Do I need nested loops?

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Bob Murphy
Bob Murphy on 17 Mar 2016
Commented: Bob Murphy on 22 Mar 2016
I am trying to create a small script that will allow me to expand the perimeter based off coordinates. The program is running through the variables correctly when I look at the workspace, but I can't get it to write the results to the structure multiple times. It will only write to the structure once. Am I missing a nested loop?
load 'lat_lon.mat'
new_coord = [];
for i = 1:length(lat_lon)
1
new_coord.Lat = [lat_lon(:,[1])];
new_coord.Lon = [lat_lon(i:,[2])];
2
%Finds the radius of the Earth at given latitude
radius = 6372 * cos(lat_lon(i,[1])/180 * pi)
3
%Converts given perimeter expansion to degrees
lat_nat_deg = nm2deg(3.5, radius);
new_coord.lat_exp = [lat_nat_deg];
nat_deg = nm2deg(3.5);
new_coord.lon_exp = [nat_deg];
4
new_coord.latitude = [lat_lon(i,[1]) + lat_nat_deg];
5
new_coord.longitude = [lat_lon(i,[2]) + nat_deg]
end
The lat_lon.mat is :
Lat_Long = [60.8427194, -042.7969500; ...
60.8646972, -042.5323889; ...
60.7640417, -042.5178639; ...
60.5882139, -042.8185056; ...
60.8080111, -042.8507500; ...
60.8069889, -042.8374167; ...
60.8083028, -042.8278361; ...
60.8114056, -042.8186167; ...
60.8152306, -042.8117389; ...
60.8203694, -042.8055667; ...
60.8256528, -042.8013611; ...
60.8315167, -042.7985083; ...
60.8374056, -042.797078; ...
60.8427194, -042.7969500];

Accepted Answer

Chad Greene
Chad Greene on 17 Mar 2016
The loop you've written overwrites the results each time through the loop. Any information you want to log such as newcoord.latitude must be indexed to i. (Better yet, change i to k because i is the imaginary unit in Matlab and defining i as a variable can occasionally cause errors.)
Here are two ways you can organize your structure:
for k = 1:10
newcoord.lat{k} = randi(90,1,2);
anotherway(k).lat = randi(90,1,2);
end
  1 Comment
Bob Murphy
Bob Murphy on 22 Mar 2016
That's exactly what I was trying to do! If I wanted to save the results as a double like the provided coordinates were, is there a simple edit to do that?

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