GeoMinMOS {PracTools}

Check geographic PSUs to determine whether any are less than minimum measure of size threshold

Description

Identify geographic PSUs whose measure of size is below a specified minimum and combine those PSUs with others

Usage

   GeoMinMOS(lat, long, geo.var, MOS.var, MOS.min)

Arguments

lat

latitude variable in an input file. Must be in decimal format.

long

longitude variable in an input file. Must be in decimal format.

geo.var

Geographic variable ID for grouping

MOS.var

Measure of size (MOS) for each PSU

MOS.min

Minimum allowed MOS value

Details

GeoMinMOS is a utility function that should be run after using GeoDistMOS or GeoDistPSU. GeoMinMOS identifies each PSU whose measure of size, (MOS.var), is below the minimum specified by MOS.min. Distances to the latitude/longitude centroids of other PSUs are calculated. The undersized PSUs are then combined with the nearest PSUs in proximity order until the minimum MOS is met or exceeded. In some cases, this can result in the same input PSU being assigned to more than one combined PSU. Also, the distances between the centroids of the PSUs in a combination may be impractically large. Thus, the new combinations generated by GeoMinMOS should be treated as suggestions that should be manually reviewed and adjusted if desired.

Value

A list with four components:

Parameter.Information

A data frame with three elements: Minimum.MOS = value of MOS.min; Geo.vars.start = total number of PSUs in the input data set; Geo.Vars.lt.min.MOS = number of PSUs whose MOS was less than the minimum.

Input.Information

A data frame containing Geo.Var = geographic variable ID in the input data set used for grouping; Geo.MOS = MOS of each PSU in the input data set; Below.min.MOS = TRUE/FALSE indicator for whether a PSU's MOS was below the minimum in MOS.min.

Geo.var.MOS.output

A data frame with PSUs that were formed by combining undersized PSUs with adequately-sized PSUs. Columns in the data frame are: Geo.Var = new geographic variable ID for a combined PSU. This is equal to geo.var for the undersized PSU used in a combination; New.Geo.MOS = input MOS for each PSU; Geo.Cum.MOS = cumulative MOS for a combined PSU. The last PSU in a combination will have the total size of the combined PSU; Geo.Var.ID = geographic variable ID for a PSU in the input data set; Geo.Var.Num = sequential number (1, 2, etc.) for the PSUs in a combination; Geo.Var.Kms = distance in kilometers of a PSU's centroid to the centroid of the undersized PSU in a combination. The undersized PSU will have a distance of 0; Geo.Var.Miles = distance in miles of a PSU's centroid to the centroid of the undersized PSU in a combination. The undersized PSU will have a distance of 0; Geo.Var.Lat = latitude of the PSU centroid; Geo.Var.Long = longitude of the PSU centroid.

For.Review

A list of the geo.var's of PSUs that are used in more than one combination; these should be manually reviewed to determine which combination is preferred. The distances between PSU centroids in Geo.var.MOS.output can be helpful in the review.

Author(s)

George Zipf, Richard Valliant

See Also

GeoDistPSU, GeoDistMOS

Examples

library(PracTools)
library(dplyr)
g <- GeoDistPSU(Test_Data_US$lat,
                Test_Data_US$long,
                "miles",
                100,
                Input.ID = Test_Data_US$ID)
Test_Data_US <- inner_join(Test_Data_US, g$PSU.ID, by=c("ID" = "Input.file.ID"))
GeoMinMOS(lat      = Test_Data_US$lat,
          long     = Test_Data_US$long,
          geo.var  = Test_Data_US$psuID,
          MOS.var  = Test_Data_US$Amount,
          MOS.min  = 200000)