Point of Beginning

Surveying GIS: How Would a National Cadastre Work?

August 30, 2010
In my last column, I explored the perceived need for a national parcel database. 



I cited emergency response and the home mortgage crisis as the two primary engines driving the campaign for a national parcel database. Hardly anyone disputes that emergency management at the national level could be improved with a national dataset available to all responders regardless of their base location. However, the financial crisis intervention concept is not as well understood. It is based on the premise that identifying troubled areas and analyzing trends can promote the development of intervention strategies. But how would that work?

As it turns out, the national parcel database was one of the key subjects at the Esri Survey and Engineering GIS Summit and International User Conference. Two UC sessions in particular covered the financial intervention application specifically. I’ll summarize them here. To explore the anatomy of the process, we will use ArcGIS10 online to pull some of the actual data the analysts used. (This is one example of “cloud computing.” And, by the way, you can try this at home.)

Bloomfield Township area of Oakland County foreclosures.

Case One: Oakland County, Mich.

Oakland County is north of Detroit. It covers 900 square miles including 62 cities, villages and towns with 450,000 parcels.

By 2008, Oakland County, like many other counties across the nation, began to experience a significant reduction in projected tax revenues. All levels of government operate on projected revenues. A decrease in revenues equals a decrease in services to residents. The cause was quickly identified as an extreme increase in the number of real estate foreclosures. Foreclosures in Oakland County increased by 1200% between 2006 and 2008. But all of the underlying causes of that increase were not well understood.

Spatial analysis of real estate foreclosures using GIS methods began in 2006. The county wanted first to determine foreclosure timelines by identifying “triggers.” “Triggers” occur when a third consecutive mortgage payment is missed. Some interesting patterns emerged from this analysis. Homes built after 1990 had much higher rates of foreclosure. Not surprisingly, adjusted rate mortgages (ARMs) had a higher failure rate than fixed-rate mortgages. But what was surprising was that no correlation with unemployment rates was indicated.

Linking the county-wide Register of Deeds with GIS allowed the County Planning and Economic Development Services Division to better analyze the mortgage crisis. One of the key tools used in the analysis was the ArcGIS Server10 Value Analysis Dashboard, which can be accessed through www.ArcGIS.com. Proceed by clicking on the URL. That brings you to the Interactive Map Page “Value Analysis Dashboard.” There are three basic menu choices here: “More,” “Parcel” and “TaxMap”. The “More” menu has six submenu choices: “Thematic Selection Layer,” “ Foreclosures,” “Sales,” “Assessment Appeals,” Neighborhood” and “Property Value.” Clicking “Foreclosures” shows all of the properties involved in foreclosure proceedings (see Figure 1). By zooming in and clicking on individual parcels, you can query the assessor valuation data (see Figure 2).

One of the findings in Oakland County was that crime rates increased in neighborhoods with abandoned homes. “Hot spot” mapping was used to increase monitoring patrols in vacant properties. Health issues posed by abandoned swimming pools and other potential hazards were investigated.

Additional analyses were performed by matching datasets with the U.S. Department of Housing and Urban Development (HUD) Web site and Bureau of Labor Statistics. Outreach programs were then developed. So far, these have mainly consisted of seminars on financial planning and counseling to distressed mortgage holders. The county is closely monitoring the results of its efforts.


Assessed value of selected property.

Case Two: City of North Las Vegas, Nev.

The City of North Las Vegas (CNLV), Nev., also has developed a foreclosure density analysis program. In 2008, the city began experiencing a significant reduction in tax revenues. The Department of Social Services used GIS data to identify predictors for potential foreclosures (see Figure 3).

Foreclosures were first broken down by subdivision. Social Services was the lead agency because mitigation was the intention of the program from the beginning, and a Social Services agency looks for classic social problems in its analysis. Researchers investigated increases in incidences of domestic violence and graffiti in the distressed neighborhoods. But what they looked at was not “adding up.”

After analyzing bank lists and assessor files, researchers determined that foreclosure densities were greatest in areas where the assessed value exceeded the market value. The city then developed a recovery plan based on the Housing and Economic Recovery Act of 2008 (HERA). The Neighborhood Stabilization Program (NSP) provides Federal Grant opportunities based on Zip Codes. The City (CNLV) uses the grant funding to buy properties in areas with the highest number of foreclosures.

The GIS analysis is ongoing. It is a key component in making decisions about where grant funding can be most effective.

Parcel viewer, Clark County, Nev.

The Surveyor's Role

Oakland County and the City of North Las Vegas were the only two groups to formally present their stories on mortgage foreclosure mitigation at the Esri International User Conference. But there are dozens of others using the parcel databases in their geographic information systems to analyze patterns of economic distress. Because there is no national program to coordinate these efforts, they tend to be reactive rather than proactive. A system that shares the information over a broader landscape could produce stronger long-term comprehensive solutions to these economic crises when they arise.

So what does all this have to do with surveyors? That’s a fair question. But it’s about the economy, isn’t it? Surveyors (like everyone else) have difficulty finding work in a depressed economy. Surveyors do better when the housing market is strong. Those two issues are inexorably linked. I would not go so far as to say GIS is coming to the rescue, but if I did, I wouldn’t be totally wrong. Geography does, in fact, connect people.



Michael L. Binge is a private GIS consultant, certified GIS professional and licensed land surveyor in Arizona, California and Colorado.

Intervention Lingo

CAMA - Computer Assisted Mass Appraisal. A CAMA is a model that allows tax assessors to use uniform models of standardization to fix property tax rates. Integrating CAMA models with GIS data makes the spatial data concurrent with the tax valuation model.

NSP - Neighborhood Stabilization Program. The NSP is a part of the Community Development Block Grant (CDBG) offered through the U.S. Department of Housing and Urban Development (HUD). NSP grantees develop their own programs using CDGB guidelines for eligibility. The full details can be found through the HUD Web site at www.hud.gov.