Prevent Python For Loop from overwriting dictionary

I am trying to create a new dictionary (intersections) that contains intersecting areas from the polygons in a dictionary called zones.

intersections

zones

I use combinations to find all possible unique combinations of zones. Then I use Shapely's .intersects() to test if the zones intersect. If they do so, I would like their geometry being saved in variable int_geometry and then be stored in a dictionary (using: Shapely's .intersection()).

combinations

zones

.intersects()

if

int_geometry

.intersection()

I know there are four intersections, because this code returns them:

for a, b in combinations(zones.values(), 2):
a_geom = a['location']
b_geom = b['location']
if a_geom.intersects(b_geom) == True:
print a_geom.intersection(b_geom)


However, if I replace what comes after the if statement like in the code below, it starts overwriting itself.

if

intersections =

for a, b in combinations(zones.values(), 2):
a_geom = a['location']
b_geom = b['location']
if a_geom.intersects(b_geom) == True:
int_geometry = a_geom.intersection(b_geom)
int_area = round(int_geometry.area,2)
int_perimeter = round(int_geometry.length,2)
intersections =
'geometry' : int_geometry,
'attributes' :
'area' : int_area,
'perimeter' : int_perimeter,



pprint(intersections)


There are multiple topics on similar issues, though I cannot find my answer. I know I am overlooking something very obvious here, but I can't detect it. Can someone explain to me what I'm doing wrong?

intersections

for

intersections[geometry] = 'geometry' : int_geometry, 'attributes' : 'area' : int_area, 'perimeter' : int_perimeter,

1 Answer
1

index in int_index = "int_index " + str(index + 1) will always be the same value as after first loop it's value is constant. Hence data is being overwritten.

index

int_index = "int_index " + str(index + 1)

...

# PART 2 - ANALYSE THE DATA
intersections =
index = 0

for a, b in combinations(zones.values(), 2):
a_geom = a['location']
b_geom = b['location']
if a_geom.intersects(b_geom) == True:
int_index = "int_index " + str(index + 1)
int_geometry = a_geom.intersection(b_geom)
int_area = round((a_geom.intersection(b_geom).area),2)
int_perimeter = round((a_geom.intersection(b_geom).length),2)
intersections[int_index] =
'geometry' : int_geometry,
'attributes' :
'area' : int_area,
'perimeter' : int_perimeter,


index += 1

pprint(intersections)


zones

index

int_index = "int_index " + str(index + 1)

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