GMNSpy

Python tool for General Modeling Network Specification (GMNS) developed by Zephyr Foundation for Travel Analysis.

Installation

git clone https://github.com/e-lo/GMNSpy.git
cd GMNSpy
pip install .

Install Development Tools

pip install -r dev-requirements.txt

Usage

Read a single file

Returns a dataframe that conforms to the specified schema and have been validated.

df = gmnspy.in_out.read_gmns_csv(data_filename, schema_file=schemafilename)

Read a network

Returns a dictionary of dataframes that conform to the specified schema and have been validated.

Checks foreign keys between files.

net = gmnspy.in_out.read_gmns_network(data_directory, config: "gmns.spec.json")

GMNS specification

The GMNS specification is maintained in the /spec sub-directory as a series of JSON tables.

Data Table schemas

Data table schemas are specified in JSON and are compatible with the frictionless data table schema standards.

Example:

{
    "primaryKey": "segment_id",
    "missingValues": ["NaN",""],
    "fields": [
        {
            "name": "segment_id",
            "type": "any",
            "description": "Primary key.",
            "constraints": {
              "required": true,
              "unique": true
              }
        },
        {
            "name": "road_link_id",
            "type": "any",
            "description": "Required. Foreign key to road_links. The link that the segment is located on.",
            "foreign_key": "link.link_id",
            "constraints": {
              "required": true
              }
        },
        {
            "name": "ref_node_id",
            "type": "any",
            "description": "Required. Foreign key to node.",
            "foreign_key": "node.node_id",
            "constraints": {
              "required": true
              }
        },
        {
            "name": "start_lr",
            "type": "number",
            "description": "Required. Distance from ref_node_id.",
            "constraints": {
              "required": true,
              "minimum": 0
              }
        },
        {
            "name": "end_lr",
            "type": "number",
            "description": "Required. Distance from ref_node_id.",
            "constraints": {
              "required": true,
              "minimum": 0
              }
          }
    ]
}

Network Data Config

Network data schemas are specified in JSON and are compatible with the frictionless data data package standards.

Example:

{
  "profile": "gmns-data-package",
  "profile_version":0.0,
  "name": "my-dataset",
  "resources": [
   {
     "name":"link",
     "path": "link.csv",
     "schema": "link.schema.json",
     "required": true
   },
   {
     "name":"node",
     "path": "node.csv",
     "schema": "node.schema.json",
     "required": true
   }
 ]
}

Issues

Please add issues, bugs, and feature requests to Github.

Development

Current feature roadmap includes:

• conversion tools from open street map
• network connectivity checks
• auto documentation of schema to markdown files
• tests tests tests

Feel free to submit pull requests for consideration.

Credits

Author: Elizabeth Sall, UrbanLabs LLC