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User Input Error? Using input in a function

Asked by Olivia Colombo on 27 Feb 2019
Latest activity Answered by Stephan
on 28 Feb 2019
I am trying to use input to make a functiont that calculates the great circle distance between two sets of coordinates on the surface of the Earth. The problem is I am getting an error on the part that takes input (line 4), long before I get to the calculations. What am I doing wrong?
I've attached the code as well as example coordinates to check it.

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Error using mydistance (line 4)
Error: Invalid expression. Check for missing multiplication operator,
missing or unbalanced delimiters, or other syntax error. To construct
matrices, use brackets instead of parentheses.
exactly what input are you typing in in response to the prompt ?
I've been testing it with: (with and without various degree symbols)
37N, 76W 37N 9W

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1 Answer

Answer by Stephan
on 28 Feb 2019

Hi,
try:
result = mydistance
function d = mydistance
prompt = 'Input coordinates between which you want to find the great circle distance (XºN, XºW XºN, XºW): \n';
getridof = ["N","W",",",char(176)];
x = input(prompt,'s');
x = double(string(split(replace(x,getridof,""))));
a = acos(sin(deg2rad(x(1)))*sin(deg2rad(x(3)))+cos(deg2rad(x(1)))*cos(deg2rad(x(3)))*cos(abs(deg2rad(x(2)))-deg2rad(x(4))));
d = a*.6371;
disp(['The great circle distance in km is: ',num2str(d)])
end
for input:
Input coordinates between which you want to find the great circle distance (XºN, XºW XºN, XºW):
37°N, 76°W 37°N, 9°W
the result is:
The great circle distance in km is: 0.58165
result =
0.5817
Best regards
Stephan

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