How to find distance in a for loop using d=distance

I have lat and long points and I want to see the total distance between all of the points. What im trying to figure out is how to continue this in a for loop, here is my code:

for i = 1:numel(TrackLat)
    d = distance(TrackLat(1,:), TrackLong(1,:), TrackLat(2,:), TrackLong(2,:), wgs84);
end

So right now im adding the first point to the second point and I get the correct distance, now I want to add the second point to the third point and so on. Im working with a small subset of a dataset with approx. 100000 points, at the end I want to concat all of this together to get total distance traveled. I thought maybe this would work:

for i = 1:numel(TrackLat)
    d = distance(TrackLat(i,:), TrackLong(i,:), TrackLat(i+1,:), TrackLong(i+1,:), wgs84);
end

but I get this error:

Index in position 1 exceeds array bounds. Index must not exceed 32.

Error in untitled7 (line 69)
    d = distance(TrackLat(i,:), TrackLong(i,:), TrackLat(i+1,:), TrackLong(i+1,:), wgs84);
                                                ^^^^^^^^^^^^^^

I assume thats because when I get to the end of the loop its trying to add the last point to a point that doesnt exist. How can I go about this to calculate the total distance between a bunch of lat and long points? Thanks!

Answer 1

[Mathieu NOE]

hello

• the loop must stop one index value before the end
• also I would suggest you index the d value so you get (numel(TrackLat) - 1) arc lengths
• use sum to compute the total distance

code should be like :

for i = 1:numel(TrackLat)-1
    d(i) = distance(TrackLat(i,:), TrackLong(i,:), TrackLat(i+1,:), TrackLong(i+1,:), wgs84);
end
d_total = sum(d);  % total distance