Comments by emardini (Top 2 by date)

At first, determine which are the two closest points , if there is not clear which are the two closests points (by exemple, the distants are not very different) you must move your point. You can calculate the distance using the formula
distance = (xp - xn)^2 + (yp - yn)^2 for each 1 to n points in the ordered shape points (you do not need the square root). Finally you insert your point between the two closests points in the ordered points set.