As Gil Castle, founder and CEO of Castle Consulting in San Francisco, explains, "Anything that can appear on a map can be encoded into a computer and compared to anything on any other map, using longitude-latitude coordinates.

Spalding, a civil engineer, was smitten. In fact, he was so taken with the technology that he quit his job in the land development division of the engineering firm to start his own GIS consulting company, emGISt Inc. He's never looked back--and keeps pushing the technology forward.

Just recently, he transformed a GIS data blog he started in 2003 to Find GIS , a Florida-based GIS data resource site. The site includes GIS sources, GIS contacts, GIS data download sites and FTP sites for all 67 counties and 418 cities, towns and villages and links for the GIS divisions of multiple government agencies statewide.

Spalding says the site is designed to fill a need. "GIS Data and mapping applications are becoming crucial components within the real estate industry," he explains. One of the many questions I was continually asked by clients was where to find additional GIS data."

In addition to the Find GIS website, Spalding created and manages the Florida GIS Data Sharing Network, a community driven resource for users to list data sources, and the Florida GIS Data News Feed, which provides RSS feeds for his website.

Count Spalding among the growing legion of GIS aficionados—engineers, appraisers and any one of a number of other property-related professionals who are capitalizing on the power of the technology. GIS applications give all of them the tools to evaluate and analyze a broad list of key property-related questions. That list includes:

• Proximity to customers
• Location of potential competitors
• Crime rates
• Transportation infrastructure
• Regional labor pool characteristics
• Environmental risk factors, including flood plains and toxic sites

Castle says, "A CRE professional might ask a GIS to draw maps identifying all places throughout the nation where the number of households and their incomes exceed a certain threshold, if the number of competitors within a five-minute driving time is below a certain number, and that there are no environmental constraints within a one-mile ring."

When valuing a property, Castle explains, that same CRE pro could download all the recent transactions fulfilling certain criteria from a multiple-listing service; have the GIS automatically locate the comps on a street map, along with critical information such as the, date and cap rate of the most recent sale; point to each comp with the computer's arrow keys or mouse, display a photograph or even video of the comp; and statistically correlate the property-specific information to all the demographic, traffic, competitor, and environmental information displayed previously."

There's a lot to like about GIS, Spalding concurs. "I develop GIS applications to assist commercial real estate professionals, land brokers and developers identify any type of existing vacant land or any type of existing buildings in a given county or market area," he notes.

Spalding says typical applications include a digital outline of all properties with parcel control numbers, property ownership information, sales price, sales date, accessed taxes, roads, current zoning, future land use, FEMA flood zones, wetlands, census tracts, demographic data and countywide aerial images.

"The key is that multiple data sources from a variety of government agencies are combined into one searchable application," he adds. "Once you have all of the databases and layers tied into the GIS application, you can perform multiple queries or have the capability to analyze existing records/sales."

"Many companies set up a corporate entity for an individual land deal or large commercial building purchase, mainly for tax purposes. However, what they do not typically change is the mailing address of where the property tax bill is being sent," Spalding explains. With GIS, you can perform a dissolve of every mailing address in the county, which combines repetitive addresses into one record, and then perform any additional calculations you want, such as the acreage or sales price.

"You end up with a countywide digital map of the largest land holders within the county, which specifies and shows who owns X parcels of land, totaling X amount of acres," Spalding says. "GIS creates an easy way of tracking who owns what and who is purchasing what and where.

ESRI, a GIS and mapping software vendor, suggests that REITSs can gain a competitive edge over traditional investments by using GIS to quantify the investment potential of portfolios. "GIS technology makes it possible to show properties in the context of potential customers/tenants, nearness to competitors, inventories of like property, labor pools, and risk factors," the company states on its website.