GIS All Over
by Evan H. Shu, FAIA
We are blown away by the amount of GIS data that is now available online. GIS, or Geographic Information System, data refers to a mapping database. Most people are now familiar with free mapping services such as Mapquest, Windows Live, or Google Earth, but GIS data goes well beyond that level of information.
You might well ask what the difference is between GIS and a regular map. GIS is basically a map combined with a database of information that can be overlaid on the map in layers as well as extracted as straight data. You can use it to do selective analysis of specific areas and help you make informed decisions. Think of GIS as a "smart" map that can show you a variety of information on a selected area.
For the architectural and construction professions, valuable GIS data might include topographical survey contours, defined wetland zones, Board of Assessor parcel boundaries, easement restrictions, utility lines, soil conditions etc. But this wealth of information might also extend to demographic and other information such as age of residents, household income, crime statistics and property value.
The amazing part is that most of this information is now viewable (or downloadable) online via government-maintained GIS databases. While we cannot attest that all locales are as well covered, we know that in the U.S., if you type in the name of your state along with "GIS," as in "Massachusetts GIS," you will easily find the links to your state GIS database (see list of other national and global GIS directories at the end of this article).
While the experience in using your own area's GIS data may differ, it may help to follow our own experience. We found our way to the www.massgis.com site, with a subsequent link to www.mass.gov/mgis.
Information can be viewed either via a standard browser like Internet Explorer, Netscape, or Mozilla Firefox, or else you can use their "Oliver" viewer (requires up-to-date Java installation) for more features and control of data layers.
We tried both and, in many ways, the online browser is a much easier way to go.
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Many interactive GIS web sites run a script or application within your web browser to provide basic interactivity.
Image: Courtesy City and County of Honolulu
Some municipalities offer downloads that allow integration of GIS information with Google Earth.
Image: Courtesy of Google; zoning underlay courtesy of City of Portland
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