- 4 minutes to read

System Landscape Diagram Example

The System Landscape diagram (L0) shows how multiple systems across an organisation relate to each other. It is the broadest view in the C4 hierarchy and a first-class diagram type in Nodinite — not a variant of L1 Context. Where an L1 focuses on one central system, an L0 Landscape covers all enterprise systems and their inter-dependencies.

See Example C4 Diagrams for an overview of all diagram types and when to use each.

When to Use

  • Enterprise architecture reviews and portfolio management
  • Identifying dependencies before a migration or reorganisation
  • Communicating the integration landscape to executives
  • Not a substitute for L1/L2/L3 — it does not zoom into any single system

Example: Order-to-Cash Enterprise Landscape

This example uses the Order-to-Cash (O2C) demo data. The four internal O2C systems (Portal, ERP, WMS, ERP-Finance) are shown alongside their supporting infrastructure and two external partner systems. This diagram exercises all shape types available at L0: Person, Person_Ext, System, System_Ext, SystemDb, SystemDb_Ext, SystemQueue, SystemQueue_Ext, and the BiRel bidirectional connector.

Preview Mermaid Code
C4Context title Order-to-Cash Enterprise System Landscape Person(customer, "Customer", "Places orders and receives confirmations") Person(warehouse_staff, "Warehouse Staff", "Confirms packing and delivery in WMS") Person_Ext(logistics_partner, "Logistics Partner", "External carrier managing last-mile delivery") Person_Ext(auditor, "External Auditor", "Reviews financial records and invoices") System(portal, "Portal", "Receives customer orders and delivers order confirmations") System(erp, "ERP", "Processes orders, schedules production, and manages planning") System(wms, "WMS", "Controls warehouse operations: packing and delivery") System(erp_finance, "ERP-Finance", "Generates invoices upon delivery confirmation") SystemDb(order_archive, "Order Archive DB", "Long-term storage of completed order records and audit trails") SystemQueue(integration_bus, "Integration Bus", "Internal message broker coordinating O2C events across systems") System_Ext(payment_gateway, "Payment Gateway", "Processes customer credit card payments") System_Ext(tax_authority, "Tax Authority Portal", "Receives and validates electronic invoice submissions") SystemDb_Ext(carrier_tracking, "Carrier Tracking DB", "External database providing real-time parcel tracking data") SystemQueue_Ext(edi_gateway, "EDI Gateway", "External B2B message queue exchanging order and invoice documents with trading partners") Rel_D(customer, portal, "Places orders", "JSON / HTTPS") Rel_D(portal, erp, "Forwards order for entry", "XML") Rel_Back(erp, portal, "Returns order confirmation", "CSV") Rel_D(erp, wms, "Triggers fulfilment and packing", "XML / JSON") Rel_D(wms, erp_finance, "Delivers confirmation for invoicing", "PSV / JSON") Rel(warehouse_staff, wms, "Manages packing and delivery", "Web") Rel(portal, integration_bus, "Publishes order events", "AMQP") Rel(erp, integration_bus, "Publishes planning events", "AMQP") Rel(erp_finance, order_archive, "Archives completed orders", "SQL") Rel(erp_finance, tax_authority, "Submits e-invoices", "REST API") Rel(logistics_partner, carrier_tracking, "Updates parcel status", "REST API") Rel(wms, carrier_tracking, "Reads delivery confirmation", "REST API") BiRel(erp_finance, edi_gateway, "Exchanges order and invoice EDI documents", "AS2") Rel(auditor, order_archive, "Reviews audit records", "Web") 
C4Context
    title Order-to-Cash Enterprise System Landscape

    Person(customer, "Customer", "Places orders and receives confirmations")
    Person(warehouse_staff, "Warehouse Staff", "Confirms packing and delivery in WMS")
    Person_Ext(logistics_partner, "Logistics Partner", "External carrier managing last-mile delivery")
    Person_Ext(auditor, "External Auditor", "Reviews financial records and invoices")

    System(portal, "Portal", "Receives customer orders and delivers order confirmations")
    System(erp, "ERP", "Processes orders, schedules production, and manages planning")
    System(wms, "WMS", "Controls warehouse operations: packing and delivery")
    System(erp_finance, "ERP-Finance", "Generates invoices upon delivery confirmation")
    SystemDb(order_archive, "Order Archive DB", "Long-term storage of completed order records and audit trails")
    SystemQueue(integration_bus, "Integration Bus", "Internal message broker coordinating O2C events across systems")

    System_Ext(payment_gateway, "Payment Gateway", "Processes customer credit card payments")
    System_Ext(tax_authority, "Tax Authority Portal", "Receives and validates electronic invoice submissions")
    SystemDb_Ext(carrier_tracking, "Carrier Tracking DB", "External database providing real-time parcel tracking data")
    SystemQueue_Ext(edi_gateway, "EDI Gateway", "External B2B message queue exchanging order and invoice documents with trading partners")

    Rel_D(customer, portal, "Places orders", "JSON / HTTPS")
    Rel_D(portal, erp, "Forwards order for entry", "XML")
    Rel_Back(erp, portal, "Returns order confirmation", "CSV")
    Rel_D(erp, wms, "Triggers fulfilment and packing", "XML / JSON")
    Rel_D(wms, erp_finance, "Delivers confirmation for invoicing", "PSV / JSON")
    Rel(warehouse_staff, wms, "Manages packing and delivery", "Web")
    Rel(portal, integration_bus, "Publishes order events", "AMQP")
    Rel(erp, integration_bus, "Publishes planning events", "AMQP")
    Rel(erp_finance, order_archive, "Archives completed orders", "SQL")
    Rel(erp_finance, tax_authority, "Submits e-invoices", "REST API")
    Rel(logistics_partner, carrier_tracking, "Updates parcel status", "REST API")
    Rel(wms, carrier_tracking, "Reads delivery confirmation", "REST API")
    BiRel(erp_finance, edi_gateway, "Exchanges order and invoice EDI documents", "AS2")
    Rel(auditor, order_archive, "Reviews audit records", "Web")

Shape Coverage

This example exercises the following L0 shape vocabulary from the toolbox plan:

Shape used Macro Notes
Person (internal) Person Customer, Warehouse Staff
Person (external) Person_Ext Logistics Partner, External Auditor
System (internal) System Portal, ERP, WMS, ERP-Finance
System (external) System_Ext Payment Gateway, Tax Authority Portal
Database System (internal) SystemDb Order Archive DB
Database System (external) SystemDb_Ext Carrier Tracking DB
Queue System (internal) SystemQueue Integration Bus
Queue System (external) SystemQueue_Ext EDI Gateway
Directional connector Down Rel_D Main O2C flow top-to-bottom
Reverse connector Rel_Back Confirmation returned without swapping FROM/TO
Bidirectional connector BiRel EDI two-way document exchange

Next Step

Zoom into one of the O2C systems with the L1: Context Diagram Example.