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Last data update: 2014.03.03

R: Standard spatial contiguity matrixes

genW	R Documentation

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

# 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)