Geographic Information Systems

A Geographic Information System (“GIS”) is a computer system capable of capturing, storing, analyzing, and displaying geographically referenced information; that is, data identified according to location. Technically, a GIS includes mapping software and its application with remote sensing, land surveying, aerial photography, mathematics, photogrammetry, geography, and tools that can be implemented with GIS software. In addition, a GIS can also be defined as the procedures, operating personnel, and spatial data that go into the system. However, a GIS typically doesn’t include all tools connected to topology.

The computer equipment used in GIS is like any other computer hardware such as keyboards, display monitors (screen), cables, Internet connection. In addition, the hardware configuration may include extra components such as large printers and plotters to make map output and devices to scan and input data from maps to GIS digitizers.

However, not every GIS needs this configuration, as the essential element is the type of information being stored. That is, a computer being used for GIS would include maps and images. In addition, GIS functions can be much more sophisticated such as to:
• measure distances, areas
• combine maps of the same area together
• keep inventories of what is where
• manage properties, facilities
• judge the suitability of areas for different purposes

The power of a GIS comes from the ability to relate different information in a spatial context and to reach a conclusion about this relationship. For example, most of the information we have about our world contains a location reference, placing that information at some point on the globe. In the strictest sense, the term “GIS” describes any information system that integrates stores, edits, analyzes, shares, and displays geographic information. In a more generic sense, GIS applications are tools that allow users to create interactive queries (user created searches), analyze spatial information, edit data, maps, and present the results of all these operations.

One of the most common products of a GIS is a map. Maps are generally easy to make using a GIS and they are often the most effective means of communicating the results of the GIS process. A GIS can also be used to emphasize the spatial relationships among the objects being mapped. While a computer-aided mapping system may represent a road simply as a line, a GIS may also recognize that road as the boundary between wetland and urban development between two census statistical areas.

Data capture—putting the information into the system—involves identifying the objects on the map, their absolute location on the Earth's surface, and their spatial relationships. Software tools that automatically extract features from satellite images or aerial photographs are gradually replacing what has traditionally been a time-consuming capture process. Objects are identified in a series of attribute tables—the "information" part of a GIS. Spatial relationships, such as whether features intersect or whether they are adjacent, are the key to all GIS-based analysis. As such, databases are extended to include GIS by using object oriented programming.

Thus, In terms of database design, GIS combine features of the relational model, with the object-oriented model and thus could be described as an “object-relational” system.
GIS technology can be used for scientific investigations, resource management, asset management, archaeology, environmental impact assessment, urban planning, cartography, criminology, geographic history, marketing, logistics, mapping and other purposes.

For example, when rainfall information is collected, it is important to know where the rainfall is located. This is done by using a location reference system, such as longitude and latitude, and perhaps elevation. Comparing the rainfall information with other information, such as the location of marshes across the landscape, may show that certain marshes receive little rainfall. This fact may indicate that these marshes are likely to dry up, and this inference can help us make the most appropriate decisions about how humans should interact with the marsh. A GIS, therefore, can reveal important new information that leads to better decision making.
In addition, GIS might allow emergency planners to easily calculate emergency response times in the event of a natural disaster, GIS might be used to find wetlands that need protection from pollution, or GIS can be used by a company to site a new business location to take advantage of a previously under-served market.

An active commercial GIS market (for example Autodesk is a major participant) has resulted in lower costs and continual improvements in the hardware and software components. These developments will, in turn, result in a much wider use of the technology throughout science, government, business, and industry, with applications including real estate, public health, crime mapping, national defense, sustainable development, natural resources, landscape architecture, archaeology, regional and community planning, transportation and logistics.

GIS is also appearing in location-based services (“LBS”). LBS allows GPS enabled mobile devices to display their location in relation to fixed assets (nearest restaurant, gas station, fire hydrant), mobile assets (friends, children, police car) or to relay their position back to a central server for display or other processing. These services continue to develop with the increased integration of GPS functionality with increasingly powerful mobile electronics (cell phones, PDAs, laptops. For example, web mapping services such as MapQuest utilize GIS.

GIS industry applications are diverse such as:
Utilities:
This category includes gas, phone, electric, water, cable TV companies. A single company may have hundreds of thousands of customer search with a connection to the network plus thousands of miles of wires, underground pipes with transformers, switches, poles...representing billions of dollars of installed infrastructure.   A utility company receives thousands of maintenance calls per day. As such, utilities need to:
• keep track of all this activity
• maintain accurate information about what is where
• keep records up to date
• make daily work assignments to crews
• provide information to others e.g. another company wishes to dig up a street, what do they need to avoid?

Transportation:
A commonly encountered GIS application are the information systems used by airlines and travel agents to make reservations, check in passengers, etc. In addition, a state department of transportation needs to:
• store information on the state of pavement everywhere on the state highway network
• maintain an inventory of all highway signs
• analyze data on accidents, look for 'black spots'

Also, a company could use GIS for enabling traveling salespeople to find locations and time-saving routes. Firms such as Federal Express, UPS, and government agencies such as the U.S. Postal Service use GIS to:
• keep track of shipments, know where they are
• plan efficient delivery routes

Agriculture:
Farmers increasingly use GIS to produce detailed maps and images for crop planting to:
• analyze yields
• plan efficient application of fertilizers, chemicals
These techniques are known as precision agriculture.

Foresters:
Use GIS to keep track of what timber is growing. They need to be able to plan timber harvest for how to provide for timber needs now, but maintain a healthy forest resource for the future. In addition, they use GIS to plan locations of roads, methods of cutting and removing logs to comply with environmental regulations. There is also a need to manage forests for many purposes, including recreation.

In summary, a GIS stores relational geographic information including maps and images. With rapid advances in technology and deceasing costs for storage and memory devices, the industry applications for GIS have grown in recent years from a small niche market. Similar to other relational databases, GIS enable users to perform interactive queries and its object oriented features aid in decision-making where data is linked to geography.