Global to Local coordinate, Local to Global coordinate

Basic Concept

---

Base code

import numpy as np

def get_R(theta):
    """
    theta: [rad]
    """
    R = np.array([ [np.cos(theta), -np.sin(theta)], 
                   [np.sin(theta), np.cos(theta)] ])
    return R

pos = np.array([1, 0]).reshape(-1, 1)
heading_ang = 90 * (np.pi/180)  # [rad]

R = get_R(heading_ang)
inv_R = np.linalg.inv(R)

Global to local coordinate

# global to local
xy_local = np.dot(R, pos)
print(xy_local)  # [[0], [1]]

Local to global coordinate

# local to global
x_global = np.dot(inv_R, xy_local)
print(x_global)  # [[1], [0]]

and this is the inline code var just like this!