Citizens as Mobile Nodes of Environmental Collaborative Monitoring Networks. In Dynamic & Mobile GIS: Investigating Change in Space and Time
- C. Gouveia, A. Fonseca, B. Condessa, A. Câmara
Mobility is a contemporary requirement, and mobile users generate high demand on Geoinformatics, since more than 60% of the world’s population are subscribers to cellular networks. The positioning in mobility is of extreme importance to mobile user, he/she needs to know, store, and analyze their positions. The Geoinformatics inherited an ancient sexagesimal system for geographic position from Babylon civilization aged more than 4000 years based on degrees, minutes, and seconds. Babylonians used this sexagesimal system which base was 60 rather than 10 in the traditional decimal system. This is the reason of the division of one degree to 60 minutes, and one minute to 60 seconds. The realization of a point location by this ancient system has two formats, the first is composed from three different quantities which are degrees, minutes, and seconds, while the other is the decimal degree, which has the form of 2 digits before the decimal point and 8 digits after it. The use of this sexagesimal system for mobile user is not suitable as he/she requires a simple quantity that reflects the accuracy of navigator GPS. This paper analyses the complexity of the traditional sexagesimal system and its historical origin and limitations, and proposes a new modern metric system based on minutes to represent the geographic coordinates in a simple quantity and accepted accuracy for navigation purposes to be used in mobile GIS. Keyword: Mobile GIS; geographic metric; geographic minute; sexagesimal.