The South African standard for the exchange of digital geo-referenced information

Abstract

Geographically referenced (geo-referenced) information consists of all information that refers to the human-environment system and that can be localized in space and time. This includes cadastral, topographic, hydrographic and statistical information. The need for standards for the exchange of digital geo-referenced information is well known. The author was a member of the project team which drafted the South African standard and is a member of the committee charged with maintaining this standard. This paper will provide a technical overview of the South African standard for the exchange of digital geo-referenced information. It will describe briefly our concepts of geo-referenced information and the relational model used, which makes the standard easy to use and update. A set of data being exchanged consists of the File Identification (a fixed length, fixed format file that identifies the data), the Global Information Section (giving general details about the data being exchanged, such as reference surface and coordinate offsets used) and the Georeferenced Information elations (containing the data being exchanged). This paper will describe these components, specifying how they cater for information on data quality, classification, non-spatial attributes, alternate spatial attributes, vector and raster data.