The effect of GIS data quality on infrastructure planning: School accessibility in the City of Tshwane, South Africa

Abstract

Worldwide geospatial datasets have become more readily available to non-expert users via the Internet and have changed the context in which spatial data is used. The quality of the available datasets can only be assessed if the corresponding metadata is available as well. The lack of metadata and non-expert knowledge of users often lead to the exploitation of data in different applications. In South Africa, the promulgation of the Spatial Data Infrastructure Act has created the environment for the capturing and sharing of spatial data and the publishing of metadata. The aim of this paper is to illustrate the financial cost involved when using poor quality data in planning for infrastructure such as schools. The positional accuracy of the quality of the dataset is evaluated by determining the locations of new schools using an original dataset and a verified dataset for primary and secondary public schools in the City of Tshwane. The result of the study is expressed in monetary terms and indicates that substantial amounts of money could be misspent if the necessary metadata to evaluate the quality of a dataset is not available. The study is not aimed at criticising the good work done by the Department of Basic Education but to illustrate the impact that data of insufficient quality may have on decision making.