Set costs associated to edges based on geographic distances

The function setDistCosts sets the costs of a gGraph object using the geographic distance. The cost associated to an edge is defined as the great circle distance between the two nodes of this edge. setDistCosts actually relies on rdist.earth of the fields package.

Usage

setDistCosts(x, ...)

# S4 method for gGraph
setDistCosts(x, ...)

Arguments

x: a valid gGraph.
...: other arguments passed to other methods (currently unused).

Value

For the gGraph method, a gGraph object with appropriate weights. Note that former weights will be removed from the object.

Details

The notion of 'costs' in the context of gGraph objects is identical to the concept of 'weights' in graph (and thus graphNEL) objects. The larger it is for an edge, the less connectivity there is between the couple of concerned nodes.

Functions

setDistCosts(gGraph): Method for gGraph object

Examples


if (require(fields)) {
  ## load data
  plot(rawgraph.10k, reset = TRUE)
  geo.zoomin(list(x = c(110, 150), y = c(-10, -40)))
  plotEdges(rawgraph.10k)

  ## compute costs
  x <- rawgraph.10k[isInArea(rawgraph.10k)]
  x <- setDistCosts(x)

  ## replot edges
  plotEdges(x) # no big differences can be seen
  head(getCosts(x))
}
#> Loading required package: fields
#> Loading required package: spam
#> Spam version 2.10-0 (2023-10-23) is loaded.
#> Type 'help( Spam)' or 'demo( spam)' for a short introduction 
#> and overview of this package.
#> Help for individual functions is also obtained by adding the
#> suffix '.spam' to the function name, e.g. 'help( chol.spam)'.
#> 
#> Attaching package: ‘spam’
#> The following objects are masked from ‘package:base’:
#> 
#>     backsolve, forwardsolve
#> Loading required package: viridisLite
#> 
#> Try help(fields) to get started.


#> $`150`
#>    10038      151    10037      471 
#> 153.5122 135.5409 159.0169 159.0779 
#> 
#> $`151`
#>    10039      471      152      150    10038      472 
#> 152.7608 152.4379 136.0023 135.5409 159.8605 159.9643 
#> 
#> $`152`
#>    10040      472      153      151    10039      473 
#> 152.0093 151.6441 136.5697 136.0023 160.7123 160.8551 
#> 
#> $`153`
#>    10041      473      154      152    10040      474 
#> 151.2579 150.8388 137.2289 136.5697 161.5831 161.7623 
#> 
#> $`154`
#>    10042      474      155      153    10041      475 
#> 150.5036 150.0351 138.0768 137.2289 162.4662 162.6196 
#> 
#> $`155`
#>    10043      475      156      154    10042      476 
#> 149.6651 149.2157 138.9751 138.0768 163.3113 163.5481 
#>