from qgis.core import *
import math
@qgsfunction(args='auto', group='Custom')
def tekstretning_gon3(point_wkt, feature, parent):
"""
Calculate direction in gons from a POINT Z WKT string.
"""
try:
# Use the value directly (NOT feature[...])
point_str = point_wkt
# Remove WKT text
point_str = point_str.replace("POINT Z(", "").replace(")", "")
# Split coordinates
coords = point_str.split()
x = float(coords[0])
y = float(coords[1])
# Direction calculation
angle_radians = -math.atan2(y, x)
angle_degrees = math.degrees(angle_radians)
adjusted_degrees = angle_degrees + 180.0
result_gons = adjusted_degrees * 10.0 / 9.0
return result_gons
except Exception:
return None
QgsExpression.registerFunction(tekstretning_gon3) | 