gwr.lcr.cv: Cross-validation score for a specified bandwidth for GWR-LCR...
In GWmodel: Geographically-Weighted Models

gwr.lcr.cv

R Documentation

Cross-validation score for a specified bandwidth for GWR-LCR model

Description

This function finds the cross-validation score for a specified bandwidth for GWR-LCR. It can be used to construct the bandwidth function across all possible bandwidths and compared to that found automatically.

Usage

gwr.lcr.cv(bw,X,Y,locs,kernel="bisquare",
                    lambda=0,lambda.adjust=FALSE,cn.thresh=NA,
                    adaptive=FALSE, p=2, theta=0, longlat=F,dMat)

Arguments

`bw`	bandwidth used in the weighting function;fixed (distance) or adaptive bandwidth(number of nearest neighbours)
`X`	a numeric matrix of the independent data with an extra column of “ones” for the 1st column
`Y`	a column vector of the dependent data
`kernel`	function chosen as follows: gaussian: wgt = exp(-.5*(vdist/bw)^2); exponential: wgt = exp(-vdist/bw); bisquare: wgt = (1-(vdist/bw)^2)^2 if vdist < bw, wgt=0 otherwise; tricube: wgt = (1-(vdist/bw)^3)^3 if vdist < bw, wgt=0 otherwise; boxcar: wgt=1 if dist < bw, wgt=0 otherwise
`locs`	a two-column numeric array of observation coordinates
`lambda`	option for a globally-defined (constant) ridge parameter. Default is lambda=0, which gives a basic GWR fit
`lambda.adjust`	a locally-varying ridge parameter. Default FALSE, refers to: (i) a basic GWR without a local ridge adjustment (i.e. lambda=0, everywhere); or (ii) a penalised GWR with a global ridge adjustment (i.e. lambda is user-specified as some constant, other than 0 everywhere); if TRUE, use cn.tresh to set the maximum condition number. Here for locations with a condition number (for its local design matrix) above this user-specified threshold, a local ridge parameter is found
`cn.thresh`	maximum value for condition number, commonly set between 20 and 30
`adaptive`	if TRUE calculate an adaptive kernel where the bandwidth (bw) corresponds to the number of nearest neighbours (i.e. adaptive distance); default is FALSE, where a fixed kernel is found (bandwidth is a fixed distance)
`p`	the power of the Minkowski distance, default is 2, i.e. the Euclidean distance
`theta`	an angle in radians to rotate the coordinate system, default is 0
`longlat`	if TRUE, great circle distances will be calculated
`dMat`	a pre-specified distance matrix, it can be calculated by the function `gw.dist`