GIS Tools - Route Along Network

What Is Route Along a Network?

Route Along Network computes the shortest or fastest path between two points through a user-provided network of lines. Given an origin, a destination, and a network layer (roads, rivers, trails, pipelines, transit lines), the tool finds the sequence of network edges that connect them with the minimum total cost. Cost can be distance, travel time, or any numeric edge attribute. The operation is classical graph-based routing, the same technology that powers turn-by-turn driving directions, emergency dispatch, and supply chain optimization.

The Route Along Network tool on gis.tools performs network-based routing on any line layer you provide, directly in your browser. Drop in a road network (or any line layer that forms a connected graph), click two points to set origin and destination, and get the shortest path through the network. There is no upload, no geocoding, and no dependence on a third-party routing service. This matters for organizations that need to route on private networks (internal roads in a campus, mine haul roads, indoor pathways) where public routing services don't have data.

Routing on gis.tools uses standard graph algorithms (Dijkstra's, A*, bidirectional search) applied to a graph built from the line layer. The quality of the result depends entirely on the quality of the input network: it must be topologically connected, with lines meeting at shared vertices and no gaps.

How Network Routing Works

Build the graph: each line segment becomes an edge; endpoints and line intersections become nodes. The graph is built in memory from the input line layer.
Choose an edge weight: distance (length of each edge), travel time (length / speed), or any numeric attribute of the edge.
Snap origin and destination: the user-specified origin/destination points are snapped to the nearest graph node (or edge).
Run shortest path: Dijkstra's algorithm or A* finds the path with minimum total cost.
Reconstruct the route: the sequence of edges is extracted and returned as a LineString with the total cost.

Topology Requirements

Routing only works on a topologically clean network. Lines that visually appear to touch but don't actually share a vertex will produce a broken graph. Run the Topology Helpers tool first to snap endpoints and clean topology errors.

Direction and One-Way Handling

If edges in the network represent one-way streets, the tool can respect a direction attribute and route only in allowed directions.

Key Parameters and Options

Origin and Destination

Set by clicking on the map, typing coordinates, or selecting point features from a loaded layer.

Cost Field

Default is edge length in meters. Can be any numeric attribute (travel_time_seconds, toll_cost, elevation_gain).

Direction Field

Optional attribute that identifies one-way edges. Typically 0 = bidirectional, 1 = forward only, -1 = reverse only.

Algorithm

Dijkstra's guarantees the shortest path. A* is faster on large graphs when a heuristic is available.

Snap Tolerance

How close origin and destination must be to the network to snap successfully.

Practical Applications

Campus and Facility Routing

Universities, hospitals, and industrial parks have private road networks that public routers like Google Maps don't cover. Load your campus centerline layer into the route tool and provide internal directions.

Emergency Response Simulation

Fire and EMS dispatchers need to simulate response times under different station configurations. The route network tool lets them compute shortest paths on their actual road data, not an idealized public network.

Utility and Pipeline Operations

Water, gas, and electrical utilities route field crews on internal service networks that follow maintenance roads, easements, and private access routes.

Mining Haul Road Optimization

Open-pit mines use custom route networks on haul roads that change as the pit evolves. Routing on the current haul network identifies efficient cycle paths for dump trucks.

Hiking and Trail Planning

Outdoor recreation apps route on trail networks that aren't always in public routing services. Load the trail centerlines and offer turn-by-turn navigation.

Historical Route Analysis

Historians can route on digitized historical road networks to reconstruct travel times or trading routes in pre-modern eras.

Indoor Navigation

Airports, museums, and shopping malls use network routing on hallway centerlines to guide visitors.

Step-by-Step Workflow in gis.tools

Open the Route Along Network tool
Drag in your line network layer
Confirm topological cleanliness (fix with Topology Helpers if needed)
Click to set the origin point
Click to set the destination point
Pick a cost field (default is length)
Click "Compute Route"
Inspect the resulting path and total cost
Export the route as GeoJSON or KML

Worked Example

A mining engineer needs to compute the shortest haul road distance between Pit A and the primary crusher at Mine Site B. She loads the haul road centerline shapefile (500 edges) and runs the Topology Helpers tool to snap any loose endpoints. Then in the Route Along Network tool, she clicks the Pit A extraction point and the crusher point, picks "length_m" as the cost field, and clicks Compute. The result is a 3.2-kilometer path traced through 47 edges, exported as a GeoJSON for the operations dashboard.

Common Pitfalls and Gotchas

Disconnected network: the most common failure. If the graph is disconnected, the tool returns no route. Run Topology Helpers to fix gaps.
Missing edges in the source data leave the router unable to complete a path.
Wrong cost field: using raw length for a multi-speed network produces incorrect fastest paths.
One-way handling: without a direction field, the router treats every edge as bidirectional.
Very large networks (millions of edges) exhaust browser memory. Consider splitting into smaller tiles.
Snap failures: if origin or destination are far from any edge, routing fails.
Turn restrictions (no left turns, U-turns) are not modeled in simple graph routers; use a specialized engine like Valhalla for those.
Dynamic conditions (traffic, construction) require a real-time routing service, not a static network.

Tips for Best Results

Clean topology with Topology Helpers before routing
Reproject to a metric CRS for correct distance calculations
Include a direction attribute for one-way streets
Validate with a known route (start and end you already know the path for) before trusting new results
Pair with the Isochrone Generator for reach analysis on the same network

Comparison with Other GIS Approaches

QGIS offers Network Analysis tools under Processing. ArcGIS Pro has the Network Analyst extension with turn-by-turn support and advanced restrictions. PostGIS integrates with pgRouting for scalable database routing. Valhalla, OSRM, and GraphHopper are specialized open-source routing engines optimized for massive networks and turn restrictions. The browser-based gis.tools router is best for moderate-sized networks and quick interactive routing on custom data.

Performance Considerations

Dijkstra's algorithm is O((V + E) log V) and handles tens of thousands of edges comfortably in the browser. Very large networks benefit from A* with a good heuristic. Graph construction is often the slowest step.

Data Privacy and Browser-Based Processing

Private road networks (military bases, research campuses, industrial sites) never need to be uploaded. The router runs fully in your browser.

Related GIS Concepts

Dijkstra's algorithm is the classical shortest-path algorithm. A* is Dijkstra's with a heuristic to speed up goal-directed search. Isochrones extend shortest-path analysis into reach polygons at fixed cost thresholds. OD matrix computes all-pairs shortest paths between many origins and destinations. Graph topology is the data structure that makes routing possible.

Frequently Asked Questions

How do I route on my own network?

Load any line layer as the network, pick origin and destination, and click Compute.

Does the tool use public road data?

No — you provide the network. This is by design, so you can route on private or custom networks.

Can I get turn-by-turn directions?

The output is the path geometry with total cost. Turn-by-turn text requires additional logic beyond basic routing.

What if my network has errors?

Fix them with the Topology Helpers tool first. Routers require clean, connected graphs.

Does it support one-way streets?

Yes — include a direction attribute and specify it in the options.

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About Network Routing