dirichlet(X) plot(dX) # Just to make sure . sapply(tiles(dX),area.owin) HTH cheers, Rolf Turner On 22/04/15 02:50, Manoranjan Muthusamy wrote: Hi R users, I want to calculate Thiessen weights to compute areal rainfall from number of point measurements. I am using R and thanks to some previous question in the same topic, I got to know that I can usedeldir. But the problem is my boundary polygon is not a rectangle; it's an irregular polygon (it's a catchment boundary derived using ArcGIS). But in deldir the boundary can only be a rectangle. Are there any other packages where I can calculate Thiessen weights of an area covered by an irregular boundary? Given below are my measurement points (meas_points) and coordinates of a (simplified) boundary polygon(boundary) meas_points X Y[1,] 415720 432795[2,] 415513 432834[3,] 415325 432740[4,] 415356 432847[5,] 415374 432858[6,] 415426 432774[7,] 415395 432811[8,] 415626 432762 boundary x y[1,] 415491 432947[2,] 415269 432919[3,] 415211 432776[4,] 415247 432657[5,] 415533 432657[6,] 415781 432677[7,] 415795 432836[8,] 415746 432937 Any help is really appreciated. Thanks. -- Rolf Turner Technical Editor ANZJS Department of Statistics University of Auckland Phone: +64-9-373-7599 ext. 88276 Home phone: +64-9-480-4619 __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
