Digital Mapping Techniques '02 -- Workshop Proceedings
U.S. Geological Survey Open-File Report 02-370

Surveyors and GIS Professionals Reach Accord

By Bruce A. Joffe, AICP

GIS Consultants
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Oakland, CA 94612
Telephone: (510) 238-9771
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e-mail: GIS.Consultants@joffes.com

INTRODUCTION

BACKGROUND

The GIS-related concerns included a general perception that the language of the current NCEES Model Law on Surveying can be interpreted to over-reach the legitimate professional jurisdiction of the practice of surveying with regard to the creation and maintenance of maps and databases in GIS. Surveyors' concerns, recognized by all the Task Force members, were that GIS/LIS tools are potentially being used by nonlicensed practitioners in activities that clearly fall within the long-established responsibility of the licensed surveyor.

The goal of the Task Force was to recommend modifications to the NCEES Model Law that would clearly identify those activities requiring the services of a registered professional, in order to safeguard the public health, safety, and welfare. The resulting recommendations have gained the support of each of the seven participating associations. During the fall and winter of 2001-2002, a subcommittee of the NCEES reviewed the recommendations; the recommended modifications of the Model Law were approved by the NCEES at its summer 2002 meeting.

CURRENT LAWS

A literal interpretation of many such laws would conclude that agencies with GIS base maps that are not supervised by Licensed Surveyors are in violation. GIS Professionals regard these laws as exclusionary--prohibiting them from doing the work they have been conducting historically.

Traditional survey map products such as subdivision plats, legal records of parcel boundaries, or construction grading plans are clearly the Surveyors' purview. But what about commercially available road maps that show the location of "fixed works" (streets, bridges, etc.), assessors' tax maps that show the boundaries of parcels, or watershed drainage maps showing contours of the Earth's surface? These maps, and many similar maps, are being created and used in GIS for inventory and analysis. They are not used to define the authoritative location of boundaries or fixed works.

Many Surveyors concede that the law ought to apply only to "survey products" (which these examples are not); nevertheless, the wording of many state laws, and the national model law, do not indicate such flexibility of interpretation. This is the reason for the Task Force's assembly and recommendations.

GIS base maps are referential. They are not the legal record of original survey measurements. They are representations or reproductions of information taken from original documents. As such, GIS maps do not carry legal authority to determine a boundary or the location of fixed works, and, therefore, they need not be supervised or regulated as survey products.

RECOMMENDED PRINCIPLES

1. A distinction must be made in the use of electronic systems between making or documenting original measurements in the creation of survey products, versus the copying, interpretation, or representation of those measurements in such systems.
2. A distinction must be made according to the intent, use, or purpose of measurement products in electronic systems between determining a definitive location versus using those products as a locational reference for planning, infrastructure management, and general information.
3. GIS databases and maps prepared to be simply referential, representational, or diagrammatic portrayals of existing source documents (many of which were compiled by licensed professionals and are a matter of public record) should not automatically fall under the requirement for supervision by licensed professionals, unless the use of the databases and/or maps is intended to serve as authoritative public records for geographic location.
4. GIS-based databases and maps that are intended to be used as the authoritative document to describe or determine the location of parcels, fixed works, survey monuments, elevation measurements, etc., must be compiled under the responsible charge of a Professional Surveyor or Land Surveyor.
5. Because geospatial technologies are changing very rapidly, references to specific technologies should be removed from the NCEES Model Law and state professional codes. The language of the Model Law should concentrate on the practices to be covered regardless of the technologies employed.

The actual text of the Task Force's recommendation for the "Preamble" section of the NCEES Model Law is:

The term "Practice of Surveying or Land Surveying" within the intent of this Act shall mean providing, or offering to provide, professional services involving both (1) the making of geometric measurements of, and gathering related information pertaining to, the physical or legal features of: the earth, improvements on the earth, the space above the earth, or any part of the earth; and (2) utilization and/or development of these facts into survey products such as graphics, digital data, maps, plans, reports, descriptions, and/or projects.

OTHER CONSIDERATIONS

• GIS mapped features should explicitly refer to the source documents from which they were compiled. Such linkage could be achieved by carrying a source document identifier in the database record of each mapped feature or linking to scanned images of those source documents.
• GIS mapped features should contain explicit and easy-to-understand metadata. The public can be reasonably assumed to be protected if they are informed about the locational accuracy, currency, and method of compilation (lineage) of the data in a GIS.
• GIS maps and data should contain an explicit statement of intended use and disclaimer from other uses. Specifically, a disclaimer should state: "This is not a survey product."² (Note that the context refers to the product of Land Surveyors.)
• GIS maps that have been adjusted (rubbersheeted) to create consistent, coherent display maps should retain the original mapped coordinates as feature attributes, as well as metadata describing the transformation adjustments that were made.

While considering these "base-map certification" issues, one also might consider the implications of a "certified base map." Would such certification usurp some of the legal authority for determining land ownership that currently resides with subdivision plats, deeds, and similar source documents? If so, a government-controlled GIS base map would change the legal basis of boundary determination in this country. Such a change must be decided upon by explicit political expression, not simply as a technical consequence.

Certification of GIS Professionals also raises the implication of liability and responsibility. What liability would a Licensed Surveyor or Licensed GIS Practitioner be willing to accept for potential "damages" caused by GIS data errors, or by the inappropriate use of GIS data? These questions remain open for your consideration.

If you have comments, please use the eForum sponsored by URISA at http://www.URISA.org/gispolicy.htm (item #11), or contact the author. Additional information may be downloaded from ftp://joffes.com/.