MATLAB Answers

## Loop to carry out calculation for pairs 1 and 2, then pairs 2 and 3 and so on.

Asked by BOB

### BOB (view profile)

on 21 Aug 2018
Latest activity Commented on by Torsten

### Torsten (view profile)

on 21 Aug 2018
Accepted Answer by Torsten

### Torsten (view profile)

Hi,
I have two 8x1 matrices. One matrix is list of longitude coordinates (Final_Longitude_Values). The other matrix is the corresponding latitude coordinates (Final_Latitude_Values).
I want to calculate the distance between the first pair and the second pair, and then the second pair and the third pair, and so on until I have come to the end of each matrix.
I have written the following code in an attempt to automate this process:
{for j = 1:length(Final_Latitude_Values)
latlon1=[(Final_Latitude_Values(j)) (Final_Longitude_Values(j))];
latlon2=[(Final_Latitude_Values(j+1) (Final_Longitude_Values(j+1))];
end
[d1km d2km]=distance(latlon1,latlon2);
Segment_Distance = d2km}
However, the index exceeds the matrix dimensions, and I can't seem to figure out how to work around this issue. If anyone could correct my code it would be much appreciate.
Thanks

#### 0 Comments

Sign in to comment.

## 3 Answers

Answer by Torsten

### Torsten (view profile)

on 21 Aug 2018
Accepted Answer

Use
for j = 1:length(Final_Latitude_Values)-1
instead of
for j = 1:length(Final_Latitude_Values)
Best wishes
Torsten.

#### 0 Comments

Sign in to comment. ### Fangjun Jiang (view profile)

Answer by Fangjun Jiang

### Fangjun Jiang (view profile)

on 21 Aug 2018

You have 8 locations thus 7 distances. When j is 8, Final_Latitude_Values(j+1) exceeds the matrix dimension.
Change the for-loop to
for j = 1:length(Final_Latitude_Values)-1

#### 0 Comments

Sign in to comment.

Answer by BOB

### BOB (view profile)

on 21 Aug 2018

Cheers folks! Works great.

Torsten

### Torsten (view profile)

on 21 Aug 2018
I don't know if this is intended, but note that you only calculate the distance between the last two components of the vectors, namely
[(Final_Latitude_Values(j)) (Final_Longitude_Values(j))]
and
[(Final_Latitude_Values(j+1)) (Final_Longitude_Values(j+1))]
for
j = length(Final_Latitude_Values)-1.

Sign in to comment.