Network distance to forest#

Algorithm ID: hedgetools:networkdistancetoforest

This tool calculates the distance between a hedge sub-network and the nearest forest (input layer). The tool first reconstructs the sub-networks. A sub-network is a cluster of connected arcs, so multiple arcs can belong to the same sub-network if they are connected.

Next, the distance is computed between each node of the hedges within the sub-networks and the forests. The distance results are recorded at the level of each node (as a new attribute), including the unique identifier of the nearest forest. In the arcs layer, a unique identifier of the sub-network to which each arc belongs is also recorded. The forest layer can be any polygon vector layer.

Parameters#

Label	Name	Type	Description
Input polygon layer	`INPUT_POLYGON`	[vector: polygon]	Polygon vector layer representing the hedges. Used to create connection points to forests, as hedge arcs may not necessarily intersect the forest polygons.
Input arc layer	`INPUT_ARC`	[vector: line]	Line vector layer representing the hedge median axis.
Input node layer	`INPUT_NODE`	[vector: point]	Point vector layer of hedge extremities.
Input forest layer	`INPUT_FOREST`	[vector: polygon]	Polygon vector layer representing forests.
Forest id field	`ID_FIELD`	[field: any]	Field containing the unique identifier of each forest polygon.
Spatial threshold (meters)	`THRESHOLD`	[numeric: double]	Distance threshold used to consider hedges without a physical connection as connected.
Override network construction from attributes	`OVERRIDE`	[boolean] Default: True	If toggled, will not use the `network_id` and `n_threshold` fields to build the network but the specified `Spatial threshold` value.
Output network distance layer	`OUTPUT_ARC`	[vector: line] Default: `[Create temporary layer]`	Output line vector layer.
Output network node layer	`OUTPUT_NODE`	[vector: point] Default: `[Create temporary layer]`	Output point vector layer.

Outputs#

Label	Name	Type	Description
Output network distance layer	`OUTPUT_ARC`	[vector: line]	Line vector layer with two new fields describing the nerworks : `network_id`: Unique identifier of the network. Hedges sharing the same ID belong to the same network. `n_threshold`: Distance threshold used to consider hedges without a physical connection as connected.
Output network node layer	`OUTPUT_NODE`	[vector: point]	Point vector layer with two new fields: `n_forest_id` (ID of closest forest) and `n_forest_dist` (distance to closest forest along the network).

Label

Name

Type

Description

Output network distance layer

OUTPUT_ARC

[vector: line]

Line vector layer with two new fields describing the nerworks :

network_id: Unique identifier of the network. Hedges sharing the same ID belong to the same network.
n_threshold: Distance threshold used to consider hedges without a physical connection as connected.

Output network node layer

OUTPUT_NODE

[vector: point]

Point vector layer with two new fields: n_forest_id (ID of closest forest) and n_forest_dist (distance to closest forest along the network).