allToAllTraverse: All-to-all traversal

In alcyon: Spatial Network Analysis

All-to-all traversal

Description

Runs all-to-all traversal on a map with a graph. This is applicable to:

• PointMaps (Visibility Graph Analysis)

• Axial ShapeGraphs (Axial analysis)

• Segment ShapeGraphs (Segment analysis)

Usage

allToAllTraverse(
  map,
  traversalType,
  radii,
  radiusTraversalType,
  weightByAttribute = NULL,
  includeBetweenness = FALSE,
  quantizationWidth = NA,
  gatesOnly = FALSE,
  nthreads = 1L,
  copyMap = TRUE,
  verbose = FALSE,
  progress = FALSE
)

Arguments

map	A PointMap, Axial ShapeGraph or Segment ShapeGraph
traversalType	The traversal type. See TraversalType
radii	A list of radii
radiusTraversalType	The traversal type to keep track of whether the analysis is within the each radius limit. See TraversalType
weightByAttribute	The attribute to weigh the analysis with
includeBetweenness	Set to TRUE to also calculate betweenness (known as Choice in the Space Syntax domain)
quantizationWidth	Set this to use chunks of this width instead of continuous values for the cost of traversal. This is equivalent to the "tulip bins" for depthmapX's tulip analysis (1024 tulip bins = pi/1024 quantizationWidth). Only works for Segment ShapeGraphs
gatesOnly	Optional. Only calculate results at particular gate pixels. Only works for PointMaps
nthreads	Optional. Use more than one threads. 1 by default, set to 0 to use all available. Only available for PointMaps.
copyMap	Optional. Copy the internal sala map
verbose	Optional. Show more information of the process.
progress	Optional. Enable progress display

Value

A new map with the results included

Examples

# Pointmap analysis (VGA)
mifFile <- system.file(
    "extdata", "testdata", "simple",
    "simple_interior.mif",
    package = "alcyon"
  )
  sfMap <- st_read(mifFile,
    geometry_column = 1L, quiet = TRUE
  )
  pointMap <- makeVGAPointMap(
    sfMap,
    gridSize = 0.5,
    fillX = 3.0,
    fillY = 6.0,
    maxVisibility = NA,
    boundaryGraph = FALSE,
    verbose = FALSE
  )
allToAllTraverse(pointMap,
  traversalType = TraversalType$Angular,
  radii = -1L,
  radiusTraversalType = TraversalType$None
)

# Axial analysis
mifFile <- system.file(
    "extdata", "testdata", "barnsbury",
    "barnsbury_small_axial_original.mif",
    package = "alcyon"
  )
  sfMap <- st_read(mifFile,
    geometry_column = 1L, quiet = TRUE
  )
  shapeGraph <- as(sfMap, "AxialShapeGraph")
allToAllTraverse(
  shapeGraph,
  traversalType = TraversalType$Topological,
  radii = c("n", "3"),
  includeBetweenness = TRUE
)

# Segment analysis
mifFile <- system.file(
    "extdata", "testdata", "barnsbury",
    "barnsbury_small_segment_original.mif",
    package = "alcyon"
  )
  sfMap <- st_read(mifFile,
    geometry_column = 1L, quiet = TRUE
  )
  shapeGraph <- as(sfMap, "SegmentShapeGraph")
allToAllTraverse(
  shapeGraph,
  radii = c("n", "100"),
  radiusTraversalType = TraversalType$Metric,
  traversalType = TraversalType$Angular,
  weightByAttribute = "Segment Length",
  includeBetweenness = TRUE,
  quantizationWidth = pi / 1024L,
  verbose = FALSE,
  progress = FALSE
)

alcyon documentation built on April 3, 2025, 6:18 p.m.