Though most GIS users would probably identify with one approach more than another, they are not mutually exclusive. In addition to recognizing the many definitions of a GIS, it is also constructive to identify three general and overlapping approaches to understanding GISs-the application approach, the developer approach, and the science approach. In this regard, it is the people like you who are learning, applying, developing, and studying GISs in new and compelling ways that unifies it. There are probably just as many definitions of GISs as there are people who use GISs. Like several of the geographic concepts discussed previously, there is no single or universally accepted definition of a GIS. These are just a few definitions of a GIS. Online and mobile mapping, navigation, and location-based services are also personalizing and democratizing GISs by bringing maps and mapping to the masses. From the relatively simple task of mapping the path of a hurricane to the more complex task of determining the most efficient garbage collection routes in a city, a GIS is used across the public and private sectors. If the computer is situated on a network, the network can also be considered an integral component of the GIS because it enables us to share data and information that the GIS uses as inputs and creates as outputs.Īs a tool, a GIS permits us to maintain, analyze, and share a wealth of data and information. Each layer of the cake represents a different geographic theme, such as water features, buildings, and roads, and each layer is stacked one on top of another (see Figure 1.8 "A GIS as a Layered Cake").Īs hardware, a GIS consists of a computer, memory, storage devices, scanners, printers, global positioning system (GPS) units, and other physical components. One popular way to describe and to visualize a GIS is picturing it as a cake with many layers. GIS software keeps track of both the spatial and attribute data and permits us to link the two types of data together to create information and facilitate analysis. In addition to location, each of these objects also possesses certain traits of interest, or attributes The characteristics and qualities of features and phenomena located on the surface of the earth., such as a name, number of stories, depth, or population. ![]() refer to the real-world geographic objects of interest, such as streets, buildings, lakes, and countries, and their respective locations. Spatial data Facts about the location and position of phenomena on the earth’s surface. All GIS software, regardless of vendor, consists of a database management system that is capable of handling and integrating two types of data: spatial data and attribute data. There are also open-source GIS options, such as GRASS ( ), which is freely distributed and maintained by the open-source community. Though online mapping services and interfaces are provided by companies like Google, Yahoo!, and Microsoft, such services are not (yet) considered fully fledged GIS platforms. ( ), which distributes ArcGIS, and PitneyBowes ( ), which distributes MapInfo GIS. ![]() There are several GIS software providers, such as Environmental Systems Research Institute Inc. So what exactly is a GIS? Is it computer software? Is it a collection of computer hardware? Is it a service that is distributed and accessed via the Internet? Is it a tool? Is it a system? Is it a science? The answer to all these questions is, “GIS is all of the above-and more.”įrom a software perspective, a GIS consists of a special type of computer program capable of storing, editing, processing, and presenting geographic data and information as maps.
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