chapter  34
Spatial Data Quality for GIS
ByHenri Aalders, Joel Morrison
Pages 14

Implementing today's changing technology means that fields such as cartography, photogrammetry and geodesy - which have traditionally been responsible for the collection and conveyance of spatial data and knowledge primarily through the making and use of maps - are in the process of switching from their historic (particularly the last 300 years) common end -product: a printed map on a flat sheet of paper, to a series of new products created from digital files containing data representing features on the earth. These disciplines are also facing, perhaps for the first time, a situation in which today's technology can and does enable the routine collection and use of data whose quality exceeds that which is needed for the map's purpose and/or that requested by the data user. In the digital mapping world data producers are collecting data and structuring spatial data into databases that contain topology, enhanced attribute information, and/or relationships amongst features. The fact that these digital databases may also be distributed allows other data producers to add attributes or relationships to features already in the database or to add new features. Therefore, any given data file may be the product of a number of data producers. The ease and speed in the collection of data results in many more datasets of various quality which duplicate earth features at different resolutions and which compete to satisfy the user's needs. These readily available distributed data files are accessible electronically at numerous isolated workstations.