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Graph-Based Maps

How warehouse topology is represented.


Graph Structure

A warehouse map is a weighted graph G = (V, E):

  • V: Set of nodes (vertices)
  • E: Set of edges connecting nodes
  • w: Edge weights (lengths)

Why Graphs?

Flexibility

  • Any layout can be represented
  • Non-rectangular warehouses
  • Multiple floors (separate graphs)

Efficiency

  • Standard graph algorithms
  • Fast pathfinding
  • Compact representation

Realism

  • Actual travel paths
  • Accurate distances
  • Physical constraints

Map Components

Nodes (Vertices)

{
  "id": 0,
  "name": "N0",
  "x": 0.0,
  "y": 0.0,
  "type": "aisle"
}

Properties:

  • Unique identifier
  • Position coordinates
  • Type classification

Edges

{
  "id": 0,
  "from": 0,
  "to": 1,
  "length": 3.0,
  "bidirectional": true
}

Properties:

  • Source and destination nodes
  • Physical length
  • Directionality

Map Topology

Connected Graph

All nodes must be reachable:

  • No isolated nodes
  • No disconnected regions
  • Robots can reach any location

Bidirectional vs One-Way

Bidirectional (default):

  • Robots can travel both directions
  • Most flexible

One-way:

  • Traffic flow control
  • Reduces congestion
  • More complex routing

Pathfinding

Shortest Path

Default routing finds shortest path by distance.

A* Algorithm

Uses heuristic for faster long-distance routing:

f(n) = g(n) + h(n)

Where:

  • g(n): Actual cost from start
  • h(n): Estimated cost to goal (Euclidean distance)

Congestion-Aware

Optional weighting by current congestion:

cost = distance + congestion_weight × congestion_score

Example Layouts

Simple Grid

5x5 grid with 3m spacing:

[N0]--[N1]--[N2]--[N3]--[N4]
 |     |     |     |     |
[N5]--[N6]--[N7]--[N8]--[N9]
 |     |     |     |     |
...

Zone-Based

Zone A          Zone B
[A1]--[A2]  |  [B1]--[B2]
 |     |    |   |     |
[A3]--[A4]--+--[B3]--[B4]
            |
        Main Aisle

Best Practices

Node Density

  • More nodes = finer granularity
  • Fewer nodes = simpler routing
  • Balance accuracy vs. complexity

Edge Lengths

  • Use actual physical distances
  • Consistent units (meters)
  • Account for corners/turns

Capacity Planning

  • Identify bottleneck paths
  • Add parallel routes if needed
  • Consider traffic flow