OSM-Ship-Routing

OSM-Ship-Routing provides the backend of a ship routing service using OSM data. This repository implements the backend server for the interactive routing frontend. Moreover, it contains a component for merging OSM coastlines into closed polygons as well as a grid graph builder for the oceans.

Components:

• OSM-Ship-Routing server backend
• Grid Graph Builder
• Coastline Merger

Setup

Docker is the fastest way to deploy the OSM-Ship-Routing server backend on your system. The other components require a installation from source.

Docker

Pull the latest image from Dockerhub. Then run the backend server:

docker run -p 8081:8081 --name osm-server dmholtz:/osm-ship-routing:v2.0.2

A container with name osm-server is started and the routing service is exposed at port 8081.

Installation from Source

Prerequisites

• Go 1.18 or later

Merge Coastlines

Extracts coastline segments from a .pbf file and merges them to closed coastlines. The output (i.e. the list of polygons) is either written to the GeoJSON file or to a normal JSON file, which is less verbose than GeoJSON and which we call PolyJSON.

go mod tidy
go run cmd/merger/main.go

Graph Builder

Builds a spherical grid graph and implements the point-in-polygon test to check which grid points are in the ocean and will thus become nodes in the graph. Two types of grids are supported:

• Simple Grid
• Equidistributed Grid

The graph is written to a file in the .fmi format.

go mod tidy
go run cmd/graph-builder/main.go

OSM-Ship-Routing backend server

Starts a HTTP server at port 8081. By default, a grid graph with equidistributed nodes on the planet's surface, each having at most four outgoing edges is used. Routing is done by the BidirectionalArcFlagRouter from the graffiti project.

go mod tidy
go run cmd/server/main.go

Customization

The graph builder supports two grid types and can be customized as follows:

Simple Grid

Distributes nodes equally along the latidue and longitude axis.

Available Parameters:

• density: The overall number of grid points will be $2 \cdot density^2$.

Equidistributed Grid

Distributes nodes equally on the planets surface.

Available Parameters:

• nTarget: Number of points to distribute on the surface. The actual number of points may vary slightly.
• meshType: Defines the maximum number of outgoing edges per node. One can choose between four and six neighbors and default value is four neighbors.