huff.shares {MCI}

Huff model market share/market area simulations

Description

Calculating market areas/local market shares using the probabilistic market area model by Huff

Usage

huff.shares(huffdataset, origins, locations, attrac, dist, gamma = 1, lambda = -2, 
atype = "pow", dtype = "pow", gamma2 = NULL, lambda2 = NULL, check_df = TRUE)

Arguments

huffdataset

an interaction matrix which is a data.frame containing the origins, locations and the explanatory variables (attraction, transport costs)

origins

the column in the interaction matrix huffdataset containing the origins (e.g. ZIP codes)

locations

the column in the interaction matrix huffdataset containing the locations (e.g. store codes)

attrac

the column in the interaction matrix huffdataset containing the attraction variable (e.g. sales area)

dist

the column in the interaction matrix huffdataset containing the transport costs (e.g. travelling time or street distance)

gamma

a single numeric value of \gamma for the exponential weighting of the attraction variable (default: 1)

lambda

a single numeric value of \lambda for the (exponential) weighting of distance (transport costs, default: -2)

atype

Type of attraction weighting function: atype = "pow" (power function), atype = "exp" (exponential function) or atype = "logistic" (default: atype = "pow")

dtype

Type of distance weighting function: dtype = "pow" (power function), dtype = "exp" (exponential function) or dtype = "logistic" (default: dtype = "pow")

gamma2

if atype = "logistic" a second \gamma parameter is needed

lambda2

if dtype = "logistic" a second \lambda parameter is needed

check_df

logical argument that indicates if the given dataset is checked for correct input, only for internal use, should not be deselected (default: TRUE)

Details

This function computes the market shares from a given interaction matrix and given weighting parameters. The result matrix can be processed by the function shares.total() to calculate the total values (e.g. annual sales) and shares.

Value

Returns the input interaction matrix including the calculated shares (p_ij) as data.frame.

Author(s)

Thomas Wieland

References

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

See Also

huff.attrac, huff.fit, huff.decay

Examples

data(Freiburg1)
data(Freiburg2)
# Loads the data

huff.shares (Freiburg1, "district", "store", "salesarea", "distance")
# Standard weighting (power function with gamma=1 and lambda=-2)