oneToOneTraverse {alcyon}

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
)