CODEWITHSUNDEEP
python
Munchkin
Munchkin

Reputation: 4946

different ways of triangle calculation

I have the (x,y)-coordinates of all three corners of a 2D-triangle. Now I want to check if a point with (xp,yp) is inside this triangle: I know two methods (only theoretically, not yet implemented) to check:

calculate the three linear equations of AB, AC, BC and check for each equation if P is left/right of it.

Problem 1: It must be accurate, because typical (x,y)-values of my corners and points look like this: (-0.049721957725789148, 0.024809768773549616) -> 18 positions after decimal point

Problem 2: It should has a good performance, because I want to check if P is inside triangle(ABC) OR inside triangle(DEF) OR inside triangle(GHI) OR inside triangle(JKL) OR outside of all of them. And I have to do it with ~ 10,000 points.

I read somewhere that the vector-way isn't that accurate. True? Do you know some other ways of checking? Which way of checking do you recommend?

Upvotes: 3

Views: 222

Answers (1)

Joop
Joop

Reputation: 8108

With problems like this always look for libraries... it is a mathematical problem and probably has a solution in a library. One quick answer:

import matplotlib
matplotlib.path.Path.contains_points   # is the function you are looking for

check the docstring for usage instructions.

Upvotes: 3

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