How to return i,j locations for contor location

I use the contour command to return the position (lat and lon) of a specified contour depth i.e. 100m isobath.

[c1,h1] = contour(lon_rho,lat_rho,h,[100 100])

where lon_rho and lat_rho are matrices of lon and lat covering my region of interest and h is the bathymetry. These three matrices are all 542x770.

I can pull the lon and lat for the isobath of interest:

Mylon_100=c1(1,:)
Mylat_100=c1(2,:)

But what I want now it the i and j locations within my original matrices (542x770 grid) for each of the points along my contour line - preferably to a fraction of a grid cell.

i.e. maby a pont on the isobath has lat = 61.9 and lon= 175.3 and falls at grid point i=310.3 and j=645.8

Can anyone think of a smart way to get this information for each point along my isobath?

Thanks!

Answer 1

[Youssef Khmou]

hi ,

you can find the x/y coordinates of specified value in matrix : let s take a simple example:

 G=rand(542,770);
 G(400,333)=45; % example 
 [x,y]=find(G==45)

Does this helps a bit ?