Journal of Surveying Engineering

With the utilization of alternative energy resources in North America have come various mechanisms for protecting access to sunlight. The mathematical aspects of the problem have not been thoroughly treated in the literature. A solar envelope, over a parcel of land, defines the three‐dimensional figure within which objects may be placed without obstructing sunlight to adjoiners during a specific time interval on all days of the year. A mathematical development of the geometry of solar envelopes is presented. A computational example and an analysis of the effects of errors inherent in some assumptions are included. Such treatments are necessary as legal descriptions of solar easements are being prepared and subdivision design constraints include provision of solar access to each lot.

Statistically rigorous densification of horizontal geodetic networks must consist of a simultaneous adjustment of both the densification and the densified networks. Equivalently, the effect of the already adjusted (existing) network to be densified may be rigorously propagated into the densification network, through an appropriately derived weight matrix of the common station positions. The nonrigorous schemes utilize information available on the existing network in a statistically nonrigorous way. In this paper, two main statistically nonrigorous schemes used in practice are recognized. Their results, both mathematical and numerical, are compared to results obtained rigorously. A way to convert the nonrigorous results into rigorous ones practically and economically is also shown.

Resection, the three‐point problem, involves fixation of a new point when directions to three known points are observed from an unknown point. This paper presents an analytical solution to the problem which permits direct substitution of known and observed quantities into a simple formula to determine the coordinates of the unknown point.

Rapid, accurate management of information regarding leasable properties and buried utilities maintenance data has been a continuing problem at many large airports. This paper describes a unique computerized solution to these problems. A computer system has been developed and installed at a recently opened major international airport that provides fully interactive graphics and text reporting to users at various locations throughout the airport. The system links graphic elements to a data base that contains information about each of these elements. Graphic elements may be polygons, points, or lines. Each type of element has its own selected assortment of data needed to satisfy various applications. The system design provides an extremely simple, rapid means of querying the system. Individual elements or areas to be reported may be selected graphically or by keyboard command. Color or black and white prints are available on demand. The system proved to be a major benefit during initial properties leasing. Solutions to utilities problems that became apparent during early operations have also been expedited by use of this system and it has become an essential tool in maintenance operations for the airport.

The new adjustment of the North American Datum of 1983 (NAD 83) is now in its 10th year. To understand the necessity for the new adjustment, a review of the problems encountered with the existing NAD 27 network must be examined. The status of the project is important to the users of geodetic control data because they must begin to plan for the transition from NAD 27 to NAD 83. The problems of the transition are understood, and the National Geodetic Survey (NGS) is already developing information to assist users in adapting to the changes. These changes will involve new coordinate values and a new coordinate system which will affect all levels of control surveying and mapping, including the U.S. Geological Survey's topographic map series.

The PPACG, a regional planning agency, developed an intergovernmental program for joint acquisition of aerial photographs and compilation of a low cost base map. The cooperative effort of local governments provided a greatly needed map product. These maps were made available at varying scales to meet the different requirements of each agency. The cooperative effort saved the region over $15,000. One of the program's major accomplishments was the development of multiple applications of the base map. It has been utilized as a major element of the land information system in the region.