Create project from GMNS

In this example, we import a simple network in GMNS format. The source files of this network are publicly available in the GMNS GitHub repository itself.

References

• Importing from files in GMNS format

See also

Several functions, methods, classes and modules are used in this example:

• aequilibrae.project.Network.create_from_gmns()

# Imports
from uuid import uuid4
from os.path import join
from tempfile import gettempdir

from aequilibrae import Project
from aequilibrae.parameters import Parameters
import folium

# We load the example file from the GMNS GitHub repository
link_file = "https://raw.githubusercontent.com/zephyr-data-specs/GMNS/main/examples/Arlington_Signals/link.csv"
node_file = "https://raw.githubusercontent.com/zephyr-data-specs/GMNS/main/examples/Arlington_Signals/node.csv"
use_group_file = "https://raw.githubusercontent.com/zephyr-data-specs/GMNS/main/examples/Arlington_Signals/use_group.csv"

# We create the example project inside our temp folder
fldr = join(gettempdir(), uuid4().hex)

project = Project()
project.new(fldr)

No pre-existing parameter file exists for this project. Will use default
No pre-existing parameter file exists for this project. Will use default

In this cell, we modify the AequilibraE parameters.yml file so it contains additional fields to be read in the GMNS link and/or node tables. Remember to always keep the “required” key set to False, since we are adding a non-required field.

new_link_fields = {
    "bridge": {"description": "bridge flag", "type": "text", "required": False},
    "tunnel": {"description": "tunnel flag", "type": "text", "required": False},
}
new_node_fields = {
    "port": {"description": "port flag", "type": "text", "required": False},
    "hospital": {"description": "hospital flag", "type": "text", "required": False},
}

par = Parameters()
par.parameters["network"]["gmns"]["link"]["fields"].update(new_link_fields)
par.parameters["network"]["gmns"]["node"]["fields"].update(new_node_fields)
par.write_back()

As it is specified that the geometries are in the coordinate system EPSG:32619, which is different than the system supported by AequilibraE (EPSG:4326), we inform the srid in the method call:

project.network.create_from_gmns(
    link_file_path=link_file, node_file_path=node_file, use_group_path=use_group_file, srid=32619
)

Fields not imported from node table: wkt_coord. If you want them to be imported, please modify the parameters.yml file.

Now, let’s plot a map. This map can be compared with the images of the README.md file located in this example repository on GitHub: zephyr-data-specs/GMNS

links = project.network.links.data
nodes = project.network.nodes.data

map = links.explore(color="black", style_kwds={"weight": 2}, tool_tip="link_type", name="links")
map = nodes.explore(m=map, color="red", style_kwds={"radius": 5, "fillOpacity": 1.0}, name="nodes")

folium.LayerControl().add_to(map) # Add a layer control button to our map
map

Make this Notebook Trusted to load map: File -> Trust Notebook

project.close()

This project at /tmp/fb5b93f34fb1413392e7fc0ab376773d is already closed