GIS: Uses and Integration Possibilities

Jim Simmons, Research Fellow

GIS (Geographical Information System) is the revolutionary technology behind the navigation devices for cars and precision guided military ordnance. In our profession, it has been largely confined to a select group of commercial appraisers and corporate decision makers. I'm exploring the idea of bringing GIS driven data to the residential appraiser's desktop.

We want to look at ways to develop and test a new GIS based data platform by which many geographically related assets can be seamlessly accessed and automatically entered into our WinTOTAL forms software. What this means to appraisers is simple: less time spent gathering and entering essential information into a report, combined with a greater degree of accuracy and consistency.

If successful, an "open GIS portal" and published set of interface guidelines could bring a list of Web based data services to the mainstream appraisal community. Eventually both fee based vendor services and freely available governmental services may be accessed just by the appraiser selecting controls from a toolbox related to the needed data.

Once installed, the software would either feature the ability to select a subject property from zooming in on a map defined by parcels and/or from a lookup list or search field by, say, address or parcel number in the appraiser's service area. When confirmed, the coordinates would be sent to the relevant servers to return the current information needed. The appropriate data is then pre–entered in the proper fields ready for review with no additional key entry.

I think many appraisers will like the powerful and rich GIS environment since many aspects of geographical information are more visual, and intuitive, than their text–based relatives. Given time and development, the next phases may include:

1. Defining neighborhoods by drawing outlines on maps


2. Selecting/deselecting comparables by geographical features/filters like distance to railroad tracks, busy streets, zoning or those in favored school districts in addition to the typical size, age, date of sale attributes;


3. GIS coded photo or mapping utilities

As appraisers are asked to address more hypothetical problems they will need more powerful tools as a result, and certainly GIS and its components contain plenty of horsepower.

One of the most useful aspects of GIS is its ability to create maps. Adjusting the format and labeling functions of maps can produce results from basic street lines to complex interactive cartographic masterpieces. The only limitation will be the appraiser's desires and needs.

Real estate appraisal by nature is location oriented. All aspects of property attributes from site to structure are fixed by location and thereby once geo–coded become reservoirs for any information associated with that location.

GIS uses a digital globe as the underlying blanket by which layers of geographic data can be applied. The primary level is typically the Assessment Parcel layer. Another layer might be an outline of census tracts; one might be a digitized zoning or flood map. The most compelling feature is that each layer can contain single or multiple types of information. By using a method known as "drill down" an appraiser can select the layers of information relevant to a particular appraisal problem to extract the needed information about a particular property or area.

With the use of task–oriented wizards and pre–formatted checklists appraisers should have the ability to control the types and sources of GIS data being used in a report. This will allow for the most efficient and cost effective method to create the best report in the shortest time. This will also address the need to acknowledge that no two appraisal markets are alike. With the proliferation of GIS databases in local government agencies and many MLS services, the transition from a text based to a GIS based data stream is a logical one. Both appraiser and client will benefit from an increase in consistency, accuracy, and time savings.

Given the nature of real estate in general and the process of its valuation in particular, developing a multi–discipline geographic database seems inevitable. Having access to a resource like a la mode , combined with the increase in Web server hosting of many relevant databases, there are more and more options available for the professional real estate appraiser. Getting the resources and data to gel into a cohesive, seamless set of tools is the challenge in this Labs project.