spfrontier (version 0.2.5)

genW: Standard spatial contiguity matrixes

Description

genW generates an spatial contiguity matrix (rook or queen)

rowStdrt standartizes spatial contiguity matrix by rows

constructW contructs a spatial contiguity matrix using object longitude and latitude coordinates

Usage

genW(n, type = "rook", seed = NULL)
rowStdrt(W)
constructW(coords, labels)

Arguments

n

a number of objects with spatial interaction to be arranged.See 'Details' for objects arranging principle

type

an optional type of spatial interaction. Currently 'rook' and ''queen' values are supported, to produce Rook and Queen Contiguity matrix. See references for more info. By default set to rook.

seed

an optional random number generator seed for random matrices

W

a spatial contiguity matrix to be standatised

coords

a matrix of two columns, where every row is a longitude-latitude pair of object coordinates

labels

a vector of object lables to mark rows and columns of the resulting contiguity matrix

Details

To generate spatial interaction between n objects the function arranges them on a chess board. A number of columns is calculated as a square root of n, rounded to the top. The last row contains empty cells, if n is not quadratic

The function divides every element in an argument matrix by the sum of elements in its row. Some spatial estimation requires this standartisation (generally - for faster calculations)

The function contructs a spatial contiguity matrix using object longitude and latitude coordinates. Eucledean distance is currently used.

References

Anselin, L. (1988). Spatial Econometrics: Methods and Models. Kluwer Academic Publishers, Dordrecht, The Netherlands.

Examples

# NOT RUN {
# Completely filled 10x10 rook contiguity matrix
rookW <- genW(100)
rookW

# Partly filled 10x10 rook contiguity matrix
rookW <- genW(90)
rookW

# Completely filled 10x10 queen contiguity matrix
queenW <- genW(100, type="queen")
queenW

# Completely filled 10x10 queen contiguity matrix
queenW <- genW(100, type="queen")
queenW

# Standartisation
stQueenW <- rowStdrt(queenW)
stQueenW


data(airports)

W <- constructW(cbind(airports$lon, airports$lat),airports$ICAO_code)

# }