The ORC Hex System

 

The ORC Partnership  www.orcpartnership.com

All the illustrations of this document are © ORC and Crown Copyright 2002 licence no 100038018. All rights reserved, and reproduced here with the authorization of the rights holder.

 

 Prepared by Jacques Paris under the guidance of Martin Hodder

(ORC Data Services Technical Director)

 

Objectives

 

The main objective was to establish a “permanent” geographic basis for collecting information and processing it.

 

The geographic definition of the “entities” (particularly their size) was to be able to detect local variations of the variables with a “reasonable” sensitivity given the main subject of inquiry.

 

Geographic coverage

 

“National” coverage, starting with United Kingdom

 

Main subject of inquiry

 

Retail market analysis.

 

Cellmap characteristics

 

A grid of uniform hexagonal geographic areas measuring 500 meters across.

 

The grid was created in MapInfo using Mapbasic and then clipped to the UK coastline again using MapInfo; there are 1.4 million hexagons (compared to 9300 postal sectors). It is held on a UK basis and it is in Native Mapinfo Format.

 

An example

 

In these maps, only areas with significant (in market analysis terms) data are shown in color.

 

1 – Postal sectors

Width of map is about 100Km

 

2 – Hexagonal geography

 

Following are different zooms of the same map with hex data, although the second only shows a subset of information

 

 

 

3 – data

 

Main origins of data

 

The expenditure data is from a government omnibus survey known as the Family Expenditure Survey (FES). Household locations come from ORC national Mapping Agency – Ordnance Survey. The product known as CodePoint gives the number of delivery points per postcode. ORC incorporates a Lifestyle Survey known as PRIZM and this is produced by Claritas. The location of retail outlets is captured by ORC in house data team.

 

Rules for data assignment to hex cells

 

Data is allocated by FES Region. This allows for different expenditure patterns in different parts of the country to be exposed. This is then assigned to the hex grid taking into account the number of households in each hex and the area of overlap between the FES regions and the hex grid. Finally a weighting is applied to each hex to reflect the household type by income contained therein. This information is taken from PRIZM and the actual weighted applied will depend on the product category. For instance, the weighting may be different for electrical goods when compared against clothing.

 

 

4 – main use

 

Main tools: ORC RSPM and SiteSelect

 

The RSPM (Retail Sales and Profit Model) is used to predict the sales of a town centre or an individual retail outlet, based on the availability of spend in the area and the competitions in the area and the drive time decay curve (that is how visits drop off the further from the store they are). This information is then used for working out the viability of a store or if you need more retailing in a town to stop money “leaking” out from the area.

 

SiteSelect will look at then money available and the “lack of competition” and the drive time decay curve to identify possible new sites for a particular retail outlet. This can be used as a first pass to see if locating a store in the area would be possible.

 

The Model is a combination of MapInfo / MapBasic and MS Access or SQL server depending on the size of the model with supplemented functionality using Visual Basic and Crystal Reports.

 

Output format and mapping

 

The output forecast is input directly into an Excel Spreadsheet where a profit and loss account can be generated, that is if a store model is being generated. All data that can be mapped is mapped. We have paper reports as well giving summaries of spend information, Census data and lifestyle information.

 

All mapping output is displayed with MI and there are automatic routines for producing images for reports and presentations. The main mapping output is a series of maps that define the catchment’s limits These limits are identified as Primary, Secondary and Tertiary catchment and identify where 50, 75 and 90% of the calculated spend actually comes from.

 

 

5 –output

 

 thematic hex geography

 

(from RSPM )

 

 

(from Site Select)

 

The surveyed area extends east/west between Swindon and Reading and north/south between Oxford and Newbury and shows where demand is high and supply is weak in electrical products. Hot spots are shown in red.

(zoom of the central area of previous map)

 

 

 

generated traffic flows

 

This should road traffic usage generated by a new centre. The idea is to show where possible pinch points may occur.

  

contour line presentation of catchments limits

 

Warrington: Primary, Secondary & Tertiary Catchments 2007

 

 

Applications with other hex definitions

 

Hex geography is also used with different cell sizes. For example:

 

A government sponsored study by CASA (Centre for Advanced Spatial Analysis) of Greater London abandoned postal sector or enumeration district boundaries as a measure of geography, choosing instead to use 200m squares instead”

 

“100 metre and 50 metre grids for LAPIS and for pub and nursing home catchments”

 

When using a different cell size (50m grids are very unlikely to be employed as they create massive data files), generally the data assignment is done from the start. It is not too surprising because using a different size simply reflects the different nature of the phenomenon to be treated, and thus of the required data. There has been no case of voluntary “refinement” of the grid for a given situation and the question of data “adaptation” from one grid size to the other has never come up.

The ORC Hex System