Creates an ss_tbl object of type "nwk" (SaTScan Network File).
A network file defines adjacency between locations as an edge list,
optionally with a distance or weight for each connection. SaTScan can use
this structure to define cluster expansion on a network (rather than by
Euclidean distance), making it suitable for road networks or other
connectivity-based proximity.
This constructor records which columns define the source location, the
neighbor location, and the optional distance/weight. It does not compute
distances or alter the network; those decisions are deferred to SaTScan
and the analysis configuration.
Usage
ss_nwk(data, loc_id, neighbor_id, distance = NULL, distance_units = NULL)
Arguments
- data
A data frame containing network edges.
- loc_id
Column name for the source location ID.
- neighbor_id
Column name for the connected neighbor ID.
- distance
Optional column name for distance/weight for the connection.
- distance_units
Units for distance (optional string).
Value
An ss_tbl object of type "nwk".
SaTScan File Specification
The Network File has the following structure:
<LocationID> <NeighborID> <Distance>
LocationID: Identifier for the source location.
NeighborID: Identifier for the connected neighbor location.
Distance: Optional. Numeric distance or weight between the two locations.