Geographic Information Systems (GIS) is an integration of hardware, software, data and people for the purpose of creating, manipulating, analyzing and displaying spatial data in order to facilitate the better understanding of geographic information. In contrast to time-series data, geospatial data are represented using a series of 2D measurements as longitudes and latitudes which implies that data is spatially distributed. GIS use thematic layers which are all connected by geography to collect and store data about real world. GIS allows its users to save a lot of cost as a result of higher efficiency in record keeping and thereby providing the ease of powerful decision making.
When representing spatial data in GIS, vector data and raster data are most commonly used. Vector data is co-ordinate based and implies that each object is represented using (X, Y) co-ordinates and other attribute information are also used in addition. Simply, a collection of points, lines and areas is called vector data and these are very useful for representing physical objects in a map. In a map, point are used to represent objects like school, bus-stop, hospitals etc. Roads, bridges, railway tracks etc. are represented with lines. Polygons are used to represent landscapes, cities, rivers etc. In general, smooth, rounded features are the vectors.
Raster data is represented in grid format in which all grids are of same size. Generally, raster data is produced by satellites and electronic devices which can be remote sensing data, satellite images or scanned pictures. In contrast to vector data, raster data doesn’t have database connected with each cell. Rasters are of 2 types as discreet and continuous. Gradually changing data like temperature and digital elevation models are represented using continuous rasters. Distinct themes or categories like land cover can be mapped using discrete raster’s.
GIS uses the following application using the spatial data they are described in detail below each of the application.
Urban and regional planning
It is one of the important areas in this arena where GIS is being used as a platform for planners to help in achieving their target of creating livable communities with improved quality of life while protecting environmental resources and enhancing economic development. In urban planning, a single map needs to contain many layers of details in which each layer contains different types of information and associated data.
Multi layered mapping which is a key feature in GIS facilitates this requirement. A GIS would be of immense help for a municipal planning committee to see variety of aspects like surface water, highly erodible lands, and high flood frequency and so on. Such multi layered capability impacts highly when developing an area. For an instance, a vector-based analysis and a raster-based analysis were carried out to identify the sites suitable for low-density residential development in Champaign and Urbana regions in Illinois with the aid of multiple criteria evaluation capability of GIS spatial planning support tools.
Highly accurate Route optimization algorithms can be built using GIS street network data that provides geography based time and distance allowing more realistic drive times, promising appointment times and accurate balancing of workloads. For instance, GIS route optimization was employed in Texas, USA for solving residential recyclables routing problem with the use of GIS software called ArcGIS along with ArcGIS Network Analyst. According to this research, GIS spatial relation of data was utilized during data processing stage. The GPS location of the truck along with the locations of the bins was linked using the join function build upon spatial location in order to determine the sequence that the bins are to be visited in a given route.
In an emergency situation, GIS facilitates all the government departments to share information on computer based maps via database in one location. The data required in the case of an emergency management is spatial data that can be placed on maps. All phases in the process of emergency management (planning, mitigation, preparedness, response and recovery) are heavily dependent on spatial data and other GIS facilities.