huff.updest: Huff Model market simulation with an updated destination
In MCI2: Market Area Models for Retail and Service Locations

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

Updating an existing location and (re-)calculating local market shares and total market areas of locations using the probabilistic market area model by Huff

1	huff.updest(huffmodel, dest.id, dest.attrac)

`huffmodel`	Object (`list`) created by the function `huff` (Huff Model)
`dest.id`	Code of the existing destination that has to be updated
`dest.attrac`	New attraction value of the existing destination

Updating the attraction value of an existing destination (e.g. store) in a given location system (Huff Model object). This function computes local market shares (p_{ij}) and total market areas (T_j) according to the Huff Model.

A huffmodel list (invisible) containing the following components:

`huffmat`	Huff interaction matrix (`data frame`), also containing the local market shares (`p_ij`)
`hufftotal`	Total location market areas (`data frame`), also containing the total market areas (`T_j`)
`params`	A `matrix` containing the user-defined weighting functions and the corresponding weighting parameters
`coords`	A `list` containing the coordinates and additional information of the origins (`coords_origins`) and the destinations (`coords_destinations`), inherited from the `tcmat` object
`tc.mode`	A `list` containing information about the transportation costs matrix, inherited from the `tcmat` object

The function is a wrapper of huff.shares and shares.total of the MCI package. For further information see the MCI documentation and the corresponding RJ paper (Wieland 2017).

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, tcmat.create

# 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

## 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)