distance

I am trying to use the distHavrsine function in R, inside a loop to calculate the distance between some latitude and longitude coordinates for a several hundred rows. In my loop I have this code: if ((distHaversine(c(file[i,"long"], file[i,"lat"]), c(file[j,"long"], file[j,"lat"]))) < 50 ) after which if the distance is less than 50 meters i want it to record those rows, and where the latitude and longitude coordinates it is referencing look like: 0.492399367 30.42530045 and 0.496899361 30.42497045 but i get this error Error in .pointsToMatrix(p1) : latitude > 90 i get this error "Error in

For some reason a friend and myself were talking about calculating the distance between yourself (laptop, phone, etc.) and an AP based of the info you get from the devices (RSSI, freq, SNR, etc...). So, after spending sometime researching about trilateration, triangulation, and free-space path loss. (with the help of some blog posts and wiki) I was able to get a distance in meters from the AP to my laptop and the results were a lot better then what I thought they would be. Whenever I'm in the same room or there's a line of sight to the AP, the accuracy is about a foot. But now, I want to take

I am trying to compute the Mahalanobis distance between each observations of a dataset dat , where each row is an observation and each column is a variable. Such distance is defined as: I wrote a function that does it, but I feel like it is slow. Is there any better way to compute this in R ? To generate some data to test the function: generateData <- function(nObs, nVar){ library(MASS) mvrnorm(n=nObs, rep(0,nVar), diag(nVar)) } This is the function I have written so far. They both work and for my data (800 obs and 90 variables), it takes approximatively 30 and 33 seconds for the method =

I am creating an application that requires the user to input two places (Postal codes). My application will calculate the driving-distance between these two points ad output the result. The user has the option of adding Way-Points. I think I would have to use the google maps API and get an xml file with the result and then parse the xml file. Can anyone help me because i not sure how to do this. Appreciate all help. Example... Start: BR1 1LR Waypoint: BR2 0LH Waypoint: BR3 4AY Destination: BR1 1LR Yes you can calculate the distance ,for that you need to have the latitude and longitude to get

for a geo-based online game I'm looking for an algorithm which finds the shortest distance between a specified point and a known path connected by x/y-coordinates, so that I can kill all redundant points/nodes. A link or keyword for this algorithm would help me a lot! thanks for reading For better understanding: Are you wanting to calculate this in order to say something like "if the point-to-path distance is zero, then remove the point"? If so, then there is probably an easier way to remove redundant nodes. Take the points three at a time (call them A , B , and C ). Calculate the angle