ssim_bandwidth {SSIMmap}

Bandwidth ranges for the SSIM Index for polygon maps.

Description

This function calculates the range of the bandwidth for the SSIM index using the square root of N and optimal trade-off between bias and variance.

Usage

ssim_bandwidth(
  shape,
  map1,
  map2,
  max_bandwidth = max_bandwidth,
  standardize = TRUE,
  option = "midpoint"
)

Arguments

shape

A sf polygon containing the attributes that can create polygon-based maps.

map1

The name of the first map to compare as a column in the shape.

map2

The name of the second map to compare as a column in the shape.

max_bandwidth

Maximum size of the bandwidth, and the maximum size needs to be larger than 12.

standardize

If TRUE, standardize the variables before computing the SSIM. Default is TRUE.

option

The option for selecting the range of the bandwidth derived from the optimal trade-off between bias and variance. Default is "midpoint."

Details

This function calculates the bandwidth range for the SSIM index for polygon maps using Gaussian kernel weighting. The bandwidth is calculated by two methods: 1) the square root of N and 2) the optimal trade-off between bias and variance. Users can select the bandwidth values from the range of the optimal trade-off, which minimize the trade-off between bias and variance, generated by two maps.

Value

A plot showing the bias/variance trade-off and the range of the optimal trade-off as vertical lines including the square root of N results as well. In addition, the console shows the results.

Examples

# Load example sf class object Toronto Area with attributes for maps:
# Pampalon Index,CIMD Index,
# and percentage of household commuting within the same Census Sub-Division of residence.
data("Toronto")

# Mapping two attributes
plot(Toronto$CIMD_SDD)
plot(Toronto$PP_SDD)

# Execution of bandwidth with maps above

ssim_bandwidth(Toronto,"CIMD_SDD","PP_SDD",max_bandwidth=100)