mapXY This is an internal function that creates coords for chr. or arms or marks
mapXY(start, end, y, yMod, x, yfactor, r2, pts_1, pts_2, pts_3, pts_4)
1st index
last index
y coords
y coords modified because of squareness
x coords
y x factor
radius
points of squareness
points of squareness
points of squareness
points of squareness
number of edges in rounded vertices
list