polylines match

Question

polylines match

nakulmandal opened this issue 5 years ago · comments

Hi,
what is the recommended way to find two polylines (intersecting each other) are in same direction.
Is there any function written for it?

David Symonds · Answer 1 · Fri Nov 01 2019 07:44:53 GMT+0800 (China Standard Time)

Can you be more specific?

nakulmandal · Answer 2 · Fri Nov 01 2019 15:38:33 GMT+0800 (China Standard Time)

Hi David,

I got two routes as polylines as lists of coordinates such as: [13.072624,52.333508,13.763972,52.679616] [52.679616,13.763972,52.333508,13.072624]

I need to compare the direction of two polylines. To do so I thought to get the angle between them and return true (going in the same direction) if it is smaller 45°.

example of route comparison==> https://i.stack.imgur.com/LDczR.png

How can I match two routes (means their direction are same or not)

David Symonds · Answer 3 · Tue Nov 05 2019 08:28:07 GMT+0800 (China Standard Time)

Note that a polyline is a sequence of edges, but your example is only a pair of vectors.

You can take the dot product of two vectors to get the angle between them. The r3.Vector type has a Dot method for that. See https://en.wikipedia.org/wiki/Dot_product for more detail.