github/recorder
1
0
Fork 0
mirror of https://github.com/owntracks/recorder.git synced 2026-02-13 20:49:51 +00:00
Code Issues Packages Projects Releases Wiki Activity

add haversine

Browse Source
This commit is contained in:
Jan-Piet Mens
2016-01-05 09:40:16 +01:00
parent 2e8b292675
commit 8fb2c14599
2 changed files with 21 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
util.c
View File

@@ -34,6 +34,7 @@
#include <fcntl.h>
#include <errno.h>
#include <stdarg.h>
#include <math.h>
#ifndef LINESIZE
# define LINESIZE 8192
@@ -557,3 +558,22 @@ void lowercase(char *s)
*bp = tolower(*bp);
}
}
/* http://rosettacode.org/wiki/Haversine_formula#C */
/* Changed to return meters instead of KM (* 1000) */
#define R 6371
#define TO_RAD (3.1415926536 / 180.0)
double haversine_dist(double th1, double ph1, double th2, double ph2)
{
double dx, dy, dz;
ph1 -= ph2;
ph1 *= TO_RAD, th1 *= TO_RAD, th2 *= TO_RAD;
dz = sin(th1) - sin(th2);
dx = cos(ph1) * cos(th1) - cos(th2);
dy = sin(ph1) * cos(th1);
return asin(sqrt(dx * dx + dy * dy + dz * dz) / 2) * 2 * R * 1000;
}

1
util.h
View File

@@ -33,5 +33,6 @@ void olog(int level, char *fmt, ...);
void geohash_setprec(int precision);
int geohash_prec(void);
void lowercase(char *s);
double haversine_dist(double th1, double ph1, double th2, double ph2);
#endif