geographic-distance

问题 I am able to plot a map and caption a specific point: library(maps) map("state") text(-80.83,35.19,"Charlotte",cex=.6) I can also plot a circle centered around that point: symbols(-80.83,35.19,circles=2, add=TRUE) However, I would like to control the size of the circle. In particular, I want to draw a circle with a radius of 100 mile around multiple locations contained in a data.frame, matrix, or list. 回答1: You can write a function to customize how you want the circle to look. For example:

问题 I'm trying to calculate distance between two points, using latitude longitude and altitude (elevation). I was using euklides formula in order to get my distance: D=√((Long1-Long2)²+(Lat1-Lat2)²+(Alt1-Alt2)²) My points are geographical coordinates and ofcourse altitude is my height above the sea. I only have lat and lng, I'm using GOOGLE API Elevation to get my altitude. I'm developing an application which calculates my traveled distance (on my skis). Every application which I have used, gets