fsr (version 1.0.0)

fsr_components: Creation of a component

Description

There are two functions that build a component from coordinate pairs or a single sfg object labeled with a membership degree. This component can be added to a spatial plateau object. A component consists of an sfg object and an associated membership degree. A component can be built in two different ways. By using the function create_component, the component is formed by the means of a numeric vector, list or matrix that represents a pair of coordinates. By using the function component_from_sfg, the component is created from an sfg object.

Usage

create_component(raw_obj, md, type)
component_from_sfg(sfg, md)

Arguments

raw_obj

A vector, list or matrix containing the pairs of coordinates to create the sfg object of the component.

md

A numeric value indicating the membership degree of the component. It has to be a value in \(]0, 1]\).

type

A character value that indicates the type of the desired sfg object. It should be either "POINT", "LINE", or "REGION".

sfg

An sfg object. It should be either POINT, MULTIPOINT, LINESTRING, MULTILINESTRING, POLYGON or MULTIPOLYGON type. Other types of spatial objects are not allowed.

Value

A component object that can be added to a spatial plateau object (i.e., a pgeometry object).

Details

These functions create a component object, which is a pair of an sfg object and a membership degree in \(]0, 1]\).

The function create_component receives three parameters: raw_obj, md and type. The use of raw_obj is similar to the parameter of the family of functions of the sf package (st family) that creates spatial objects from a numeric vector, matrix or list (e.g., the functions st_point, st_multipoint, etc.). The spatial data type (i.e., the type of the sfg object) indicated by the parameter type represents simple and complex objects. For instance, "POINT" may refer to simple or complex point objects (internally, we can create a POINT or MULTIPOINT object).

The component_from_sfg builds a component object by using the specification of two parameters that directly represents the pair of an sfg object and its corresponding membership degree (i.e., md value).

Examples

# NOT RUN {
# Creating two components of the type POINT
v1 = rbind(c(1,2), c(3,4))
v2 = rbind(c(1,4), c(2,3),c(4,4))

md1 = 0.2
md2 = 0.1

comp1 <- create_component(v1, md1, type="POINT")
comp2 <- create_component(v2, md2, type="POINT")

# Creating two components of the type LINE

md3 = 0.45
md4 = 0.32

v3 = rbind(c(2,2), c(3,3))
v4 = rbind(c(1,1), c(3,2))

comp3 <- create_component(v3, md3, type="LINE")
comp4 <- create_component(v4, md4, type="LINE")

# Creating two components of the type REGION

p1 <- rbind(c(0,0), c(1,0), c(3,2), c(2,4), c(1,4), c(0,0))
p2 <- rbind(c(1,1), c(1,2), c(2,2), c(1,1))
list_pols_1 <- list(p1,p2)

p3 <- rbind(c(1,0), c(2,0), c(4,2), c(3,4), c(2,4), c(1,0))
p4 <- rbind(c(2,2), c(2,3), c(3,4), c(2,2))
list_pols_2 <- list(p3,p4)

comp_pol1 <- create_component(list_pols_1, 0.4, "REGION")
comp_pol2 <- create_component(list_pols_2, 0.6, "REGION")


# Creating components with an sfg object
library(sf)

# POINT
md1 <- 0.2
pts1 <- rbind(c(1, 2), c(3, 2))
comp1 <- component_from_sfg(st_multipoint(pts1), md1) 

# LINE
md2 <- 0.1
pts2 <- rbind(c(2, 2), c(3, 3))
comp2 <- component_from_sfg(st_linestring(pts2), md2) 

# REGION
md3 <- 0.4
matrix_object = matrix(c(1,1,8,1,8,8,1,8,1,1),ncol=2, byrow=TRUE)
pts3 = list(matrix_object)
comp3 = component_from_sfg(st_polygon(pts3), md3)

# }