MATLAB: How to get the value of an element if it satisfies a logical condition

Question

Hello,

if I have two column vecotors, xcoord (that has some x-coordinates) and ycoord (that has some y-coordinates), How can I get the elements in xcoord and ycoord if it satisifes inpoly(xcoord,ycoord,#,*) ?

i.e. if inpoly(xcoord,ycoord,#,*) == 1 for all elements inside xcoord and ycoord.

where # and * are the coordinates of some polygon that I want to know which coordinates in xcoord and ycoord lies inside this polygon.

Thank you.

Answer 1

inpolygon gives you logical indices. From these you canget the points. Read about inpolygon and logical indexing.

idx = inpolygon(x,y,xv,yv) ;  % x, y are points and xv, yv are points which form a polygon
P = [x(idx) y(idx)]; % assuming x, y are column arrays