huff.comp: Compare two Huff models
In MCI2: Market Area Models for Retail and Service Locations

Description Usage Arguments Value Author(s) References See Also Examples

Comparison of two existing Huff model objects with respect to changes in total market areas

1	huff.comp(huffmodel1, huffmodel2)

`huffmodel1`	Object (`list`) created by the function `huff` (Huff Model)
`huffmodel2`	Object (`list`) created by the function `huff` (Huff Model)

A data frame (invisible) with one row for each j destination and their total market area values from Huff model 1 and 2, respectively, and the corresponding total, share and percentage changes

Thomas Wieland

Huff, D. L. (1962): “Determination of Intra-Urban Retail Trade Areas”. Los Angeles : University of California.

Huff, D. L. (1963): “A Probabilistic Analysis of Shopping Center Trade Areas”. In: Land Economics, 39, 1, p. 81-90.

Huff, D. L. (1964): “Defining and Estimating a Trading Area”. In: Journal of Marketing, 28, 4, p. 34-38.

Loeffler, G. (1998): “Market areas - a methodological reflection on their boundaries”. In: GeoJournal, 45, 4, p. 265-272.

Wieland, T. (2015): “Nahversorgung im Kontext raumoekonomischer Entwicklungen im Lebensmitteleinzelhandel - Konzeption und Durchfuehrung einer GIS-gestuetzten Analyse der Strukturen des Lebensmitteleinzelhandels und der Nahversorgung in Freiburg im Breisgau”. Projektbericht. Goettingen : GOEDOC, Dokumenten- und Publikationsserver der Georg-August-Universitaet Goettingen. http://webdoc.sub.gwdg.de/pub/mon/2015/5-wieland.pdf.

Wieland, T. (2017): “Market Area Analysis for Retail and Service Locations with MCI”. In: The R Journal, 9, 1, p. 298-323. https://journal.r-project.org/archive/2017/RJ-2017-020/RJ-2017-020.pdf.

Wieland, T. (2018): “Competitive locations of grocery stores in the local supply context - The case of the urban district Freiburg-Haslach”. In: European Journal of Geography, 9, 3, p. 98-115.

huff, huff.newdest, huff.updest

# Compilation of tcmat list from existing datasets:
# (Results from the tcmat.create function)
data(Haslach_tcmatAirline)
# airline distances
data(Haslach_coords_origins)
# Coordinates of origins
data(Haslach_coords_destinations)
# Coordinates of destinationes

# Component "tc.mode":
Airline_tc.mode <- list()
Airline_tc.mode$tc.type = "airline"
Airline_tc.mode$tc.unit = "km"
Airline_tc.mode$tc.constant = 0

# tcmat with airline distances
# Compilation as a list:
tcmat_haslach_airline <- list(tcmat = Haslach_tcmatAirline,
coords_origins = Haslach_coords_origins,
coords_destinations = Haslach_coords_destinations,
tc.mode = Airline_tc.mode)

Drvtime_tc.mode <- list()
Drvtime_tc.mode$tc.type = "street"
Drvtime_tc.mode$tc.unit = "min"
Drvtime_tc.mode$tc.constant = 0

data(Haslach_tcmatDrvtime)
# car driving times

# tcmat with car driving times
# Compilation as a list:
tcmat_haslach_drvtime <- list(tcmat = Haslach_tcmatDrvtime,
coords_origins = Haslach_coords_origins,
coords_destinations = Haslach_coords_destinations,
tc.mode = Drvtime_tc.mode)

data(HaslachDistricts)
# IDs and information about customer origins
data(HaslachStores)
# IDs and information about destinations (grocery stores)

huffmodel1 <- huff (HaslachDistricts$WO, HaslachDistricts$WO_Einwohner, 
HaslachStores$LM, HaslachStores$LM_VKF, 
tcmat = tcmat_haslach_airline)
# Huff Model with standard parameters
# uses given transport costs matrix (tcmat_haslach_airline)

huffmodel1a <- huff (HaslachDistricts$WO, HaslachDistricts$WO_Einwohner, 
HaslachStores$LM, HaslachStores$LM_VKF, 
tcmat = tcmat_haslach_airline,
atype = "pow", gamma = 0.9, dtype = "pow", lambda = -2.1)
# Alternative weighting parameters

huff.comp(huffmodel1, huffmodel1a)
# Comparinf results of huffmodel1 and huffmodel1a

## Not run: 
huffmodel2 <- huff.newdest(huffmodel1, newdest.id = "LM_NEU",
newdest.addr = "Bettackerstrasse 3, Freiburg, Germany", 
newdest.attract = 1500)
# Adding a new destination with a given street address
# Recalculation of the Huff Model
# Needs internet access and accesses OpenStreetMap server(s)
# If server not available, the function will produce an error

## End(Not run)

huffmodel3 <- huff.updest (huffmodel1, dest.id = "LM01", 
dest.attrac = 1200)
# Update the attraction value of one grocery stores
# Recalculation of the Huff Model

## Not run: 
model.export(huffmodel3, "interactionmatrix", "totals")
# export as CSV files

## End(Not run)