[R-sig-Geo] Highway Distance matrix

Hi, How can I compute a distance matrix of points (citys) based on a highway base map? Regards in advance, Raphael Saldanha saldanha.plan...@gmail.com [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org

Re: [R-sig-Geo] SpatStat: creating window from quadrats

Dear Marcelino, Thanks for your reply... It works until I have to use 'boardquadrats' as my window. boardquadrats is a list including binary image mask, and i have to convert it in a window, am I right? Reading the book from Baddeley, it seems I have to convert it in a matrix and then only in

Re: [R-sig-Geo] Highway Distance matrix

Hi, I agree with Jeremy, but it seems that it's not very handy to use igraph to compute the shortest path. I have developed a package shp2graphto transform a road network data set from a SpatialLinesDataFrame. Based on this, I have writen a guide to compute the shorest path in R, which is

Re: [R-sig-Geo] Highway Distance matrix

On Thu, 4 Aug 2011, lubinbin...@gmail.com wrote: Hi, I agree with Jeremy, but it seems that it's not very handy to use igraph to compute the shortest path. I have developed a package shp2graphto transform a road network data set from a SpatialLinesDataFrame. Based on this, I have writen a

[R-sig-Geo] histogram of SpatialGridDataFrame values

Hi, So I've loaded a DEM into a SpatialGridDataFrame, and I can plot it etc. However, I would like to make a histogram of the pixel values (or just a random sample of the pixel values) to help make decisions about the color scheme etc. Is there an easy way to do this? Cheers! Nick --

Re: [R-sig-Geo] histogram of SpatialGridDataFrame values

Nevermind, got it: as.matrix(dem) On 8/4/11 5:06 PM, Nick Matzke wrote: Hi, So I've loaded a DEM into a SpatialGridDataFrame, and I can plot it etc. However, I would like to make a histogram of the pixel values (or just a random sample of the pixel values) to help make decisions about the

Re: [R-sig-Geo] histogram of SpatialGridDataFrame values

More simply perhaps you can get any column by name or number like any data.frame - this gives all pixel values for the first attribute (assuming first colname is the default - use names(dem) to find out): dem$band1 dem[[1]] On Fri, Aug 5, 2011 at 12:04 PM, Nick Matzke mat...@berkeley.edu

[R-sig-Geo] Grouping linked points

Hi, I have a list of the links shared by n points. Each element of the list represents the ID of a point and the entries for each element indicate the ID's of the points that it is linked with. I would like to group points via their ID's based on these links. There are an unknown number of