How to draw a polyline of a certain distance?

Discussion created by jin87 on Feb 8, 2012
I have an existing polyline on the map. How do I get a point in any segment of the map and draw another polyline on top of the existing polyline using distance as an input, i.e. my web page would have an input field and iwill set the distance and choose the starting point of the existing polyline and by pressing a button, a new polyline will be place above the existing polyline.

could some one enlighten me? thank you very much