osmnx.consolidate_intersections incorrectly merges cloverleaf interchange loop ramps #1342
Description
Contributing guidelines
- I understand the contributing guidelines
Documentation
- My problem is not addressed by the documentation or examples
Existing issues
- My problem does not appear in an existing issue
What operating system and Python version are you using?
Windows11, python3.12
What OSMnx version are you using?
v2.0.1
Environment packages and versions
Package Version Editable project location
------------------------- -------------- ----------------------------------------------
absl-py 2.1.0
annotated-types 0.7.0
anyio 4.9.0
argon2-cffi 25.1.0
argon2-cffi-bindings 25.1.0
arrow 1.3.0
asttokens 3.0.0
astunparse 1.6.3
async-lru 2.0.5
attrs 25.3.0
babel 2.17.0
beautifulsoup4 4.13.4
black 24.10.0
bleach 6.2.0
branca 0.8.1
certifi 2024.12.14
cffi 1.17.1
charset-normalizer 3.4.1
click 8.1.8
coacd 1.0.5
colorama 0.4.6
comm 0.2.3
contourpy 1.3.1
cycler 0.12.1
dataclasses-json 0.6.7
debugpy 1.8.15
decorator 5.1.1
defusedxml 0.7.1
Deprecated 1.2.15
dill 0.3.9
et_xmlfile 2.0.0
etils 1.11.0
executing 2.2.0
fastjsonschema 2.21.1
filelock 3.16.1
flatbuffers 25.2.10
folium 0.20.0
fonttools 4.55.3
fqdn 1.5.1
freetype-py 2.5.1
fsspec 2024.12.0
gast 0.6.0
genesis-world 0.2.1 C:\Users\Luche\OneDrive\python project\Genesis
geographiclib 2.0
geopandas 1.1.1
geopy 2.4.1
glfw 2.8.0
google-pasta 0.2.0
grpcio 1.70.0
h11 0.16.0
h5py 3.14.0
httpcore 1.0.9
httpx 0.28.1
idna 3.10
imageio 2.37.0
imageio-ffmpeg 0.6.0
importlib_resources 6.5.2
ipykernel 6.30.0
ipython 9.4.0
ipython_pygments_lexers 1.1.1
isoduration 20.11.0
jedi 0.19.2
Jinja2 3.1.5
joblib 1.4.2
json5 0.12.0
jsonpointer 3.0.0
jsonschema 4.25.0
jsonschema-specifications 2025.4.1
jupyter_client 8.6.3
jupyter_core 5.8.1
jupyter-events 0.12.0
jupyter-lsp 2.2.6
jupyter_server 2.16.0
jupyter_server_terminals 0.5.3
jupyterlab 4.4.5
jupyterlab_pygments 0.3.0
jupyterlab_server 2.27.3
keras 3.10.0
kiwisolver 1.4.8
lark 1.2.2
lazy_loader 0.4
libclang 18.1.1
libigl 2.5.1
llvmlite 0.44.0
lxml 5.3.0
Markdown 3.7
markdown-it-py 3.0.0
MarkupSafe 3.0.2
marshmallow 3.25.1
matplotlib 3.10.0
matplotlib-inline 0.1.7
matplotlib-scalebar 0.9.0
mdurl 0.1.2
mistune 3.1.3
ml_dtypes 0.5.1
moviepy 2.1.2
mpmath 1.3.0
mujoco 3.2.5
mypy-extensions 1.0.0
namex 0.1.0
nbclient 0.10.2
nbconvert 7.16.6
nbformat 5.10.4
nest-asyncio 1.6.0
networkx 3.4.2
notebook 7.4.4
notebook_shim 0.2.4
numba 0.61.0
numpy 1.26.4
opencv-python 4.11.0.86
OpenEXR 3.3.2
openpyxl 3.1.5
opt_einsum 3.4.0
optree 0.16.0
osmnx 2.0.1
overrides 7.7.0
packaging 24.2
pandarallel 1.6.5
pandas 2.2.3
pandas-stubs 2.3.0.250703
pandocfilters 1.5.1
parso 0.8.4
pathspec 0.12.1
pillow 10.4.0
pip 25.2
platformdirs 4.3.6
plotly 5.24.1
pooch 1.8.2
proglog 0.1.10
prometheus_client 0.22.1
prompt_toolkit 3.0.51
protobuf 5.29.3
psutil 6.1.1
pure_eval 0.2.3
pycollada 0.8
pycparser 2.22
pydantic 2.7.1
pydantic_core 2.18.2
PyGEL3D 0.5.2
pyglet 2.1.1
pygltflib 1.16.0
Pygments 2.19.1
pymeshlab 2023.12.post2
pyogrio 0.10.0
PyOpenGL 3.1.9
pyparsing 3.2.1
pyproj 3.7.0
python-dateutil 2.9.0.post0
python-dotenv 1.0.1
python-json-logger 3.3.0
pytz 2024.2
pyvista 0.44.2
pywin32 311
pywinpty 2.0.15
PyYAML 6.0.2
pyzmq 27.0.0
referencing 0.36.2
requests 2.32.3
rfc3339-validator 0.1.4
rfc3986-validator 0.1.1
rfc3987-syntax 1.1.0
rich 13.9.4
rpds-py 0.26.0
scikit-image 0.25.0
scikit-learn 1.6.1
scipy 1.15.1
scipy-stubs 1.16.2.0
scooby 0.10.0
screeninfo 0.8.1
Send2Trash 1.8.3
setuptools 75.8.0
shapely 2.1.1
six 1.17.0
sniffio 1.3.1
soupsieve 2.7
stack-data 0.6.3
sympy 1.13.1
taichi 1.7.3
tenacity 9.0.0
tensorboard 2.19.0
tensorboard-data-server 0.7.2
tensorflow 2.19.0
termcolor 3.1.0
terminado 0.18.1
tetgen 0.6.4
threadpoolctl 3.5.0
tifffile 2025.1.10
tinycss2 1.4.0
torch 2.5.1
torchaudio 2.5.1
torchvision 0.20.1
tornado 6.5.1
tqdm 4.67.1
traitlets 5.14.3
types-python-dateutil 2.9.0.20250708
typing_extensions 4.12.2
typing-inspect 0.9.0
tzdata 2024.2
uri-template 1.3.0
urllib3 2.3.0
utm 0.8.1
vtk 9.3.1
wcwidth 0.2.13
webcolors 24.11.1
webencodings 0.5.1
websocket-client 1.8.0
Werkzeug 3.1.3
wheel 0.45.1
wrapt 1.17.2
xyzservices 2025.4.0
zipp 3.21.0How did you install OSMnx?
pip or uv (via PyPI)
Problem description
I used osmnx.consolidate_intersections to simplify a network with the default parameters, and it causes a merging error on cloverleaf interchanges.
By inspecting the source code, I found that “topologically close” nodes are defined as nodes that are in the same weakly connected component. However, the loop ramp of a cloverleaf interchange indeed satisfies this condition (the two endpoints of the loop ramp can be very close in position), which leads to the loop being merged incorrectly. This is very likely to happen when tolerance is set to a single scalar.
A simple solution I’m proposing is to add a new parameter to osmnx.consolidate_intersections, e.g., distance_tolerance, which accepts the same data types as tolerance. Its meaning is: if two endpoints are to be merged, they must also be very close along the path (network distance), not just satisfy Euclidean proximity and weak connectivity. I provide a simple modification of the source code to show how this new parameter could work (I hard-coded the new parameter as 50 here—this is only to illustrate the idea; the actual code may be more complex, since it might accept the same data types as tolerance):
The idea is to delete longer edges in the copied subgraph according to the new parameter to form finer subclusters (without needing to change tolerance). This can effectively avoid the cloverleaf interchange merging error when using the default parameters of osmnx.consolidate_intersections.
Minimal standalone reproducible example
import osmnx as ox
g = ox.graph_from_bbox((117.98,24.48,118.00,24.50))
g = ox.project_graph(g)
g = ox.consolidate_intersections(g)
ox.plot.plot_graph(g)