Journal of Surveying Engineering

In the stage of transformation of global positioning system coordinates to a national coordinate system, the transformation parameters computed show local changes depending upon the selection of common points used in the transformation. The coordinates of the common points in both coordinate frames, however, contain various errors, which result in the local changes mentioned above. In this context, finding out the effects of possible errors in the coordinate components on the transformation parameters and determining which coordinate component influences which transformation parameter will help in developing alternate transformation strategies that can reduce the local effects. For this purpose, first the differential relations between the coordinates and transformation parameters are investigated on the basis of the three-dimensional similarity transformation, and then the degree of influencing—in other words, the effect order—is determined by investigating the relationship between parameter and geographic coordinate component. In this study the height component has been found to be the most affected component among the coordinates, which influences five out of seven transformation parameters.

The determination of the deformation of a geodetic network is an objective of the analysis of many geodetic deformation measurements. The deformation analysis is a step-by-step procedure, which begins with the global congruency test. If the coordinates of repeated measurements with its variance-covariance matrices of the coordinates and its datum are available, the question, if congruency between different epochs exists, arises. An alternative test procedure besides the conventional method for congruency investigations is proposed, and both methods’ sample solutions are given in the Numerical Example section. The procedure is based on strain analysis. The conclusions about the benefit lack of both methods are discussed in the Conclusions section.

Global positioning system (GPS) solutions offer direct measurements for the dynamic monitoring of long-span and tall civil structures. Timely and correct interpretation of the solutions is essential to improve monitoring and reduce the number of false alarms. In this article, a new approach has been developed that employs the principal component analysis (PCA) of wavelet transformed GPS solutions to detect out-of-control signals. The methodology consists of prefiltering the original GPS solutions via finite infinite response median hybrid (FMH) filter and applying the PCA to Haar wavelet transform (HWT) of the FMH-filtered results. It has been tested off-line using observation data from a tall building monitoring experiment involving GPS and multisensors. Observation data were collected for about seven days in February 2000, including two strong wind periods. The PCA control chart of the wavelet transformed solutions was found to respond better to the wind periods as compared with that of the “raw” solutions. The proposed method can be applied to monitor wind/earthquake or thermally induced responses in the long-term deformation monitoring of large engineering structures by GPS.

As a well-known numerical approximation method, the least squares fitting method is widely applied in surveying engineering. The most important and difficult problem in this method is to determine the type of base function to be used, and polynomial is the most frequently used type. But if the degree of polynomial is too high (⩾7), the normal equations are usually ill-conditioned. When we choose the uniform B-spline as the basis, there are two problems: (1) if we require the known data points to be an equidistant grid, it can only be applied in limited field; and (2) if the known data points are scattered, it is very difficult to obtain satisfactory results by using the uniform B-spline method. The purpose of this paper is to present the least squares fitting method based on a bivariate nonuniform B-spline. The principles and algorithms of this least squares fitting method are developed. Based on this method, two numerical simulations and one application in regional gravity field approximation are discussed.

Many surveyors use the network of global positioning system (GPS) Continuously Operating Reference Stations (CORS) as accurate “free” control monuments in their projects. The National Geodetic Survey (NGS) publishes and maintains coordinates for these stations in terms of X, Y, Z, and latitude, longitude, and ellipsoidal heights. This information is very useful for horizontal positioning but not for vertical positioning. Establishing the orthometric heights of a CORS station will enhance its usefulness to surveyors and geodesists. In this paper, a method for determining orthometric heights for CORS is described and evaluated. The implementation of the proposed procedure at the NJI2 CORS station produced an orthometric height with a standard deviation of ±1 mm.

The aim of this study is to form a dynamic deformation model for landslides. Static and kinematic models used in practice in determining movements do not deal with the mechanical characteristics of the object and the deformation mechanism. They may yield misleading results in interpreting movements. In contrast, dynamic deformation models determine movements regarding the mechanical characteristics of the object and the deformation mechanism. In this study, a dynamic model reflecting the effect of the cause of movement for landslides was used for determining movements. For this purpose, the modeling of the effect of heavy rainfall and large underground water level changes in activating landslides was investigated. A test network was established in a slide area in Maçka County in the province of Trabzon in the northeast of Turkey. The coordinates of network points were computed with geodetic measurements. Underground water levels of the network points were determined with geological and geophysical measurements. Using these data, movements were determined with both kinematic and dynamic models. Results of both models were compared to each other. It was concluded that determining movements with the dynamic model was more suitable than using the kinematic model in landslide studies. It was also concluded that, regarding the difficulties in its construction, the dynamic model should be preferred in cases where human life is in serious danger. As another result of this study, it is shown that before interpreting movements of network points, it is necessary to detect slip surfaces on the study area and then perform the interpretation according to these slip surfaces.

Traditionally, highway vertical curve data have been calculated and tabulated for construction staking. The design drawing showed the parabola drawn using the calculated station-offset information. With the procedure described herein, a draftsperson can draw the parabola, given the station-elevation data on the beginning of vertical curve, the point of vertical intersection, and the end of vertical curve, using any drafting software. The construction staking data can then be obtained directly from the drawing by means of an appropriate command to get the information. There is no need to compute the grade elevation for staking purposes. While the graphical methods are not new, the use of computer-aided drafting (CAD) facilitates obtaining precise solutions from the CAD-computed database, which was not possible with the paper drawings of the past.