# Minimum polygon angle

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1
07-08-2018 11:04 PM by
New Contributor III

I would like to have an information about the minimum angle in every polygon in my database. Is there a way to evaluate it automatically? I need this information to find polygons which have very sharp angles, which might indicate that those polygons have to be corrected. some example of the polygon which I am looking for is presented in the attached image.

Tags (6) by MVP Esteemed Contributor

If memory serves... but you will have to change the 'angle = np.sum ….' line to 'angle = np.min….'

``````import numpy as np
import arcpy
def angles_poly(a, inside=True, in_deg=True):
"""Sequential angles from a poly* shape
"""
a = a.getPart()
a =np.asarray([[i.X, i.Y] for j in a for i in j])
if len(a) < 2:
return None
elif len(a) == 2:  # **** check
ba = a - a
return np.arctan2(*ba[::-1])
else:
angles = []
if np.allclose(a, a[-1]):  # closed loop
a = a[:-1]
r = (-1,) + tuple(range(len(a))) + (0,)
else:
r = tuple(range(len(a)))
for i in range(len(r)-2):
p0, p1, p2 = a[r[i]], a[r[i+1]], a[r[i+2]]
ba = p1 - p0
bc = p1 - p2
cr = np.cross(ba, bc)
dt = np.dot(ba, bc)
ang = np.arctan2(np.linalg.norm(cr), dt)
angles.append(ang)
if in_deg:
angles = np.degrees(angles)
angle = np.sum(angles)  # ---- change to np.min
return angle
__esri_field_calculator_splitter__
angles_poly(!Shape!)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍``````

It is a '*.cal' file so the __esri_field_calculator_splitter__ line should split everything into the code block and expression line when you load it.

NOTE... haven't test this in a while 