www.pudn.com > SerialGPS.zip > ComputeTrackStats.m

function [ distance, time ] = ComputeTrackStats(track) 
% COMPUTETRACKSTATS Compute track log statistics 
% 
% Compute the length of the track, and the time spent traversing it. 
% Sometimes the time may be zero, because Garmin GPS units remove the 
% timestamp from saved track logs (though they maintain it in the  
% active log). 
 
distance = 0; 
time = 0; 
for i=1:length([track.waypoints.lat])-1 
    distance = distance + SphericalDistance(track.waypoints(i), track.waypoints(i+1)); 
end 
% Time stamp stored as seconds, simply subtract end from beginning to 
% get duration.  
seconds = track.waypoints(i).time - track.waypoints(1).time; 
% Covert to hours 
time = seconds / 3600; 
 
function d = SphericalDistance(point1, point2) 
% SPHERICALDISTANCE Compute the distance between two points on the Earth's  
% surface Earth's radius: 
%   3437.74677 statue miles 
%   6378 kilometers 
%   3963 normal miles 
 
% Convert to radians. 
deg2rad = (180/pi);  
lat1 = point1.lat / deg2rad;  
long1 = point1.long / deg2rad; 
lat2 = point2.lat / deg2rad; 
long2 = point2.long / deg2rad; 
 
% Compute distance in miles 
r = 3963; 
d = acos( sin(lat1) * sin(lat2) + ... 
          cos(lat1)*cos(lat2)*cos(long2-long1) ) * r;