similar to: Polygon-like interactive selection of plotted points

In R's maptools package, is there a built-in function to test if a given point is "inside" a given polygon on the map? The map was loaded from an ESRI Shapefile. The point's latitude and longitude are known. Thank you! Aleks -- ------------------------ Aleksandr Andreev Fulbright Fellow Graduate School of Management St Petersburg State University

Sorry, this is probably quite an easy question, but I'm new to R and couldn't find the answer anywhere. I'm using geoR and geoRglm, but can't figure out how to get a border in my geodata object. Does this need to be defined when I'm importing my data, or afterwards, and how do I go about doing this? Thanks -- View this message in context:

I am modeling a trend surface using trmat and want to trim the resulting matrix to the area enclosed by my real data (i.e., remove all the extrapolated areas). I was using chull and in.chull to calculate the convex hull and change all the other values created by trmat to NA. However, my real data has portions that are slightly concave so chull would give me slivers that are extrapolations from

Dear all, Does anyone know of a function that calculates the area of the outer polygon constructed from a data frame with co-ordinates? For example, library(splancs) test = rbind(c(0,0), c(10,0),c(10,10),c(0,20)) plot(test) areapl(test) [1] 150 This is OK, but I want the same area to be returned (150) when adding yet another co-ordinate in the middle of the polygon: test = rbind(c(0,0),

Hi, I seek to identify those points in/outside a multidimensional convex hull (geometry::convhulln). Any suggestions? Background just in case I'm going down a really wrong road: Given an observed data set with one dependent/observed variable (Y) and multiple (3 to 10) independent/design variables (X1, X2, ...) I want to increase the number of points by interpolating. I'm using

Hello, I am trying to draw a convex-polygon (envelope) connecting the outer points (of a particular class) in a scatter plot [which I want to do to illustrate the range of a particular type of samples in an ordination plot]. Is there any function to plot this kind of polygon? Kind regards Zlatko Petrin

Hello, I have the contour of the shoreline of a lake. I have measured data points away from the lake shore signifying a particular depth. The data is not ordered as a polygon and hence trying to draw it creates a series of lines all over the place. I would like to turn the points into a ordered set that results in a smooth polygon. I have tried a "nearest point" approach. An example

What is plot.new? and how can i get it to work so i can load other data? > library(splancs) > area = 6*4 > lambda = 1.5 > N = rpois(1,lambda*area) > u = runif(N,-2,4) > v = runif(N,0,4) > plot(u,v,asp=1) > h = chull(u,v) > h = c(h,h[1]) > plot(u[h],v[h],"1",asp=1) Error in plot.xy(xy, type, ...) : invalid plot type '1' >

Sorry, I did not make my question clear. Since I have a point theme with many points, some of them may clump together. the problems here are: 1. how to find clumps in a point theme? 2. the convex-hull extension I found only deal with all the points in a theme at each time? how to make each convex hull around each point clump automatically? Thanks. Xiaohua On 5/12/06, Bob Booth <bbooth

Hello everybody, I search a function which returns the contour of map with levels like contourLines, but I would like this function return the border of the map too, because the function contourLines cannot consider the corner of the map and it is not adapted to fill polygon after that. Thanks in advance Pierre Bruyer

Dear R gurus and users, I seem to have problem finding the right tool for plotting convex hulls over 2D plots, after a cluster analysis. In fact I would like to draw a convex hull in 2D for a generic group of points. I found a "convhulln", but this doesn't seem to give me a convex hull. Here is what I do: > library(mvtnorm) > Mean <- c(2,1) > Sigma <-

Dear R-users, Suppose I have the following x-y coordinates which give the boundaries of a polygon: > x <- c(5,4,5,9,6,6,4,7,10,7,10,4,10) > y <- c(6,3,2,6,3,7,5,4,4,7, 5,4, 6) I would like to plot the following graph: > plot(x,y) > ord <- c(7,12,2,3,5,8,9,11,13,4,10,6,1) > polygon(x[ord],y[ord]) How I can obtain the above ordering (in the example an anti-clockwise

Dear all, I would like to plot credible interval for a function estimate in R. I would like to plot the credible intervals as shaded region using polygon function. Does anyone ever used that? I tried several times but I could not obtain the right figure. xis=sort(xi,decreasing=TRUE) plot(xi,fm) polygon(c(xi,xis),c(f05m,f95m)) The above piece of code produces something else. Many thanks in

Hello all! I have a problem to draw a polygon with R. My data is like this> Year Nb.series Perc.pos Perc.neg Nature RGV_mean RGV_sd neg poz 1 1901 1 0.00 0.00 0 4.29 NA 0.00 0.00 2 1902 1 100.00 0.00 1 16.47 NA 0.00 100.00 3 1903 1 100.00 0.00 1 31.31 NA 0.00 100.00 4 1904 1 0.00 0.00 0 -9.62 NA 0.00 0.00 5 1905 1 0.00 100.00 -1 -22.55 NA -100.00 0.00 6 1906 1 0.00 100.00 -1 -12.09 NA

Hello dear members of R-help and R-core mailing list, I am not sure if this request is a "ticket" that should be filled somewhere outside the mailing list. If so, I apologize for not doing and would like to know where I should have filled it. And to the subject matter: I would like to use a command like this: plot(c(1,8), 1:2, type="n") polygon(1:7, c(2,1,2,NA,2,1,2),

Hello dear members of R-help and R-core mailing list, I am not sure if this request is a "ticket" that should be filled somewhere outside the mailing list. If so, I apologize for not doing and would like to know where I should have filled it. And to the subject matter: I would like to use a command like this: plot(c(1,8), 1:2, type="n") polygon(1:7, c(2,1,2,NA,2,1,2),

Hello, Does anyone know how a function to find automaticly the border (polygon) of a cloud of points? It is for a PCA kind of analysis, where I wanted to present as the limits for each group, instead of all points... thank you in advance Marta

Dear R-helpers, an rgl-ers in particular, what is the easiest way to plot a section of a plane in 3D, that is given by the xyz coordinates of the outline? Suppose I have a polygon - which I know for sure is a set of coordinates on the same plane. One method I found is to use surf.tri from the geometry package, and then plot the triangles with rgl.triangles. This method is not perfect though,

Dear R users, I'm trying to extract from a given matrix (GROUP) the coordinates of the vertices of the different groups (i.e. 3, 7, 1 . . .) to plot the polygons to delineate the area in which each group "wins" and colour it diferentially. I can make a simple point plot, but I would like to add polygons with full colored area. The example is with a 5x5 matrix, but I'm working

Hi there, I want to integrate a function over an irregular polygon. Is there any function which can implement this easily? Otherwise, I am thinking of divide the polygon into very small rectangles and use "adapt" to approximate it. Do you have any suggestions to get the fine division? Any advice is appreciated. Haiyong