Nodes

Nodes represent components and logical groupings in the P&ID graph.

Node Types

Node Type	Description	Examples
pid_component	Physical component on the drawing	Valve, Pump, Instrument, Reducer
piping_network_system	Logical grouping of related pipe segments	Cooling Water System, Steam System
piping_network_segment	A single tagged pipe run	2"-CW-001-A1A
instrumentation_loop	Control loop grouping instruments	FIC-101 loop

Node Structure

Every node has these fields:

{
  "tag": "FV-101",
  "id": "abc-123-def",
  "node_type": "pid_component",
  "node_classification": "piping_component.gate_valve",
  "orig_x": 150.5,
  "orig_y": 200.3,
  "orig_bbox_width": 50.0,
  "orig_bbox_height": 40.0,
  "attributes": [...]
}

Field	Description
tag	Human-readable identifier (e.g., "FV-101", "2-CW-001")
id	Unique system identifier
node_type	Category of node (see table above)
node_classification	Specific type in format entity_type.entity_class
orig_x, orig_y	Position on the original drawing
orig_bbox_width, orig_bbox_height	Size of the component bounding box
attributes	Additional properties (varies by component)

Node Classification

The node_classification field follows the format entity_type.entity_class:

Physical Components (pid_component)

Classification	Description
piping_component.gate_valve	Gate valve
piping_component.globe_valve	Globe valve
piping_component.ball_valve	Ball valve
piping_component.check_valve	Check valve
piping_component.reducer	Pipe reducer
piping_component.tee	Pipe tee
piping_component.elbow	Pipe elbow
instrument.transmitter	Transmitter
instrument.indicator	Indicator
equipment.pump	Pump
equipment.vessel	Vessel
reference.opc	Off-page connector

Logical Groupings

Node Type	Classification
piping_network_system	pns
piping_network_segment	pnsg
instrumentation_loop	loop

Attributes

The attributes array contains additional properties:

{
  "attributes": [
    {"name": "nominal_diameter", "value": "2", "data_type": "string"},
    {"name": "service_designation", "value": "CW", "data_type": "string"},
    {"name": "material_class", "value": "A1A", "data_type": "string"}
  ]
}

Common attributes vary by component type:

• Piping components: nominal_diameter, service_designation, material_class
• Instruments: measured_variable, function, loop_id
• Equipment: equipment_type, capacity

Querying Nodes

Get all physical components

{"query": ".pid_graph.nodes | filter(.node_type == \"pid_component\")"}

Get all valves

{"query": ".pid_graph.nodes | filter(contains(.node_classification, \"valve\"))"}

Get all pipe segments

{"query": ".pid_graph.nodes | filter(.node_type == \"piping_network_segment\")"}

Get nodes by tag pattern

{"query": ".pid_graph.nodes | filter(contains(.tag, \"FV-\"))"}