Run an igraph function on an sfnetwork object — wrap

Since sfnetwork objects inherit igraph objects, any igraph function can be called on a sfnetwork. However, if this function returns a network, it will be an igraph object rather than a sfnetwork object. With wrap_igraph, such a function will preserve the sfnetwork class, after checking if the network returned by igraph still has a valid spatial network structure.

Usage

wrap_igraph(.data, .f, ..., .force = FALSE, .message = TRUE)

Arguments

.data: An object of class sfnetwork.
.f: An function from the igraph package that accepts a graph as its first argument, and returns a graph.
...: Arguments passed on to .f.
.force: Should network validity checks be skipped? Defaults to FALSE, meaning that network validity checks are executed when returning the new network. These checks guarantee a valid spatial network structure. For the nodes, this means that they all should have POINT geometries. In the case of spatially explicit edges, it is also checked that all edges have LINESTRING geometries, nodes and edges have the same CRS and boundary points of edges match their corresponding node coordinates. These checks are important, but also time consuming. If you are already sure your input data meet the requirements, the checks are unnecessary and can be turned off to improve performance.
.message: Should informational messages (those messages that are neither warnings nor errors) be printed when constructing the network? Defaults to TRUE.

Value

An object of class sfnetwork.

Examples

oldpar = par(no.readonly = TRUE)
par(mar = c(1,1,1,1), mfrow = c(1,2))

net = as_sfnetwork(mozart, "delaunay", directed = FALSE)
mst = wrap_igraph(net, igraph::mst, .message = FALSE)
mst
#> # A sfnetwork: 17 nodes and 16 edges
#> #
#> # An unrooted tree with spatially explicit edges
#> #
#> # Dimension: XY
#> # Bounding box: xmin: 4548664 ymin: 2747309 xmax: 4549589 ymax: 2748537
#> # Projected CRS: ETRS89-extended / LAEA Europe
#> #
#> # Node data: 17 × 4 (active)
#>   name                  type     website                        geometry
#>   <chr>                 <chr>    <chr>                       <POINT [m]>
#> 1 Mozartkino            cinema   https://www.mozartki… (4549504 2747309)
#> 2 Haus für Mozart       theatre  NA                    (4549003 2747376)
#> 3 Mozartsteg/Rudolfskai bus_stop NA                    (4549589 2747507)
#> 4 Mozart Denkmal        artwork  NA                    (4549387 2747514)
#> 5 Mozartsteg/Rudolfskai bus_stop NA                    (4549491 2747551)
#> 6 Mozartsteg            bridge   NA                    (4549473 2747624)
#> # ℹ 11 more rows
#> #
#> # Edge data: 16 × 3
#>    from    to                           geometry
#>   <int> <int>                   <LINESTRING [m]>
#> 1     1     2 (4549504 2747309, 4549003 2747376)
#> 2     1     3 (4549504 2747309, 4549589 2747507)
#> 3     1     4 (4549504 2747309, 4549387 2747514)
#> # ℹ 13 more rows

plot(net)
plot(mst)


par(oldpar)