randomly sample a pair of values in a double

I have two doubles of the type coord_iso=65x2 double and coord_ce=65x2 double (they are all pairs of geographic coordinates).

I need to RANDOM sample one of the coordinate pairs inside the coord_iso. how can I do?

then with this randomly sampled pair and the first pair of coord_ce (row 1) I have to calculate the distance in km. in this case I was thinking of using distance and then the value/180*pi*6371.

you can help me?

Answer 1

[Star Strider]

‘I need to RANDOM sample one of the coordinate pairs inside the coord_iso. how can I do?’

One option —

RandomRow = randi(size(coord_iso,1));

RandomResult = coord_iso(RandomRow,:)

These can be combined into one assignment —

RandomResult = coord_iso(randi(size(coord_iso,1)),:)

Example —

coord_iso = [ 91.36  14.46 
              91.38  14.50 
              91.42  14.51 
              91.46  14.51 
              91.49  14.47];

RandomResult = coord_iso(randi(size(coord_iso,1)),:)

RandomResult = 1×2

91.3800 14.5000

.

Answer 2

[Jan]

You want a random integer in the range [1, 65] as index? randi([1, 65])

I have no idea, what "distance and then the value/180*pi*6371" means.

[ELISABETTA BILLOTTA]

for example, coord_iso (5x2 double)= 91,36 14,46

91,38 14,50

91,42 14,51

91,46 14,51

91,49 14,47

writing

a=coord_iso(randi(5,1))

I can randomly select a value in the first column. how do I then select the value of the second column corresponding to the one selected randomly in the first column?

for example in this case if a=91.38, how do I then select the 14.50 which is its equivalent but in the second column?

[Jan]

To select the complete row:

a = coord_iso(randi(5,1), :)