Multiple Routing on Seattle Road Network

The following is a complete example, using the Python API, of solving a graph created with Seattle road network data for a multiple routing problem via the /solve/graph endpoint. For more information on Graphs & Solvers, see Graphs & Solvers Concepts.

Prerequisites

The prerequisites for running the multiple routing solve graph example are listed below:

Graph server enabled
Python API
Solve graph script
Seattle road network CSV file

Python API Installation

Depending on the target operating system, a Python virtual environment may need to be installed first:

Python Virtual Environment

The native Kinetica Python API is accessible through the following means:

PyPI
Git

Python Virtual Environment

A Python virtual environment is necessary to install in an operating environment where Python is externally managed.

Install a Python virtual environment:
python3 -m venv .venv
Activate the Python virtual environment:
source .venv/bin/activate

PyPI

Install the API:
pip3 install gpudb
Test the installation:
python3 -c "import gpudb;print('Import Successful')"
If Import Successful is displayed, the API has been installed as is ready for use.

Git

In the desired directory, run the following, but be sure to replace <kinetica-version> with the name of the installed Kinetica version, e.g., v7.2:
git clone -b release/<kinetica-version> --single-branch https://github.com/kineticadb/kinetica-api-python.git
Change directory into the newly downloaded repository:
cd kinetica-api-python
In the root directory of the unzipped repository, install the Kinetica API:
sudo pip3 install .
Test the installation (Python3 is necessary for running the API example):
python3 examples/example.py

Data File

The example script references the road_weights.csv data file, mentioned in the Prerequisites, in the current local directory, by default. This directory can specified as a parameter when running the example script.

Script Detail

This example is going to demonstrate solving for the shortest possible route between destination points and a source point located in a Seattle road network.

Constants

Several constants are defined at the beginning of the script:

SCHEMA — the name of the schema in which the tables supporting the graph creation and match operations will be created
The schema is created during the table setup portion of the script because the schema must exist prior to creating the tables that will later support the graph creation and match operations.
TABLE_SRN — the name of the table into which the Seattle road network dataset is loaded
GRAPH_S — the Seattle road network graph
TABLE_GRAPH_S_MRSOLVED — the solved Seattle road network graph using the MULTIPLE_ROUTING solver type

Constant Definitions

SCHEMA = "graph_s_seattle_multi_route"
TABLE_SRN = SCHEMA + ".seattle_road_network"

GRAPH_S = SCHEMA + ".seattle_road_network_graph"
TABLE_GRAPH_S_MRSOLVED = GRAPH_S + "_multiple_routing_solved"

Graph Creation

One graph is used for the multiple routing solve graph example utilized in the script: seattle_road_network_graph, a graph based on the Seattle road network dataset (the CSV file mentioned in Prerequisites). The seattle_road_network_graph graph is created with the following characteristics:

It is directed because the roads in the graph have directionality (one-way and two-way roads)
It has no explicitly defined nodes because the example relies on implicit nodes attached to the defined edges
The edges are identified by WKTLINE, using WKT LINESTRINGs from the WKTLINE column of the seattle_road_network table. The road segments’ directionality (DIRECTION) is derived from the TwoWay column of the seattle_road_network table.
The weights (VALUESPECIFIED) are represented using the time taken to travel the segment found in the time column of the seattle_road_network table. The weights are matched to the edges using the same WKTLINE column as edges (EDGE_WKTLINE) and the same TwoWay column as the edge direction (EDGE_DIRECTION).
It has no inherent restrictions for any of the nodes or edges in the graph
It will be replaced with this instance of the graph if a graph of the same name exists (recreate)

Create Seattle Road Network Graph

create_s_graph_response = kinetica.create_graph(
    graph_name = GRAPH_S,
    directed_graph = True,
    nodes = [],
    edges = [
        TABLE_SRN + ".WKTLINE AS WKTLINE",
        TABLE_SRN + ".TwoWay AS DIRECTION"
    ],
    weights = [
        TABLE_SRN + ".WKTLINE AS EDGE_WKTLINE",
        TABLE_SRN + ".TwoWay AS EDGE_DIRECTION",
        TABLE_SRN + ".time AS VALUESPECIFIED"
    ],
    restrictions = [],
    options = {
        "recreate": "true"
    }
)