A data frame representing the flow between two points
or zones. The first two columns of this data frame should correspond
to the first column of the data in the zones. Thus in cents,
the first column is geo_code. This corresponds to the first two columns
of flow.
zones
A SpatialPolygonsDataFrame or SpatialPointsDataFrame
representing origins and destinations of travel flows.
Details
Origin-destination ('OD') flow data is often provided
in the form of 1 line per flow with zone codes of origin and destination
centroids. This can be tricky to plot and link-up with geographical data.
This function makes the task easier.
References
Rae, A. (2009). From spatial interaction data to spatial interaction information?
Geovisualisation and spatial structures of migration from the 2001 UK census.
Computers, Environment and Urban Systems, 33(3). doi:10.1016/j.compenvurbsys.2009.01.007