Geographic Information Systems (GIS)

GIS was originally developed as an extension of the use and analysis of the traditional paper map. The most basic form of digital map data represents the same types of data that are displayed on paper maps. Digital maps use the same measurement frameworks, and frequently also use the same representation methods (e.g., colors, classification schemes) used on paper maps.

So why have a GIS instead of using paper maps? There are many reasons, of which these are but a few:

• GIS uses the analytical power of the computer to complete complex tasks which would be impossible or impractical using paper maps.
• GIS uses the computer's storage power to manage large datasets.
• GIS allows the integration of many different types of data from many different sources (maps, tabular data, aerial photos, elevation models, satellite imagery, CAD data, linear measurements, etc.) within an integrated storage, management, analysis, and display environment. Many of these data types are not easily represented on paper maps.
• GIS registers a variety of different data to the same coordinate space, which allows for the analysis of the combination of different layers (e.g., slope, forest windthrow hazard, distance to streams, and forest age). Frequently with paper maps, different thematic maps appear on different map sheets that are in different scales or use different representation frameworks.
• Digital data are more stable than paper media, easier to copy, and easier to distribute. Many websites exist that distribute digital geospatial data.
• Digitally created maps are more easily updated than paper maps (change the data and print a new copy).
• GIS makes it easy to reproduce maps. A single digital map file can be printed at will and multiple times. The same graphics file can be distributed over the net for users around the world.
• GIS allows the creation and use of "one-time" maps (whereas paper maps generally need to be printed and sold by the thousands to recapture the cost of production). For example, a map can be prepared with GIS specifically for a particular public presentation; the map may never be used after that presentation.
• GIS allows individual users to tailor their map displays for their own purposes, rather than having to settle for a general-purpose paper map.
• GIS eliminates some user bias in measurement or analytical processes (the computer repeats measurement and analytical processes identically, whereas people often repeat processes with random or systematic errors).
• GIS brings new tools for thinking differently about the world and its interrelationship.

What can GIS do?

The uses of GIS are just beginning to be explored. Although GIS has been put to great use up to the present, we expect to see an explosion in the use and application of GIS in the near and distant future. Here is another list of just a few of the things GIS can do:

• Locate geographic features based on their properties (e.g., "Where are all the cities within western Washington of population greater than 5000, but less than 10,000?").
• Identify properties of geographic features based on their location (e.g., "How many people live in the cities within 20 miles of Seattle?").
• Calculate the loss of timber volume &/or revenue due to riparian management zone buffers under current Forest and Fish Rules.
• Determine a good location of a Wal-Mart, based on the demographics and land-use/availability of the south Puget Sound area.
• Generate optimal routing and scheduling for a Sears appliance delivery and repair truck.
• Determine the ground area covered by a new cellular phone network. Locate "holes" in cellular coverage.
• Delineate watershed boundaries for the major tributaries of the Columbia River, and generate land-cover area statistics for those watersheds.
• Predict vegetation types for the Mt.Baker-Snoqualmie National Forest based on elevation, slope, and aspect.
• Predict landslide hazard for forest harvest units, based on slope, precipitation, and soil type.
• Create a relative-difficulty map for bicycle routes on the San Juan Islands.
• Locate "hot spots" for SIDS, and help determine if there is a relationship between SIDS and median income for households in the community of Onalaska, WA.
• Determine areas within Washington State in which exist a high abundance of vertebrate species, but whose wilderness protection status is low.
• Make colorful, interesting, and informative maps.