Geodetic Surveying Research Articles

A new spherical harmonic approach to residual terrain modeling: a case study in the central European Alps

For decades, the residual terrain model (RTM) concept (Forsberg and Tscherning in J Geophys Res Solid Earth 86(B9):7843–7854, https://doi.org/10.1029/JB086iB09p07843, 1981) has been widely used in regional quasigeoid modeling. In the commonly used remove-compute-restore (RCR) framework, RTM provides a topographic reduction commensurate with the spectral resolution of global geopotential models. This is usually achieved by utilizing a long-wavelength (smooth) topography model known as reference topography. For computation points in valleys this neccessitates a harmonic correction (HC) which has been treated in several publications, but mainly with focus on gravity. The HC for the height anomaly only recently attracted more attention, and so far its relevance has yet to be shown also empirically in a regional case study. In this paper, the residual spherical-harmonic topographic potential (RSHTP) approach is introduced as a new technique and compared with the classic RTM. Both techniques are applied to a test region in the central European Alps including validation of the quasigeoid solutions against ground-truthing data. Hence, the practical feasibility and benefits for quasigeoid computations with the RCR technique are demonstrated. Most notably, the RSHTP avoids explicit HC in the first place, and spectral consistency of the residual topographic potential with global geopotential models is inherently achieved. Although one could conclude that thereby the problem of the HC is finally solved, there remain practical reasons for the classic RTM reduction with HC. In this regard, both intra-method comparison and ground-truthing with GNSS/leveling data confirms that the classic RTM (Forsberg and Tscherning 1981; Forsberg in A study of terrain reductions, density anomalies and geophysical inversion methods in gravity field modeling. Report 355, Department of Geodetic Sciences and Surveying, Ohio State University, Columbus, Ohio, USA, https://earthsciences.osu.edu/sites/earthsciences.osu.edu/files/report-355.pdf, 1984) provides reasonable results also for a high-resolution (degree 2160) RTM, yet neglecting the HC for the height anomaly leads to a systematic bias in deep valleys of up to 10–20 cm.

Геодезичне забезпечення відновлення багатофункціонального комплексу ТРЦ «Нікольський» в місті Харків

The application of geodetic surveys is a vital aspect of assessing the destruction of buildings as a result of Russian armed aggression. The study compares Ukrainian and foreign research methods, highlights their advantages and disadvantages. The legislative framework for geodetic support for restoration of buildings on the territory of Ukraine has been analyzed. As international experience has shown, geodetic surveys are an effective tool for assessing the destruction of buildings as a result of military operations. The study is aimed at evaluating the structural integrity on the example of the shopping and entertainment center “Nikolskyi” in the city of Kharkiv. Geodetic methods used to assess structural damage are reviewed, and an overview of the results of these damage assessments is provided. It is investigated how geodetic surveys can be used to assess structural damage in buildings. The purpose of the article is the study of geodetic works and methods of geodetic support for restoration works of the shopping center building. To achieve the goal, the following tasks were performed: analysis of previous experience in this area; the choice of the method of geodetic provision of restoration works; presenting the results of geodetic measurements; interpretation of the obtained results. Method. To obtain research results, special methods are used: constructive and substantive analysis – for the formation of research directions; analytical methods – to process the results of the shooting; mathematical modeling – to determine the amount of destruction and damage to the building. A Leica Geosystems TCRP 1205 tacheometer and other geodetic equipment were used in the study to assess the structural integrity of the shopping center. The combination of geodetic measurements with the use of tacheometers is an important area of application of tacheometers in similar tasks. In addition, classical surveys, using total station geodetic measurements, were performed in conjunction with an automatic strain monitoring system to ensure the accuracy and reliability of the structural integrity assessment. Therefore, using the specified devices, it is possible to accurately measure and analyze the structural integrity of the shopping center. Scientific novelty and practical significance. The scientific novelty of the conducted research consists in the creation of modern approaches to geodetic support for restoration works of buildings that were destroyed as a result of military operations. Original methods of geodetic surveying and a modern instrument base from NVP “Navigation and Geodetic Center” are applied. The proposed geodetic studies demonstrate the effectiveness of using geodetic measurements to assess structural damage to buildings. Deformation values obtained with the help of geodetic studies helped determine the volumes and technology of restoration, which provides important information for engineering works. It has been shown that the use of electronic tacheometer measurements is a reliable and accurate means of determining damage levels and locations even in complex fracture locations. The Leica TCRP 1205 total station accurately measures angles and distances in a reflection-free mode to achieve the highest accuracy of work. In addition, the measuring technology that was applied at the object of research can be used for geodetic research during the detection of shifts and deformations of building structures. Future research could explore the application of geodetic measurements to other types of buildings or structures damaged by military action. In general, the studies carried out reinforce the potential and importance of geodetic measurements for restoration programs that are planned and will be planned in the near future.

Quality analysis of voxel models obtained with remote sensing

Use of the resource potential of the Arctic is impossible without reliable information about the spatial and temporal characteristics of the developed territories. The topographic and bathymetric information are needed to solve engineering and logistic tasks. Furthermore, surveying, geodetic surveying and geological surveys in these territories are limited by climatic conditions and their infrastructural remoteness. That means, that it’s needed to replace classical methods of performing geodetic works and surveys with the presence of workers on the object with modern automated methods of remote sensing of territories. That methods include the technologies of multipath echo-location, aerial or terrestrial laser scanning, photogrammetry and space sensing of the Earth. Despite the differences between these technologies, they are united by the result, the geospatial data, often called a “point cloud”. Such point clouds are not regular in their structure and form 3D-model of the object due to the redundant data, which makes processing, systematizing and storing this kind of the information more difficult. The paper considers the method of generalization of geospatial data, that allows to reduce these disadvantages by approximating local sections of the model with planes that fit into a fragment of a point cloud using the least squares method. The model described in the paper allow to statistically assess the quality of the initial data, to simplify next mathematical processing for solving specific engineering problems, including geomechanical, environmental and glaciological monitoring.

Геодезические основы картографии в Европе в XIX веке

Geodetic surveying comprises the determination of locations on and the dimensions of the earth’s surface at a various scales. In the 19th century, its technologies are those of direct measurement of the earth’s surface combined with astronomical observations. Its social context encompasses all those individuals and institutions involved in the creation, preservation, use, and arrangement of knowledge of the earth. In the introductory part of the paper the author mentions several important events in the history of the 19th century geodesy. Geodetic work on determining the size of the Earth by measuring the lengths of the meridian arcs continues in this century. An international surveying organization was established and the international meter convention adopted. Basing on a detailed research of geodetic surveying in Central, Eastern and Southeastern Europe in the 19th century, a part of these surveys is presented that relates to Switzerland, Austro-Hungarian Monarchy, Austria, Hungary, Slovenia and Croatia. Common to all these geodetic surveys is that they were necessary for the development of cartography and were carried out by military institutions. The developed geodetic networks are characterized by the use of different ellipsoids, different prime meridians, different coordinate systems and their origin. In the area under consideration in the 19th century, there were five different ellipsoids in use suggested by Bessel, Bonenberger, Schmidt, Valbeck and Zach. Prime meridians were

FEATURES OF CONSTRUCTION OF DIGITAL RELIEF MODEL ACCORDING TO THE RESULTS OF GEODESIC SURVEYING LOCATIONS

Topographic maps in digital and electronic forms are created on the basis of available paper topographic maps or on the basis of primary materials of geodetic surveys. Geodetic surveys are performed both by ground methods, without the use of photogrammetric materials, and on the basis of materials obtained as a result of ground phototheodolite or aerial photography. The construction of a digital terrain model is a multi-stage process, which consists of a significant number of interconnected operations performed at the stage of in-house processing of the results of geodetic measurements carried out during engineering and geodetic surveys. The quality of the final result of modeling depends on the quality of each stage of construction of a digital terrain model, so it is extremely important to pay attention to all technological processes of model construction. The digital relief model is considered as an ordered set of triangular faces constructed by the Delaunay algorithm. The main condition of this type of triangulation is that in the middle of the circle described around any triangle can not be the vertex of another triangle. Construction of a digital terrain model based on the results of geodetic surveying of the area in the general case can be divided into several stages. At the beginning, an automated construction of triangulation is performed on the basis of the results of geodetic measurements, which carry information about three-dimensional coordinates of survey points. Allotments adjust the display of horizontals. Regardless of the selected surface display style, the surface model is a grid of triangles. At the next stage of construction of the digital model of a relief carry out visual control of the created model and if necessary carry out editing of elements of a surface and change of position of edges of triangulation for change of position of horizontals. The last stage of building a digital terrain model based on the results of geodetic surveying of the area is the design of modeling results, the application of individual styles of reflection for individual areas of the surface and the creation of mountain strokes and signatures of horizontals.

Peculiarities of geodesic works with the use of UAVs for the needs of land management

It is determined and substantiated that the most popular type of survey activity for land management is the use of unmanned aerial vehicles, as most traditional methods of geodetic surveys are not effective enough today, they can not provide the required measurement accuracy, especially for landowners and land users. , is very important. An approximate algorithm for the use of unmanned aerial vehicles to solve geodetic problems of land management of united territorial communities, which includes stages of preparation from re-survey to create a digital terrain model, the advantages of using unmanned aerial vehicles over traditional types of geodetic surveys. analyzed a number of features of the use of unmanned aerial vehicles in geodetic surveying for the needs of OTG land management, calculated the economic efficiency of this type of geodetic surveys on a specific example, namely the village of Gamaliyivka Pustomyty district of Lviv region and compared the comparison of traditional costs and time training and the use of unmanned aerial vehicles. At the same time, the ways of improving the process of aerial photography with the help of UAVs are presented both at the normative and at the organizational and technical level. namely, the settlement of Gamaliyivka, Pustomyty district, Lviv region, and a comparison of the cost of time and money in comparison with the traditional method of geodetic surveys and the use of unmanned aerial vehicles. At the same time, the ways of improving the process of aerial photography with the help of UAVs are presented both at the normative and at the organizational and technical level. namely, the settlement of Gamaliyivka, Pustomyty district, Lviv region, and a comparison of the cost of time and money in comparison with the traditional method of geodetic surveys and the use of unmanned aerial vehicles. At the same time, the ways of improving the process of aerial photography with the help of UAVs are presented both at the normative and at the organizational and technical level.

Coral Reef Monitoring by Scuba Divers Using Underwater Photogrammetry and Geodetic Surveying

Underwater photogrammetry is increasingly being used by marine ecologists because of its ability to produce accurate, spatially detailed, non-destructive measurements of benthic communities, coupled with affordability and ease of use. However, independent quality control, rigorous imaging system set-up, optimal geometry design and a strict modeling of the imaging process are essential to achieving a high degree of measurable accuracy and resolution. If a proper photogrammetric approach that enables the formal description of the propagation of measurement error and modeling uncertainties is not undertaken, statements regarding the statistical significance of the results are limited. In this paper, we tackle these critical topics, based on the experience gained in the Moorea Island Digital Ecosystem Avatar (IDEA) project, where we have developed a rigorous underwater photogrammetric pipeline for coral reef monitoring and change detection. Here, we discuss the need for a permanent, underwater geodetic network, which serves to define a temporally stable reference datum and a check for the time series of photogrammetrically derived three-dimensional (3D) models of the reef structure. We present a methodology to evaluate the suitability of several underwater camera systems for photogrammetric and multi-temporal monitoring purposes and stress the importance of camera network geometry to minimize the deformations of photogrammetrically derived 3D reef models. Finally, we incorporate the measurement and modeling uncertainties of the full photogrammetric process into a simple and flexible framework for detecting statistically significant changes among a time series of models.

Assessment of the Three-Dimensional Model Produced by Photogrammetric and Geodetic Surveying Techniques

A combination of close-range photogrammetry techniques and geodetic surveying techniques are used to produce the three-dimensional model, which is one of the major tasks in the field of surveying at present because it is used in many engineering applications, industrial, medical and in cultural heritage objects which requires regular monitoring because of the high accuracy and reliability needed to conduct the measurements. The study area was in the university of Baghdad, specifically for the building of the university tower this research has been produced the three dimensional model of the tower depending on the overlapping ground images captured by a digital camera and the total station instrument used to measure the coordinates of ground points distributed on the university of Baghdad tower. The mathematical model used in this study is the direct linear transformation method to intensify ground points which are used to produce the three-dimensional model of the university tower. Also, a photogrammetric program is used to compute the object space coordinates from the point cloud three-dimensional modeling.

On determining orthometric heights from a corrector surface model based on leveling observations, GNSS, and a geoid model

Abstract Leveling is a traditional geodetic surveying technique that has been used to realize a vertical datum. However, this technique is time consuming and prone to accumulate errors, where it relies on starting from one station with a known orthometric height. Establishing orthometric heights using Global Navigation Satellite Systems (GNSS) and a geoid model has been suggested [14], but this approach may involve less precisions than the direct measurements from leveling. In this study, an experimental study is presented to adjust the highly accurate leveling observations along with orthometric heights derived from GNSS observations and a geoid model. For the geoid model, the National Geodetic Survey’s gravimetric geoid model (TxGEOID16B) and hybrid geoid model (GEOID12B) were applied. Uncertainties in the leveled height differences, GNSS derived heights, and the geoid models were modeled, and a combined adjustment was implemented to construct the optimal combination of orthometric, ellipsoidal, and geoid height at each mark. As a result, the discrepancy from the published orthometric heights and the CSM (Corrector Surface Model) based adjusted orthometric heights with GEOID12B showed a mean and RMS of -8.5 mm and 16.6 mm, respectively, while TxGEOID16B had a mean and RMS of 28.9 mm and 34.6 mm, respectively. It should be emphasized that this approach was not influenced by the geodetic distribution of the stations where the correlation coefficients between the distance from the center of the surveying network and the discrepancy from the published heights using TxGEOID16B and GEOID12B are 0.03 and 0.36, respectively.

Numerical Study of Usefulness on Statistical Testing in Geodetic Surveying of Japan

Numerical Study of Usefulness on Statistical Testing in Geodetic Surveying of Japan

О необходимости актуализации строительных норм и правил по инженерно-геодезическим изысканиям для районов Крайнего Севера

Specific examples substantiate the need for actualization of building codes and rules for engineering and geodetic survey of corridors of linear communications in the Far North regions for areas with perigome heaves of permafrost. It is emphasized that in order to ensure reliable operation and ensure the safety of the operation of gas mains in SNiP, recommendations should be made on the metric characteristics of the location of the communication corridors relative to the upper and lower component of the hillocks. It is recommended that the distance to the nearest pipeline be at least 100 meters from the upper component of the bougram, and from the lower component not less than 50 meters. It is necessary to regulate the order of the pipelines in the corridor. The oil pipeline is proposed to be designed as the final one in the corridor, that is to say, the maximum distance from the boundary of the hillock, as its temperature is much higher, which may help to thaw the hillock. In order to increase the efficiency of engineering and geodetic surveying to detect and establish the distribution boundaries of the lower component of the permafrost drill, it is recommended to use an instrumental survey complex. This complex allows not only transportation of equipment in winter and summer field seasons, but also practically simultaneously perform geodetic, geological work with georadar survey of the territory (Patent of the Russian Federation for utility model N 164037 dated August 1, 2016).

Strategic Development Priorities of Geodetic Surveying and Navigation Support for the RF Armed Forces

Strategic Development Priorities of Geodetic Surveying and Navigation Support for the RF Armed Forces

MONITORING OF MASJED-SOLEIMAN EMBANKMENT DAM’S DEFORMATION USING A COMBINATION OF INTERFEROMETRIC SYNTHETIC APERTURE RADAR (INSAR) AND FINITE ELEMENT MODELING

The fresh water shortage is one the most important challenges in many countries like Iran. So there have been incentives to manipulate and manage water resources by constructing dams. Clay core embankments are one of the most popular dam structures. A layer of clay can be a reliable obstacle in front of water stream. However, because of the soil’s nature, these kinds of dams have the potential of instability. Thus deformation of clay core dams should be monitored frequently. The aim of this study is to use the combination of Interferometric Synthetic Aperture Radar technique (InSAR) and Finite Element Modeling (FEM) for dam’s deformation monitoring. For the InSAR analysis we used data from ENVISAT sensor and processed those using Small BAseline Subset (SBAS). We show that InSAR is an invaluable approach to monitor clay core dam’s deformation in specific circumstances. The deformation derived from InSAR was used as an initial condition in Finite Element Modeling. The case study is Masjed Soleiman Dam which is situated in South West of Iran. We used 19 ASAR images of ENVISAT sensor from 2003/8/22 to 2010/5/7. The process of ASAR images showed maximum velocity of 11 mm/year in LOS direction at central lower areas of dam. These results were compared with Geodetic Surveying Operations at four points on dam and the average agreement of 77 percent was obtained. The results of ENVISAT data have a good consistency with FEM results. Horizontal and vertical displacements derived from instrumentations and modeling are plotted versus depths. There is a good agreement between modeling results and instrumentations data.

Precision Analysis of Trimble Rtx Surveying Technology with Xfill Function in the Context of Obtained Conversion Observations

Abstract As a result of traditional geodetic surveying we usually achieve observations which are then used for calculating rectangular coordinates onto a plane along with precision evaluation. In this article the surveying methods are presented in which the situation is different. Test measurements were carried out, consisting in the measurement of a fragment of detailed control network in RTK (Real Time Kinematic) and RTX (Real Time Extended) mode with xFill function. First, the rectangular coordinates onto a plane (through the transformation of data ellipsoidal) were obtained, on the basis of which the conversion observations were determined and they were compared with each other, as well as with reference parameters - conversion observations out of detailed control network adjustment with use of the method of least squares. The results of the study allow to verify the precision and application possibilities of conversion observations obtained thanks to Trimble RTX technology with xFill function. Application of this surveying method in typical geodetic tasks is fully justifiable. Nevertheless, it is recommendable to be aware of the correlations of absolute or relative values obtained in RTX procedure to reference parameters, which in turn will enable conclusive verification of the possibilities of Trimble RTX technology application in certain geodetic surveys.

Global height system unification with GOCE: a simulation study on the indirect bias term in the GBVP approach

One of the main objectives of ESA’s Gravity Field and Steady-State Ocean Circulation mission GOCE (Gravity field and steady-state ocean circulation mission, 1999) is to allow global unification of height systems by directly providing potential differences between benchmarks in different height datum zones. In other words, GOCE provides a globally consistent and unbiased geoid. If this information is combined with ellipsoidal (derived from geodetic space techniques) and physical heights (derived from leveling/gravimetry) at the same benchmarks, datum offsets between the datum zones can be determined and all zones unified. The expected accuracy of GOCE is around 2–3 cm up to spherical harmonic degree nmax ≈ 200. The omission error above this degree amounts to about 30 cm which cannot be neglected. Therefore, terrestrial residual gravity anomalies are necessary to evaluate the medium and short wavelengths of the geoid, i.e. one has to solve the Geodetic Boundary Value Problem (GBVP). The theory of height unification by the GBVP approach is well developed, see e.g. Colombo (A World Vertical Network. Report 296, Department of Geodetic Science and Surveying, 1980) or Rummel and Teunissen (Bull Geod 62:477–498, 1988). Thereby, it must be considered that terrestrial gravity anomalies referring to different datum zones are biased due to the respective datum offsets. Consequently, the height reference surface of a specific datum zone deviates from the unbiased geoid not only due to its own datum offset (direct bias term) but is also indirectly affected by the integration of biased gravity anomalies. The latter effect is called the indirect bias term and it considerably complicates the adjustment model for global height unification. If no satellite based gravity model is employed, this error amounts to about the same size as the datum offsets, i.e. 1–2 m globally. We show that this value decreases if a satellite-only gravity model is used. Specifically for GOCE with nmax ≈ 200, the error can be expected not to exceed the level of 1 cm, allowing the effect to be neglected in practical height unification. The results are supported by recent findings by Gatti et al. (J Geod, 2012).

Практика створення в Україні інформаційно-вимірювальної GNSS-системи та мережної VRS-технології забезпечення геодезичних і кадастрових зйомок

Практика створення в Україні інформаційно-вимірювальної GNSS-системи та мережної VRS-технології забезпечення геодезичних і кадастрових зйомок

Joseph F. Dracup (1920–2000)

Joseph F Dracup, a Life Member (Geodesy, 1973) and Benefactor of the American Geophysical Union, died January 16, 2000, at the age of 79. Joe was recognized as the most outstanding expert in the field of classical (pre‐GPS) geodetic surveying at the National Geodetic Survey (NGS) following the retire‐ments of Charles Whitten and B. K. Meade in the early 1970s.His career with the Coast and Geodetic Survey and its geodetic offshoot, NGS,spanned almost 40 years, culminating in the position of Chief of the Control Networks Division from 1973 until his own retirement in 1979.

Geodetic Surveying Of Railway Objects

The paper includes the description of geodetic activities using computer and plotting support for the construction of the traffic objects in the railway engineering. The main principles of monumentation and adjustment of the setting-out network are presented among the most common kinds of surveying methods. The requirements for the apparatus equipment and its precision of measurement. Two step setting-out of the traffic objects and control measurement during their construction process. The measurement of deformation values during the load test of constructions. The relation of the required accuracy between deformation values and surveying accuracy. The cyclic measurement for the purposes of the diagnostics of the spatial traffic objects changes. Geodetic surveying using computer support for the construction of bridges across the river Vah in Zilina. The software utilization support for the geodetic survey and cartographic work for the railway engineering

The Geography of Ashkenaz: On the Development of an Ethno-Geographic Information System (EGIS)

6 SHOFAR THE GEOGRAPHY OF ASHKENAZ: ON THE DEVELOPMENT OF AN ETHNOGEOGRAPHIC INFORMATION SYSTEM (EGIS) by Neil G. Jacobs Joseph c. loon Neil G. Jacobs is Assistant Professor of Yiddish language and linguistics in the Department of Judaic and Near Eastern languages and literatures, The Ohio State University . He received his Ph.D. from Columbia University in 1984. He is the author of Economy in Yiddish Vocalism: A Study in the Interplay ofHebrew and Non-Hebrew Components (Otto Harrassowitz Verlag: Wiesbaden, 1990), as well as several articles on Yiddish linguistics. Joseph c. Loon is Assistant Professor in the Department of Geodetic Science and Surveying and the Department of Geography, The Ohio State University. He received his Ph.D. from The Ohio State University in 1978. His research and publication are in the areas of topographic mapping and land information science. 1. Ashkenaz and Geography: An Introduction Ashkenazic)ewish civilization traces its origins back approximately one thousand years. In his classic work History of the Yiddish Language,l Max iRistory of the Yiddish Language. 2 vots. (Chicago and London: U of Chicago Press, 1980). This is a translation of the first tWO volumes of Weinreich's four-volume Geshikhte fUll der yidisher shprakh: bagri)i/, faktn, lIletodn (New York: ¥NO, 1973). The first two volumes of Geshikhte consist of text, while volumes 3-4 consist of notes, references, and comments on the te.'(!. Volumes 3-4 currently remain unpublished in English translation. Vol. 10, No. 4 Summer 1992 7 Weinreich (p. 45ff) links the rise of Ashkenaz to that of Sepharad (at approximately the same time) as signaling the beginning of the "European period in Jewish history," a period which lasted until the current century. Weinreich describes this in terms of a shift of "the center of gravity" of Jewish existence-from earlier centers closer to the Middle East-to Europe. Ashkenazic Jewry arose when Jewish populations settled on German lands, came into contact with non-Jewish Germans (and others), and-in time-created a Jewish Diaspora civilization which was distinct from other Jewish Diaspora civilizations in language (yiddish), culture and way of life, religious observance, and more. According to the generally accepted view, as found in Weinreich,z Ashkenazic3 Jewry arose when significant numbers of Jews from parts of France and Italy began-over one thousand years ago-to settle "on the banks of the Rhine and Moselle, in the area designated by the Jews as Loter." With Later as the nucleus, the territory ofAshkenaz expanded through migration, primarily to the east, south, and southeast, beginning in the eleventh and twelfth centuries4 though later to the north and northwest as well. In this traditional view, the main geographic history of Ashkenaz is thus viewed almost solely in terms of expansion from Later outward, i.e.: (1) the birth of Ashkenaz on western German lands (Loter); (2) in the early centuries, the center of gravity of Ashkenaz still on German lands, but now including eastern German lands, i.e., Bavaria; (3) later expansion further eastward through Bohemia and Moravia; (4) still later expansion to Poland and other lands of Eastern Europe. More recently, it has been argued by WexIer5 -on linguistic and ather grounds-that the origins of Ashkenazic Jewry are to be found not on western German lands, but rather to the east, on lands historically 'History of the Yiddish Language, p. Iff. 3The name- Ashkenaz was used in medieval Hebrew 10 refer 10 German peoples and German lands. The name Ashkenaz predates the Jewish Diaspora. It is found in Genesis 10:3 as a male anthroponym, referring to a son of Gomer.·Weinreich, p. 3. sPaul Wexler. E.•plorations in Judeo-Slavic Linguistics. Lciden: E. ]. Brill, 1987; "Yiddish-The Fifteenth Slavic Language." International Journal of the Sociology of Language (1991): 9-150. 8 SHOFAR populated by both Slavic and Germanic populations. In Wexler's view, these Jews later encountered-via mutual migrations and settlements-a separate Jewish population which originated on western German lands, that is, in Loter. According to Wexler, even as these historically distinct Jewish groups eventually blended together, their earlier distinctness has left behind linguistic and other traces. While the precise details on the historical and...

Kinematic GPS Land Survey—Description of Operational Test and Results

A kinematic GPS (Global Positioning System) survey was performed by the National Geodetic Survey to determine the feasibility of using the method operationally on some geodetic surveying projects. The method of the experiment is described, and results from two GPS data reduction packages are presented along with results of a terrestrial survey performed on the same network of stations. Operationally oriented discussions of the kinematic method., project planning and execution, and suggestions for future kinematic software and hardware are included. The antenna swap method of determining integer biases is described. The survey demonstrates that with little modification of equipment or software, it is possible to implement kinematic surveying as a standard mode of operation on many NGS (National Geodetic Survey) projects. The results of the survey indicate that with station occupation periods of 2 min the repeatability of base line vector components determined by kinematic methods will be subcentimeter.