Applying geographic information systems to delineate residential suburbs and summarise data based on individual parcel attributes

Background: Information aggregation to suburb level is of interest to engineers and urbanplanners. Readily available suburb boundaries do not always correspond to the suburb namesrecorded for individual properties in different data bases and unwanted errors are inherent.This mismatch of suburb names at different spatial scales poses a particular problem toanalysts. As part of a parallel research project into the development of a robust guideline forsuburb-based water demand analyses it was necessary to evaluate a large number of suburbsin terms of various attributes, one of which was the total suburb area.Objectives: Suburb boundaries were needed to assess the total suburb area. The objectiveof this research was to develop a novel geographic information system (GIS) application todelineate suburbs with boundaries corresponding to information contained in another database comprising individual property records. The suburb boundaries derived in this mannermay not relate to municipal boundaries, or sociopolitical boundaries, nor do they have to. Thefundamentally correct suburb boundary would be the one encompassing what is perceivedto be the suburb based on the suburb name in a particular data base that also contains otherinteresting attributes, such as water use, of individual properties.Method: The ArcGIS environment was used to delineate suburbs by means of triangulatedirregular network (TIN) modelling. Boundaries for suburbs with predominantly residentialland use were created that included all residential properties according to the suburb namefield as recorded in the treasury system. Other vacant areas were also included so as to obtainthe total suburb area. The methodology was developed to assist research in the field of potablewater services, but the method presented could be applied to other services that requiremanagement of information at suburb level.Results: This article illustrates how a tedious task of suburb delineation could be automatedin the GIS environment. The tool prevents subjective results that would be prone to error. Theautomated procedure described could effectively delineate a large number of predominantlyresidential suburbs in a relatively short time span and produce repeatable results. A reasonable outline could only be obtained if a sufficient number of parcels in the area contained the same suburb name. Functionality was added to the tool so that a limit could be set for this purpose. The default was that if more than 20% of the records were erroneous it was considered impractical to delineate a suburb. The derived suburb bou