Topology modifies source data

[mattijn]

Somehow there still modification of source data. Observe the following:

import topojson as tp
from geojson import Feature, Polygon, FeatureCollection

# prepare data
feat_1 = Feature(
    geometry=Polygon([[[0, 0], [1, 0], [1, 1], [0, 1], [0, 0]]]),
    properties={"name":"abc"}
)
feat_2 = Feature(
    geometry=Polygon([[[1, 0], [2, 0], [2, 1], [1, 1], [1, 0]]]),
    properties={"name":"def"}
)
fc = FeatureCollection([feat_1, feat_2])

# before Topology()
print('before')
print(fc['features'][0]['geometry'])

# apply Topology()
gdf = tp.Topology(fc)

# after Topology()
print('after')
print(fc['features'][0]['geometry'])

before
{"coordinates": [[[0, 0], [1, 0], [1, 1], [0, 1], [0, 0]]], "type": "Polygon"}
after
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-1-8fbba6233a22> in <module>
     22 # after Topology()
     23 print('after')
---> 24 print(fc['features'][0]['geometry'])

KeyError: 'geometry'