1.1 Introduction to GIS
GISIn the strictest sense, a GIS system is a computer system capable of assembling, storing, manipulating and displaying geographically referenced information, i.e. data identified according to their locations. It is best tool that uses the power of the computer to pose and answer geographic questions [Edirisinghe et al, 2003]. Practitioners also regard the total GIS as including operating persons and the data that go into the system. GIS has been growing during the last few years in almost all different spatial applications. The GIS model is an integration of five basic components that are People, Software, Hardware, Procedures and Data [Padma Kumara et al, 2003]. Fig. 3.1 shows the GIS model with its components.
GISIn the strictest sense, a GIS system is a computer system capable of assembling, storing, manipulating and displaying geographically referenced information, i.e. data identified according to their locations. It is best tool that uses the power of the computer to pose and answer geographic questions [Edirisinghe et al, 2003]. Practitioners also regard the total GIS as including operating persons and the data that go into the system. GIS has been growing during the last few years in almost all different spatial applications. The GIS model is an integration of five basic components that are People, Software, Hardware, Procedures and Data [Padma Kumara et al, 2003]. Fig. 3.1 shows the GIS model with its components.
GIS software provides the functions and tools needed to store, analyze, and display information about places [Edirisinghe et al, 2003]. The key components of GIS software are;
# Tools for entering and manipulating geographic information. such as addresses or political boundaries
# Tools that create intelligent digital maps you can analyze, query for more information, or print for presentation
# An easy-to-use graphical user interface (GUI)
GIS careers typically include positions such as project manager, computer programmer, database administrator, system administrator, cartographic designer, business development, and related managerial and administrative roles. GIS has become such an important part of many organizations' information management strategy that it has resulted in the creation of a new position: Geographic Information Officer.
GIS has six fundamental operations in order to be useful for finding solutions to real world problems. Those are capturing data, storing data, querying data, analyzing data, displaying data and output data to hard copies.
The user guides the program to arrange and display data about places on the planet in a variety of ways- including maps, charts and tables. The hardware and software allows the users to see and interact with data in new ways by blending electronic maps and databases to generate color-coded displays. There are two types of data;
# Geographic, because data collected is associated with some location in space.
#Informational, because attributes, or the characteristics (data), about the space is what we want to learn about.
The database structure is very important part of database development. The overall database consists of spatial, temporal and attributes data. All database elements have spatial information and attribute data. But the few elements consist of temporal information. Fig. C.1 in Appendix C shows the outline of GIS database structure for the mail input layers. The spatial, temporal and attribute data related to each layer are given in Table C.1. Any geodetic coordinate system (eg. WGS 84) used in GPS converted to Everest 1830 geodetic coordinate system and after that projected with Transverse Mercator projection. The information presents in GIS database presents with the Transverse Mercator projection i.e. the formal projection system used in Sri Lanka. For the each and every layer required the good metadata system. The used software provides good metadata system. Fig. C.2 and Fig. C.3 shows the metadata relevant to the spatial information for Arc info coverage and shape files. It consists of all the data of map projection and scale. Fig. C.4a to Fig. C.4e shows the layers included in GIS database.
