Abstract. A review is provided of some database and representation issues involved in the implementation of geographic information systems (GIS). The increasing popularity of web-based mapping systems such as Microsoft Virtual Earth and Google Earth and Maps, as well as other software offerings that are coupled with portable devices, such as the iPhone, has led to a proliferation of services that are characterized as being location-based. The data provided by these services is differentiated from other offerings by the presence of a locational component. In the past, this type of data was found primarily in geographic information systems (GIS). The available technology led to a focus on the paper map as the output device for responses. Since anything is better than drawing by hand, there was little emphasis on efficiency measures such as minimization of execution time. However, the emergence of of display devices has changed the mode of operation to one of expecting answers relatively...