relationalClassFunction: Calculation of object relations to a class

In raff-k/Lslide: Functions for object-oriented image analysis in landslide science

Calculation of object relations to a class

Description

This function calculates statistics from neighbors of a given class to the given class (input is SpatialPolygonsDataFrame). Moreover, it is possible to calculate statistics for neighbors in a specific direction of a class object by setting the parameter for the getBoundingBox in the function call. In addition, if the neighbors are attributed to another second class, also a class-to-class relationship can be performed. Furthermore, attributing the first and the second class must not been necessarily hard coded, instead it is also possible to use expressions for the class-to-class relationship. However, here it can happen that some objects are assigned to both classes. As default, these objects are excluded from the statistic, but they can be included by setting the specific argument (class.as.neighbors). Moreover, the function is also capable to compute statistics on angle inputs by setting the function argument of var.is.angle to TRUE

Usage

relationalClassFunction(spdf, nb, class.var, class.var2 = NULL, var,
  var2 = NULL, var.is.angle = FALSE, class.as.neighbors = FALSE,
  only.neighbors = TRUE, centroid.for.distance = TRUE,
  calc.nb.flow = FALSE, col.flow = NULL, bb.intersection = "rgeos",
  return.bb.flow = FALSE, scale.factor.flow = c(1, 1), bb = NULL,
  centroid.flow = FALSE, set.centroid.flow = "inverse",
  k.centroid.flow = 2, k.flow = 2, scale.side.flow = "small",
  quiet = TRUE)

Arguments

spdf	SpatialPolygonsDataFrame, or full path of a shapefile
nb	object neighborhood based on poly2nb. Otherwise, neighborhood is computed by spdep::poly2nb(..., Queens = TRUE)
class.var	defination of class. Can be string or integer, or an expression in form of a list. For examples: class = as.integer(1), class = list("> 2.5", "expression"), class = list(c("> 2", "&", "< 7"), "expression")
class.var2	defination of a second class, see class.var. Enables class-to-class relationship. Default: NULL
var	vector with number or name defining 1. field of evaluation (i.e. slope) and 2. field of weights (i.e. area). For example: c("Slope", "Area") or c(1,2)
var.is.angle	variable for statistc represents angles. Other mathematical computation. Default: FALSE
class.as.neighbors	class object is also neighbor object. Default: FALSE
only.neighbors	object statistics are computed only for neighbors. Default: TRUE (FALSE means computation for the entiry data)
calc.nb.flow	include statistics for neighbors in flow direction. Default: FALSE
col.flow	column specifying direction. Default: NULL
bb.intersection	method for intersection with bounding box. Default: "rgeos" (alternative: "sp")
return.bb.flow	return geoemtry of counding box. Default: FALSE
bb	input of bounding box geometry. Default: NULL
quiet	no outputs in console. Default: TRUE
other...	see getBoundingBox

Value

data.frame containing object statistics, and optional the created geometry of getBoundingBox

Note

• object statistics to class according to ECOGNITION DEVELOPER (2014: 253-255, 375-381):

  • see relationalObjectFunction

  • ang_m_cl - mean angle of an object in relation to its surrounding class objects

  • ang_d_cl - mean difference angle of an object in relation to its surrounding class objects

  • ang_d_cl_a - absolute mean difference angle

  • bor_cl_a - absolute border of an object shared with neighboring objects of a defined class

  • bor_cl_rel - relative border of an object shared with neighboring objects of a defined class

  • dist_cl - distance of a not-neighbor object of a defined class to a defined class object

  • flow_nb_cl - object is located in flow direction (TRUE/FALSE)

• ECOGNITION DEVELOPER (2014) Reference Book. Trimble Documentation, München, Germany

• see getBoundingBox

• SpatialPolygonsDataFrame objects with NA values are ignored

• SpatialPolygonsDataFrame objects without neighbors are ignored

• SpatialPolygonsDataFrame input must have a valid Class and ID field. ID field must be contained of unique numbers

raff-k/Lslide documentation built on March 29, 2022, 6:52 p.m.