gw.zi.light {lctools}

A light version of the Geographically Weighted Zero Inflated Poisson Regression (GWZIPR)

Description

This function allows for the calibration of a local model using the Geographically Weighted Zero Inflated Poisson Regression (GWZIPR) but reports and returns fewer results compared to the function gw.zi.

Usage

gw.zi.light(formula, family, dframe, bw, kernel, coords)

Arguments

formula

the local model to be fitted using the same syntax used in the zeroinfl function of the R package pscl. This is a sting (a symbolic description of the model) that is passed to the sub-models' zeroinfl function. For more details look at the details of the zeroinfl function.

family

a specification of the count model family to be used in the local model as in the zeroinfl function. Currently the only option tested is "poisson".

dframe

a numeric data frame of at least two suitable variables (one dependent and one independent)

bw

a positive number that may be an integer in the case of an "adaptive kernel" or a real in the case of a "fixed kernel". In the first case the integer denotes the number of nearest neighbours, whereas in the latter case the real number refers to the bandwidth (in meters if the coordinates provided are Cartesian). This argument can be also the result of a bandwidth selection algorithm such as those available in the function gw.zi.bw

kernel

the kernel to be used in the regression. Options are "adaptive" or "fixed". The weighting scheme used here is defined by the bi-square function (weight = (1-(ndist/H)^2)^2 for distances less than or equal to H, 0 otherwise)

coords

a numeric matrix or data frame of two columns giving the X,Y coordinates of the observations

Details

For more details look at the function gw.zi. gw.zi.light is only used by the function gw.zi.mc.test in order to asses if the local parameter estimates of the Geographically Weighted Zero Inflated Poisson Regression (GWZIPR) exhibit a significant spatial variation.

Value

ZI_LEst_count

a numeric data frame with the local intercepts and the local parameter estimates for each independent variable in the model's formula for the count part of the Zero Inflated model.

ZI_LEst_zero

a numeric data frame with the local intercepts and the local parameter estimates for each independent variable in the model's formula for the zero part of the Zero Inflated model.

Author(s)

Stamatis Kalogirou <[e-mail]>

References

Kalogirou, S. (2016) Destination Choice of Athenians: an application of geographically weighted versions of standard and zero inflated Poisson spatial interaction models, Geographical Analysis, 48(2),pp. 191-230. DOI: 10.1111/gean.12092 https://onlinelibrary.wiley.com/doi/abs/10.1111/gean.12092

See Also

gw.zi gw.zi.mc.test