Last year, the U.S. Department of Housing and Urban Development commissioned a report to study the feasibility of creating a nationwide database of parcel information. This is a difficult task because the parcels are usually maintained by the counties, and the US has about 3200 counties.
The resulting report is remarkably thorough, including a description of the data collection process and the effort required to get the data, and the information contained in each county’s dataset. The effort required varied greatly, with 13% of the counties requiring more than 6 phone calls just to identify a primary contact for the data, sometimes taking 2 hours more of total time.
These difficulties are a major reason that we need more Open Data policies, and why the Open Data movement should eventually move from the municipal level where it is now to push more counties and states to adopt large-scale Open Data policies.