oneToOneTraverse: One-to-one traversal

In alcyon: Spatial Network Analysis

One-to-one traversal

Description

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

• PointMaps (Visibility Graph Analysis)

• Segment ShapeGraphs (Segment analysis)

Usage

oneToOneTraverse(
  map,
  traversalType,
  fromX,
  fromY,
  toX,
  toY,
  quantizationWidth = NA,
  copyMap = TRUE,
  verbose = FALSE
)

Arguments

map	A PointMap or Segment ShapeGraph
traversalType	The traversal type. See TraversalType
fromX	X coordinate of the point(s) to start the traversal from
fromY	X coordinate of the point(s) to start the traversal from
toX	X coordinate of the point(s) to start the traversal from
toY	X coordinate of the point(s) to start the traversal from
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
copyMap	Optional. Copy the internal sala map
verbose	Optional. Show more information of the process.

Value

Returns a list with:

• completed: Whether the analysis completed

• newAttributes: The new attributes that were created during the process

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
  )
oneToOneTraverse(
  pointMap,
  traversalType = TraversalType$Metric,
  fromX = 7.52,
  fromY = 6.02,
  toX = 5.78,
  toY = 2.96
)

# 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")
oneToOneTraverse(
  shapeGraph,
  traversalType = TraversalType$Topological,
  fromX = 1217.1,
  fromY = -1977.3,
  toX = 1017.8,
  toY = -1699.3
)

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