Saturday, March 13, 2010

Detroit Vacancy Survey – Making Parcel Data Relevant to the Discussion

In February the Detroit Free Press Published an article describing the results of a recently published survey of residential housing in Detroit. The survey was completed by researchers who drove all the streets and completed windshield surveys on the condition of single family residential housing. Quoting from the Detroit Free Press Article ( “A little more than 35% of the city's 343,849 residential parcels are either vacant lots or abandoned shells of buildings. … But the survey also found surprisingly upbeat results in Detroit's most vital districts. The survey found that more than 90% of the city's occupied residential units are in good or fair condition”

The article goes on to discuss the value of this parcel-by-parcel data “In a world where investment decisions and government aid are driven by hard data, the survey offers an unblinking, parcel-by-parcel look of Detroit's condition. Kurt Metzger, a demographer and director of the nonprofit agency Data Driven Detroit, which helped manage the survey, said the parcel data eventually could be merged with other databases -- foreclosures, health and educational statistics, crime patterns -- to allow the most precise imaging ever of a city and its challenges.”

These results are intriguing for Detroit and the parcel-by-parcel information is exactly what was called for in the Land Parcel Data for the Mortgage Crisis (add link to report) report from the May 2009 stakeholders meeting in Washington DC. But beyond the findings that parcel data are valuable to decision makers and an important part of the strategic planning for recovery, these results also raise an interesting question about why was a drive by inventory needed to get this information? The Detroit Free Press Article states “And, in the future, the agency hopes to add advanced mapping software and other tools to its Web site to make the survey results more accessible and useful.” Isn’t this exactly the type of service local government should be providing?

If local governments have automated parcel data linked to assessment rolls, why couldn’t the vacancy and housing conditions be assembled from the accurate and certified assessment data? Why couldn’t this information as well as commercial and industrial property as well as multiple family housing be pulled from assessment files and tied to parcel maps? Given the importance of these findings and the continued property value and mortgage issues facing local economies shouldn’t this data be available everywhere there is parcel mapping?

The other interesting aspect of the results of this survey was that the findings published on the web were generalized to the block level to prevent criminals from targeting vacant houses. But if Google and Microsoft, to name two, are providing street level views of these areas, and criminals can search the web and find this study and determine the block level data, couldn’t they also pull up the street view and look or maybe even just drive by themselves, after all the search radius has been reduced? It is certainly a concern that vacant housing attracts a criminal element but isn’t there an accountability and transparency issue in publishing the locations of the vacant structures? Isn’t this a way for citizens to hold their elected officials accountable? Doesn’t tracking changes in vacant structures (rehab or gentrification of vacant structures), improving vacant lots and tracking condemnation and demolition actions create a visible measureable for public policies?

The enthusiasm and interest expressed by public officials to the results of this survey seem to indicate that providing a web service or even a mobile service on vacancy, condition and tax use classification from an authoritative source that can also show trends and be combined with other parcel based authoritative data like tax delinquency and assessed value is something we all should be considering for our parcel data. It’s one more way GIS and parcel data can be part of the game and part of the discussion.

Land Surveyors, Parcels and GIS

In the March 2010 Professional Surveyor Magazine Craig Dylan published an article titled “A Long Survey” (add link). Mr. Dylan describes a GPS survey along the Delta-Mendota Canal in California completed by BLM Land Surveyors. The article on the use of the GPS is interesting especially the use of the GPS, GNSS and California Surveying Virtual Surveying Network (CSVSN). But as almost an aside he quotes the BLM Land Surveyor Tim Jackson on the time savings with CSVSN and efficiencies the BLM has gained in just five short years. The article also describes the benefits of capturing PLSS, property and right of way monumentation as part of these projects. The surveys found original monuments, identifying where property boundaries may need further survey work and even errors in places where reference monuments were used rather than the actual corners.

Through the canal boundary survey the GPS measurements found trends in subsidence, identifying areas at risk for further subsidence and compared past elevation observations to the new results. This information benefits the canal managers by providing information on where future infrastructure repairs maybe needed and where to watch for particular types of damage arising from subsidence.

Although not mentioned in the article, taking the results of this survey and combining it with other BLM and private land surveys to create a standardized representation of the PLSS that could be used by GIS staff and other land surveyors extends the benefits found by Mr. Jackson.

What if the results of this detailed and well research survey project could be rolled into county parcel mapping easily? The benefits would be extended beyond the source agency to the other agencies. Couldn’t this type of project be studied from a benefits perspective to create a financial case for the role of land surveys in improving decision making, improving the quality of public data sets and improving the public’s perception of public data sets? Isn’t the role of land surveying more than establishing boundaries and improving individual data set quality? Extending the results to support future aerial photography control and supporting infrastructure management decisions puts the land survey directly into the day to day business of decision makers.