Shipping an order from Madrid to Seville using GLEC methodology

An order does not always travel from A to B in a straight line. It may change vehicle, pass through a warehouse, or combine different transport modes. GLEC defines three levels to structure that journey.

How your shipment can travel

Madrid → Valencia (truck) → Valencia → Seville (another truck)

1. Movement ID (total shipment)

This is the entire journey of your goods from start to finish.

Madrid ──────────────────────────────→ Seville

Think of it like the “tracking number” you receive when you buy something online: it represents the whole trip.

2. Legs

These are the stages or intermediate stops of the journey.

Madrid → Valencia = Leg 1
Valencia → Seville = Leg 2

Each time the goods change vehicle, pass through a warehouse, or switch transport mode (from truck to ship, for example), it is a new leg.

3. Packages or units

These are the individual physical units being shipped.

If you send 5 boxes, you have 5 packages within that shipment.

What is the difference when measuring emissions?

Measurement level	What you get	When to use it
Total shipment	Full footprint of the journey	To give your customer the total emissions for their order
Legs	Footprint of each stage separately	To identify which part of the journey emits most (e.g., sea leg vs. road leg)
Packages or units	Footprint per individual unit	To assign emissions per package shipped to your customers

Why is it important to separate legs?

Each leg has its own tkm and emissions calculation, because it may use different vehicles or cover different distances.

Package: "Shipment #123"
   │
   ├── Leg 1 (Movement ID: M001)
   │   Madrid → Valencia (truck)
   │
   └── Leg 2 (Movement ID: M001)
       Valencia → Barcelona (train)

The package’s total emissions are the sum of emissions for each leg, applying the emission factor of the corresponding vehicle in each one.

Total tkm = (500 × 2) + (200 × 2) + (50 × 2) = 1,500 tkm

Emissions = Σ (tkm × factor for each vehicle)