What is GIS?
GIS, or Geographic Information Systems, analyzes relationships between data and places in the world. When information is viewed on a map, it can be easier to understand. Trends and patterns become recognizable. GIS is a quickly growing industry as the importance of understanding geospatial patterns and relationships in data has become clear.
Data used in GIS includes any type of information that can be compared to its location. The data could be related to people, like demographics, income, education, or spending habits. If the purpose of the system is agricultural, the map could display land boundaries, topography, soil composition, and crop yields. To better understand a city, the map could have streets, parcel data, and points of interests, like businesses and restaurants. The location data used in GIS can be in the form of latitude and longitude, street address, or zip code, for example.
GIS combines data with geography. Each piece of information that is displayed on the screen comes from data files. The data is shown in layers which can be displayed or hidden as the GIS analyst wishes. For example, a community map could have layers for political boundaries, streets, bodies of water, parks, and points of interest. Layers can contain vector, raster, or web-based data. Vector data includes points, lines, and polygons and is useful for storing data that has discrete boundaries, such as country borders, land parcels, and streets. Raster data contains a matrix of pixels and is used for digital images like aerial imagery, floor plans, and topographic maps. Web-based data comes in a variety of forms, like near-real-time traffic and weather data. Care must be shown by the GIS analyst to display the layers in an appropriate order, as they sit on top of one another. Layers can be combined into overlays to improve the control over the layers and to help performance. The map projection will determine how the map appears, as the curved, three-dimensional earth must be mapped to a flat, 2D display.
GIS tools come in various forms. Maps can be displayed on desktop, web, and mobile devices. A GIS analyst could use a cell phone or tablet to input data in the field and then evaluate the results back at the office. Cities and counties now frequently compile GIS data like building plans, ordinances, and field research into a centralized database and offer interactive online maps to the public for free. Web map servers can store the GIS data and transmit it to users world-wide. Digital mapping saves the time and effort of drawing and handling paper maps. GPS devices can be integrated so they can be tracked in real-time.
Analyzing GIS data often leads to better decision making and cost savings. Salespeople are able to understand the demographics of customers in each zip code. Business can determine where to build a new store. Governments are empowered to understand their communities and plan for emergency response in the case of a natural disaster. Transportation companies can manage their fleets by integrating GPS tracking devices. Questions like, “How many school-aged children live within 1000 feet of a proposed elementary school?” and “Who should be notified about the approaching hurricane?” can be answered quickly and effectively. The uses of GIS are numerous and will continue to increase.
