[tim_rutter]

Quick update, the performance issues I was getting were due to some poor test code! I was adding a lot more points than I thought. I have since got this working well using some "gluing code" i.e. not using binding as like you say that doesn't appear to work.

I have another question regarding the polylines. When I draw many lines close together there are times when they interfere with one another, i.e. cross the same points. When this happens it seems they render a different colour. I'm using a dark blue colour and where they interfere they seem to be a light blue. This would be ok except if there are enough interference points, they seem to dominate when zoomed out. The result of this is that if I plot a lot of graph lines close to each other and zoom out, the lines appear to be entirely in the new blue colour, something that is quite noticeable. Is this something someon can explain?