Revert a contracted graph created with dodgr_contract_graph back to a full, uncontracted version. This function is mostly used for the side effect of mapping any new columns inserted on to the contracted graph back on to the original graph, as demonstrated in the example.
Arguments
- graph
A contracted graph created from dodgr_contract_graph.
Details
Note that this function will generally not recover original graphs
submitted to dodgr_contract_graph. Specifically, the sequence
dodgr_contract_graph(graph) |> dodgr_uncontract_graph() will generally
produce a graph with fewer edges than the original. This is because graphs
may have multiple paths between a given pair of points. Contraction will
reduce these to the single path with the shortest weighted distance (or
time), and uncontraction will restore only that single edge with shortest
weighted distance, and not any original edges which may have had longer
weighted distances.
See also
Other modification:
dodgr_components(),
dodgr_contract_graph()
Examples
graph0 <- weight_streetnet (hampi)
nrow (graph0) # 6,813
#> [1] 6813
graph1 <- dodgr_contract_graph (graph0)
nrow (graph1) # 760
#> [1] 744
graph2 <- dodgr_uncontract_graph (graph1)
nrow (graph2) # 6,813
#> [1] 6813
# Insert new data on to the contracted graph and uncontract it:
graph1$new_col <- runif (nrow (graph1))
graph3 <- dodgr_uncontract_graph (graph1)
# graph3 is then the uncontracted graph which includes "new_col" as well
dim (graph0)
#> [1] 6813 16
dim (graph3)
#> [1] 6813 17