Creating sectors

Question

Hi all,

I have a set of lines that denote a direction of movement.  I would like to create 45 degree sectors that are centred on each line (i.e.) 22.5 degrees on either side of the existing line.  I've tried the distance and direction tool but not sure if it's the correct tool for the job or if I'm not using it correctly - any suggestions?

DavidMercer · Answer

Thanks!  I'll give this a try

danretired · Answer

Basic code

import numpy as np

def _arc_sector(radius=100, start=0, stop=1, step=0.1, xc=0.0, yc=0.0):
    """Create an arc from a specified radius, centre and start/stop angles

Requires:
    ---------
    `radius` : number
        cirle radius from which the arc is obtained
    `start`, `stop`, `step` : numbers
        angles in degrees
    `xc`, `yc` : number
        center coordinates in projected units

Returns:
    --------
      points on the arc
    """
    start, stop = sorted([start, stop])
    angle = np.deg2rad(np.arange(start, stop, step))
    x_s = radius*np.cos(angle)         # X values
    y_s = radius*np.sin(angle)         # Y values
    pnts = np.c_[x_s, y_s]
    cent = np.array([xc, yc])
    pnts = pnts + cent
    sector = np.concatenate((cent[None, :], pnts, cent[None, :]), axis=0)
    return sector

Sample to give you an idea

radius = 10.
x_c, y_c = 0., 0.

line_ang = 45.  # your line angle/direction...

start, stop = line_ang - 22.5, line_ang + 22.5  # start and stop relative to it

ar = _arc_sector(radius=10, start=start, stop=stop, step=2.0, xc=x_c, yc=y_c)