in Chapter 2 as: “First, it must permit correlation of real property boundary-line data with topographic, earth science, and other land and land-related data. Second, it must be permanently monumented on the ground so that lines on the maps may be reproduced in the field….”

We recommend that the State Plane Coordinate Systems be used as the basis of the multipurpose cadastres in each state. Monumented points of known location on this system should be distributed throughout the area served, at intervals no greater than 0.2 to 0.5 mile in urban areas and I to 2 miles in rural areas.

Only a handful of the more than 3000 counties of the United States currently maintain a geodetic reference network with a density adequate to support a multipurpose cadastre. Indeed, in only about 10 percent of the 500 counties designated by the U.S. Department of Commerce as “leading” counties in terms of economic activity is there in place an existing primary geodetic framework of sufficient density (spacing of 3 to 5 miles or less) to serve as the starting point for further densification to a level that would support a cadastre.

Significant progress toward establishing multipurpose cadastres thus will require extensive programs of densifying the geodetic control network. Fortunately, several new technologies (described in Chapter 2) for accurately determining the positions of survey control points promise that substantially lower costs per control point will be realized in projects that are organized on a large enough scale to employ them.

The base map of a multipurpose cadastre is the primary medium by which cadastral parcels are related to the geodetic reference framework; to major natural and man-made features such as bodies of water, roads, buildings, and fences; to political boundaries; and to each other. The base map also provides the means by which all land-related information may be spatially referenced to cadastral parcels. It is the medium for determining and expressing locations in continuous space, so that shifts in the locations of the boundaries of cadastral parcels may be entered as necessary in the official records. The map may be stored either in graphic form, on paper or Mylar. for example, or in digital form as a “virtual” map.

Base maps should be prepared to meet United States National Map Accuracy Standards (see Appendix B). Customary map scales for each type of area (urban, suburban, rural, and resources regions), which are in almost universal use today, are listed in Section 3.4.

The cadastral overlay depicts positions of property boundaries in relation to the other features shown on the base map and shows the standard identifier of each parcel, the latter serving as the key to the many other parcel records that can then be based on the multipurpose cadastre. The cadastral overlay could be viewed as a property ownership map that adheres to standards for accuracy of plotting of property boundaries and completeness in display of parcel identifiers—including standards for timely updating to show boundaries and identifiers of newly created parcels. Although the boundary plotted on these maps should meet map accuracy standards,



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