# Connectivity
<!-- <div class="algorithm-id">
<strong>Algorithm ID</strong>: <code>hedgetools:connectivity</code>
</div> -->
```{container} algorithm-id
**Algorithm ID**: `hedgetools:connectivity`
```

This tool compute connectivity metrics describing the hedge sub-network. 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.

## Parameters

| Label | Name | Type | Description |
|-------|------|------|-------------|
| 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 polygon layer | `INPUT_POLYGON` | [vector: polygon] <br> Optional | Polygon vector layer representing the hedges. |
| 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] <br> 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 connectivity layer | `OUTPUT` | [vector: line] <br> Default: `[Create temporary layer]` | Output line vector layer. |

## Outputs

| Label | Name | Type | Description |
|-------|------|------|-------------|
| Output connectivity layer | `OUTPUT` | [vector: line] | Line vector layer with two new fields describing the nerworks : <ul><li> `network_id`: Unique identifier of the network. Hedges sharing the same ID belong to the same network.</li><li>`n_threshold`: Distance threshold used to consider hedges without a physical connection as connected.</li></ul><br> And tne new fields of network metrics: <ul><li>`edges_count`: Number of links – number of edges within the network.</li><li>`nodes_count`: Number of nodes – number of vertices within the network.</li><li>`cyclomatic_number`: Cyclomatic number – number of cycles within the network.</li><li>`network_length`: Network length – total length of the network in meters.</li><li>`alpha_index`: Alpha index – proportion of existing cycles to the total possible number. Value ranges from 0 to 1.</li><li>`beta_index`: Beta index – average number of edges per vertex. Value ranges from 0 to 1.</li><li>`gamma_index`: Gamma index – proportion of network edges to the total possible number. Value ranges from 0 to 1.</li><li>`eta_index`: Eta index – average length of an edge.</li><li>`detour_index`: Detour index – proportion between the sum of Euclidean distances for each point pair and the actual network distance. Value ranges from 0 to 1.</li><li>`network_density`: Network density – network length divided by the area of its bounding box.</li></ul> |