Finding azimuths/bearings between many consecutive points in ArcGIS

Question

I have a ton of consecutive points and I need to know the bearing between each of them (a to b, b to c, c to d,etc). Ultimately, I will convert the numbers (bearings, azimuths?) to directions: N, NE, NNE, NNW,etc.

I have found a python script for use in the field calculator that comes close to doing this but it returns angles: https://geonet.esri.com/blogs/dan_patterson/2016/09/01/distance-calculations-using-the-field-calculator

Another option would be a script that can convert the angles returned by the above script to bearings/azimuths. For instance, the above script returns -90 rather than 270 for due west.

Answer 1

This will do it on a plane surface

import math
from itertools import cycle
def angle_wrt_x(B,A):
    ax, ay = A
    bx, by = B
    b = math.degrees(math.atan2(ax-bx,ay-by))
    if b < 0:
        b+=360
    elif b >= 360:
        b-=360
    return b

firstPoint = (0,0)
secondPoint = (1,1)

coord_pairs = [(0,0), (0,1), (1,1), (1,0)]

listcycle = cycle(coord_pairs)

for firstPoint in coord_pairs:
    secondPoint = listcycle.next()
    print firstPoint,secondPoint, angle_wrt_x(firstPoint,secondPoint)

Returns

(0, 0) (0, 1) 0.0
(0, 1) (1, 1) 90.0
(1, 1) (1, 0) 180.0
(1, 0) (0, 0) 270.0

Add this def, you'll need to finish it off for all other regions on the compass

def compassPoints(b):
    if b > 348.75 or b <= 11.25:
        compB = 'N'
    elif 11.25 < b <= 33.75:
        compB ='NNE'
    elif 33.75 < b <= 56.25:
        compB = 'NE'
    #continue this pattern for the rest of them....

   return compB

then call it with

for firstPoint in coord_pairs:
    secondPoint = listcycle.next()
    b = angle_wrt_x(firstPoint,secondPoint)
    print compassPoints(b)