I thought I already showed you in your duplicate question http://www.mathworks.com/matlabcentral/answers/115335#comment_195217. I don't know what gplot() is - I never use it. I showed you how you could use plot() to pass in a color. You just need to assign the color. For example
if distance > gvar(i)
plot(x,y, 'ro-'); % Plot red circles.
else
plot(x,y, 'bs-'); % Plot blue squares.
end
By the way, your loop over i and j is calculating all the distances twice, unlike how I showed you. The distance from point 1 to point 3 is the same as from point 3 to point 1 so why calculate it again?
