[Python] PNG image to vector graphic conversion method with recognition of 1px lines?

I am trying to find a way to convert a .png image with 1px lines to a vector file. The issue I am having is that my approaches are very inconsistent due to the thin lines I am trying to recognize.

One idea was to use potrace, but I get very blobby results.

The other was to use OpenCV, with the result that OpenCV does not recognize all lines.

An example file I am trying to convert is this:

https://geoservices.bayern.de/od/wm...00,48.145000,11.565000&WIDTH=2048&HEIGHT=2048

Is there any other way to convert this to a vector file automatically?

i gave opencv another try and made it much further:

import sys
import cv2
import numpy as np
import svgwrite
import os

def raster_to_svg(input_path, output_path=None, simplify=False):
img = cv2.imread(input_path, cv2.IMREAD_GRAYSCALE)
if img is None:
print(f"Fehler: Bild konnte nicht geladen werden: {input_path}")
return

inv = cv2.bitwise_not(img)

_, thresh = cv2.threshold(inv, 127, 255, cv2.THRESH_BINARY)

contours, hierarchy = cv2.findContours(thresh, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)

height, width = img.shape
if not output_path:
output_path = os.path.splitext(input_path)[0] + "_white_areas.svg"
dwg = svgwrite.Drawing(output_path, size=(width, height))

for contour in contours:
if len(contour) < 3:
continue # Kein gültiges Polygon

points = [(int(p[0][0]), int(p[0][1])) for p in contour]

if simplify:
epsilon = 1.0 # Toleranz für Polygonvereinfachung
approx = cv2.approxPolyDP(contour, epsilon, True)
points = [(int(p[0][0]), int(p[0][1])) for p in approx]

dwg.add(dwg.polygon(points=points, fill='white', stroke='black', stroke_width=0.1))

dwg.save()
print(f"SVG gespeichert unter: {output_path}")

if __name__ == "__main__":
if len(sys.argv) < 2:
print("Verwendung: python raster_to_svg.py bild.png [output.svg]")
else:
input_file = sys.argv[1]
output_file = sys.argv[2] if len(sys.argv) > 2 else None
raster_to_svg(input_file, output_file)


but now i am struggling with the way pixels are represented: source:

result:

any idea how i could make these lines straight lines?

Thanks a lot!!

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