eco.bearing: Angular Spatial Weights

Description Usage Arguments Details Value Author(s) References Examples

Description

Construction of angular spatial weights

Usage

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eco.bearing(con, theta, XY = NULL, latlon = FALSE)

Arguments

con

an eco.weight or eco.lagweight object

theta

reference angle in degrees, between 0 and 180, counterclockwise, with 0 representing the positive x axis, 90 representing the positive y axis, 180 representing the negative x axis. Note that angles 0 and 180 yield identical results.

XY

Matrix/data frame with projected coordinates. Default NULL.

latlon

Are the coordinates in decimal degrees format? Defalut FALSE. If TRUE, the coordinates must be in the XY matrix/data frame with longitude in the first column and latitude in the second. The position is projected onto a plane in meters with the function geoXY.

Details

This program computes an angular weights object (AW) (or a list of AW). If a weights object is passed as argument ("con") the program computes an AW with this element. If XY is passed, the program first computes a matrix of N x N, where N is the number of rows in XY, and then uses the matrix as input to compute the AW. Each element in the weights matrices is then weighted by the squared cosine of the angle formed with the x positive axis by a line connecting the pair of points. Note that this method assumes that the distances in the eco.weight or eco.lagweight object are projected as great-circle distances (for example, using latlon = TRUE during weights construction or UTM coordinates for elements passed with "con", or latlon set TRUE in this function for a coordinates element passed with XY).

Note also that when angular weights are constructed for XY coordinates, the output consists of a weights object with values bounded between 0 and 1, being 1 if the if the direction pointed by the vector V connecting the elements i, j in the matrix points in the same direction of the reference vector R (with and angle theta with the positive x axis), and 0 if V is perpendicular to R.

Value

An object of class eco.weight with a bearing weights matrix

ACCESS TO THE SLOTS The content of the slots can be accessed with the corresponding accessors, using the generic notation of EcoGenetics (<ecoslot.> + <name of the slot> + <name of the object>). See help("EcoGenetics accessors") and the Examples for the function eco.weight and eco.lagweight.

Author(s)

Leandro Roser [email protected]

References

Rosenberg, M. 2000. The bearing correlogram: a new method of analyzing directional spatial autocorrelation. Geographical Analysis, 32: 267-278.

Examples

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## Not run: 

data(eco3)

"circle" method

con <- eco.weight(eco3[["XY"]], method = "circle", d1 = 0, d2 = 500)
bearing_con <- eco.bearing(con, 90)

W_list <- eco.lagweight(eco[["XY"]]) 
bearing_W_list <- eco.bearing(W_list, 90)


## End(Not run)

EcoGenetics documentation built on Jan. 14, 2018, 9:04 a.m.