topic Re: Get XY coordinates of PLINE with arcs etc... in .NET Forum

Get XY coordinates of PLINE with arcs etc...

jholdawayUKBGN — Mon, 24 Aug 2020 14:15:22 GMT

How can I calculate the xy coordinates along a PLINE that has lines, arcs, etc...

In the attached screenshot, I would like to get an array of x,y coordinates along this PLINE that can contain any sort of line like arcs.

Any advice?

Re: Get XY coordinates of PLINE with arcs etc...

Jeff_M — Mon, 24 Aug 2020 21:23:34 GMT

That is what the GetPointAtParameter() method does. Each vertex is typically a whole number parameterso to get the point at the middle of the first arc (assuming the pline was created left to right):

var pt = oPline.GetPointAtParameter(3.5);

This returns a Point3d. Convert it to a Point2d if really needed.

Re: Get XY coordinates of PLINE with arcs etc...

jholdawayUKBGN — Tue, 25 Aug 2020 14:59:48 GMT

What is 3.5?

So if I wanted points along that arc how do I get that?

Re: Get XY coordinates of PLINE with arcs etc...

Jeff_M — Tue, 25 Aug 2020 18:09:57 GMT

The 3.5 is the midpoint between Parameter 3 and Parameter 4. The first vertex is Parameter 0. For any point along the first arc it will be 3.xxx where xxx is the percent along the arc to get the point.