Finding the distance traveled using GPS Coordinates

I am trying to calculate the distance traveled using GPS coordinates from a run. In my first attempt, I am using this code I found. I am extracting data from a google sheet containing the Times, Acceleration X, Y, & Z, latitude and longitude values. I am now getting the error:

Undefined function 'cos' for input arguments of type 'char'.

Error in project (line 66)

a=sin((deltaLat)/2)^2 + cos(lat1)*cos(lat2) * sin(deltaLon/2)^2;

Please let me know how to fix this error OR if you have any other suggestions on how to calculate distance using the 4650x60 sheet I am pulling the data from

% DOCID='1dqtn5aTdOIuhcLbz1coBazoInQ9a2XNJcb4rUf1BdqM';
% Outdoor_Data= GetGoogleSpreadsheet(DOCID);
% x1=Outdoor_Data(:,2); %the first runs latitude values
% y1=Outdoor_Data(:,3); %the first runs longitude values
% x2=Outdoor_Data(:,8); %the second runs latitude values
% y2=Outdoor_Data(:,9); %the second runs longitude values
% x3=Outdoor_Data(:,14); %the third runs latitude values
% y3=Outdoor_Data(:,15); %the third runs longitude values
% x4=Outdoor_Data(:,20); %the fourth runs latitude values
% y4=Outdoor_Data(:,21); %the fourth runs longitude values
% x5=Outdoor_Data(:,26); %the fifth runs latitude values
% y5=Outdoor_Data(:,27); %the fifth runs longitude values
function [d1km d2km]=lldistkm(latlon1,latlon2)
% format: [d1km d2km]=lldistkm(latlon1,latlon2)
% Distance:
% d1km: distance in km based on Haversine formula
% (Haversine: http://en.wikipedia.org/wiki/Haversine_formula)
% d2km: distance in km based on Pythagoras’ theorem
% (see: http://en.wikipedia.org/wiki/Pythagorean_theorem)
% After:
% http://www.movable-type.co.uk/scripts/latlong.html
%
% --Inputs:
%   latlon1: latlon of origin point [lat lon]
%   latlon2: latlon of destination point [lat lon]
%
% --Outputs:
%   d1km: distance calculated by Haversine formula
%   d2km: distance calculated based on Pythagoran theorem
%
% --Example 1, short distance:
%   latlon1=[-43 172];
%   latlon2=[-44  171];
%   [d1km d2km]=distance(latlon1,latlon2)
%   d1km =
%           137.365669065197 (km)
%   d2km =
%           137.368179013869 (km)
%   %d1km approximately equal to d2km
%
% --Example 2, longer distance:
%   latlon1=[-43 172];
%   latlon2=[20  -108];
%   [d1km d2km]=distance(latlon1,latlon2)
%   d1km =
%           10734.8931427602 (km)
%   d2km =
%           31303.4535270825 (km)
%   d1km is significantly different from d2km (d2km is not able to work
%   for longer distances).
%
% First version: 15 Jan 2012
% Updated: 17 June 2012
%--------------------------------------------------------------------------
DOCID='1dqtn5aTdOIuhcLbz1coBazoInQ9a2XNJcb4rUf1BdqM';
Outdoor_Data= GetGoogleSpreadsheet(DOCID);
x1=Outdoor_Data{:,2}; %the first runs latitude values
y1=Outdoor_Data{:,3}; %the first runs longitude values
radius=6371;
lat1=x1(2);
lat2=x1(3);
lon1=y1(2);
lon2=y1(3);
deltaLat=lat2-lat1;
deltaLon=lon2-lon1;
a=sin((deltaLat)/2)^2 + cos(lat1)*cos(lat2) * sin(deltaLon/2)^2;
c=2*atan2(sqrt(a),sqrt(1-a));
d1km=radius*c;    %Haversine distance

x=deltaLon*cos((lat1+lat2)/2);
y=deltaLat;
d2km=radius*sqrt(x*x + y*y); %Pythagoran distance

end

Answer 1

[Walter Roberson]

https://www.mathworks.com/matlabcentral/fileexchange/39915-getgooglespreadsheet

GetGoogleSpreadsheet() from File Exchange returns cell arrays of character vectors. It makes no attempt at all to convert to numeric.

x1 = str2double(Outdoor_Data(:,2)); %the first runs latitude values
y1 = str2double(Outdoor_Data(:,3)); %the first runs longitude values

[Mary Jean Savitsky]

Thank you so much!