CS) Informative Maps on PDA-phones
Chui Pui Ling Page 8 Ins, it was built to support the federal and provincial resource planning and management. The success in continent-wide analysis of complex data sets stimulated the development of various commercial mapping applications. Due to the
rapid growth of Internet ins, GIS was combined with Internet to introduce anew technology to handle spatial data on the Internet in 1996. By the end of the
20th century, users began to export the concept of viewing
GIS data over the Internet, requiring data format and transfer standards.
GIS represent real world objects in digital data with 2 methods, Raster and Vector. Raster datatype uses cells to store data and the value in each cell is either a discrete value or a null value. This kind of model requires lots of storage space to represent data yet allows easy implementation of overlay operations. On the other hand, vector datatype
uses geometries such as points, lines, or polygons to represent objects. It stores data only where necessary and the vector data can be displayed as vector graphics used on traditional maps. However, it is more difficult for implementation. Raster and vector data models treated the coverage as a gigantic field which can then be subdivided therefore they can be considered field models although they both referred to as layer models. Maps have traditionally been used to explore the Earth and to exploit its resources. GIS technology has enhanced the efficiency and analytic power of traditional mapping. Now, GIS technology is becoming an essential tool in the effort to understand the process of global change. Various map and satellite information sources can combine in modes that simulate the interactions of complex natural systems.
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