Journal of Surveying Engineering

Since the founding of ASCE in 1852, remarkable changes have occurred in all areas of civil engineering practice, including surveying and mapping. Instruments employed in surveying and mapping in the United States have evolved from compass and chain, through a period of transits and tapes, into another era of optical-reading theodolites, electronic distance measuring equipment, aerial photogrammetry, and finally into the current stage of high-speed computers, the global positioning system, robotic total station instruments, digital photogrammetry, and satellite remote sensing systems. This paper includes three parts: (1) a discussion of the history of surveying and mapping; (2) a description of the current state of the art of surveying and mapping; and (3) some projections on how surveying and mapping may evolve in the future.

Conservation of natural resources is essential to sustain any developmental activity, and such measures especially for soil and water carried out on a watershed basis are very useful for watershed management. In this context, prioritization of watersheds is required for different watershed components so as to take any further relevant conservation measures. Recent technological advances have brought remote sensing and geographic information system (GIS) techniques to the forefront as tools for recommending these conservation measures. In the present study, the topmost priority subwatershed (i.e., Murli subwatershed in the Subarnarekha Basin) among nine subwatersheds forming a major portion of the Nayagram block in the Midnapore district of West Bengal State in eastern India was considered. This subwatershed was further divided into 44 microwatersheds (with areas less than 10 ${\mathrm{km}}^2)\text{,}$ which were prioritized based on morphometric parameters. Accordingly, suitable soil conservation measures were suggested. For the sake of completeness, the number of the microwatersheds in which these proposed check dam sites fall was also identified. From this study, it can be inferred that prioritization of microwatersheds is essential; GIS is handy as well as effective in recommending proper treatment for these microwatersheds.

The Gauss-Bonnet theorem was studied and applied to a geodesic triangle and the results given. The aim of this paper is to take a subject whose results are given mostly superficial treatment and present a more clear and easily understandable introductory treatment for geodesy education.

A new method of checking the alignment of parallel rolls, while they are rotating, is described in this paper. The method utilizes the autoreflection technique, along with a strobe light and photoelectric trigger, to determine the orientation of the normal to a mirror fixed to the end of a roll. Three or more observations of the normal at different rotational positions of the roll allow for the computation of the roll’s rotation-axis orientation. The method was applied to a small machine in both the dynamic (operating) and static (nonoperating) modes. From this application, it was determined that standard deviations of orientations can be expected to be in the order of 4 arcs for the dynamic mode and 2 arcs for the static mode.

A new least-squares solution to the Theil model is presented. The proposed solution is particularly suitable for applications of network densifications. By assuming fictitious observations made on the constraints, the pseudoobservation equation is formed and then solved according to the least-squares principle. Instead of the noninteger degrees of freedom as appeared previously, the proposed solution has an integer degree of freedom. Generally, these two solutions are not identical, although statistically both are unbiased and minimum-variance estimates for the parameters. In addition, the proposed method results in a smaller matrix dimension for the corresponding pseudonormal equation. The unknowns to be solved for in the normal equation decrease in such a way that the more the constraints, the less the unknowns will be.