An important part of this study was to assess the current status of parcel data in the United States. The committee found that a significant digital parcel data divide exists between various counties. In many parts of the United States, parcel data exist only as lines on paper maps stored in a local courthouse. While about 70 percent of the tax parcels in the United States now exist in digital form, the remaining 30 percent are located in the roughly 2,000 most rural counties. Although these counties have fewer total parcels, they also do not have adequate financial resources to convert their data to digital form. On the other side of the divide, many urban areas are covered by two or three versions of parcel data, and often anyone with a simple web browser can anonymously retrieve information about the ownership, taxes, and value of any parcel by owner name or street address. Many communities routinely align parcel boundaries using digital aerial photographs that precisely display fences, driveways, sidewalks, hedges, and other features that align with property boundaries. In fact, there are parcel data programs that reflect real-time changes in real estate transactions or new street addresses through field-based global positioning system enabled hand-held computers.

As mentioned earlier, there has been a fair amount of federal policy supporting a comprehensive approach to parcel data. However, while the FGDC has designated BLM as the steward for federal land parcel data and the coordinator of cadastral data, a coordinated approach to parcel data, even for federally managed property, does not exist. The most tangible and successful effect of federal efforts has been the FGDC Subcommittee for Cadastral Data, which has made significant progress in the development of standards and coordination with stakeholders. As for federal agency programs to develop parcel data, the National Integrated Land System is the closest thing to a coordinated program, but it remains much more of a set of technologies than a source of parcel data. Meanwhile, there is evidence that federal agencies are acknowledging their need for parcel data to fulfill their missions. For example, the Department of Agriculture’s common land unit program is generating subparcel data to monitor fraudulent crop insurance claims, and DHS has included a detailed specification for parcel data in its geographic data model. This is a tangible recognition of the essential role parcel data can play in improving the level of service from federal agencies. The development of parcel data for Indian lands is also very inconsistent across the nation, due in part to the many additional difficulties that must be addressed when dealing with Indian trust lands.


The committee assessed the challenges, issues, and barriers to the development of a national land parcel data set and found these to be technological or data-related, financial, legal, organizational, and political, as well as problems unique to Indian lands. Although most of the technological barriers have been overcome, issues related to the accuracy and currency of the data still must be addressed. Appropriate funding mechanisms for a national land parcel data set are needed. However, the committee believes that the financial and technical issues are minor compared to the organizational and political ones. With thousands of counties or other government entities as potential producers of parcel data, the organizational issues are complex. It is not a simple task to assemble parcel data that span several counties or states. Overcoming the organizational barriers even among federal agencies has been difficult, as evidenced by the fact that there is no single inventory of federal lands. The lack of nationally integrated land parcel data has led to massive duplication of effort among various levels of government and between the public and private sectors. For example, in the absence of a coordinated public sector approach to parcel data, private firms have acquired local data and teamed with aerial photography companies and commercial digital map providers to develop their own versions of parcel data.

The National Academies of Sciences, Engineering, and Medicine
500 Fifth St. N.W. | Washington, D.C. 20001

Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement