search for: crossdist

...lly, rectangular) tophat smoothing routine based on altering the already available KDE2D. I would be keen to implement a circular tophat routine also, however this appears to be much more difficult to write efficiently (I have a routine, but it's very slow). I tried to create one based on using crossdist to create a distance matrix between my data and the sampling grid, but it doesn't take a particularly large amount of data (or hi res grid) for memory to be a big problem. The 2D density routines I have been able to find either don't support a simple tophat, or don't use the absolute di...

...myself already, but it's horrificly slow with a dataset of 40k+ points in one set, and a 700 in the other. A very inefficient example of what I'm looking for: for (pt in X$idx) { proximity[i] = euclidian_dist(X[pt]$x, X[pt]$y, Y$x, Y$y) < X$threshold i = i+1 } Perhaps crossdist() in spatstat is what I should use, and then code a comparison with X$threshold after the cross-distances are computed. However, I was wondering if there was another tool I should be considering. Any and all thoughts are very welcome. Thanks in advance. Thanks, Allie -- Alexander Shenkin PhD Ca...

Hi all I am trying to determine the distances between two datasets of x and y points. The number of points in dataset One is very small i.e. perhaps 5-10. The number of points in dataset Two is likely to be very large i.e. 20,000-30,000. My initial approach was to append the first dataset to the second and then carry out the calculation: dists <- as.matrix(dist(gis data from 2 * datasets))

Hi there, I have two data sets, one of locations at different elevations (x,y,z) and the other of points that make up topographic contours (also x,y,z). I have used: result<-apply(distppll(data2,cbind(topocon[-nrow(topocon),],topocon[-1,])),1,min) where 'data2' are my measurement coordinates (x, y) and 'topocon' are my topographic contours (x,y). While this gives me an output

Dear R-user, Is there a way in R to locate the nearest 5 indices to a station, based on distances in a distance matrix. In other words i want to have nearest stations based on the distances in the matrix. The distance matrix, i have, has dimension 44*44. Thankyou very much in advance Elisa [[alternative HTML version deleted]]

Hello, I want to know if there are some functions or packages to solve differential and integral equation using R. Thanks. Shao chunxuan. [[alternative HTML version deleted]]