Geodetic Projects Research Articles

Elbasan City's Local Geodesic Network Construction Using Gnss Surveys

This abstract describes how the city of Elbasan's local geodetic support network is being built using GNSSmeasurements, which will have a favorable effect on the city's economic and social development. The acquiredinformation will be used as a fundamental point of reference for all geodetic projects, as well as for engineering, urban,and scientific designs, as well as geological and geographical studies. In order to determine the three-dimensionalposition of the points in the official KRGJSH frame—which is based on the ETRF2000 reference frame of reference tothe European continental coordinate system ETRS89—as well as the official frame KRGJSH (Albanian GeodeticReference Framework), in which all the coordinates—it will be necessary to build the local geodetic support networkand implement GNSS (Global Navigation Satellite System) measurements.

A methodology for transformation between geodetic datums used in Syria

The Global Navigation Satellite System (GNSS) provides geodetic coordinates referenced to the world ellipsoid WGS84, whereas positions are computed on the local ellipsoid adopted for geodetic computation in various countries. Thus, to take advantage of GNSS in geodetic applications, the need arises to transform coordinates from the global ellipsoid to the local ellipsoid. This is usually carried out by applying geometric transformation models to convert coordinates from The Global Geodetic System WGS84 into the local systems used in each country of the world and into the grid coordinates of local systems. Over the past years, with the increase in the utilization of GNSS in several geodetic projects, numerous methodologies are available for the solution of transformation issues. These methods can be classified into three categories, the first is based on direct mathematical formulas, the second on iteration approaches, and the last category depends on direct transformation from the global system to the local system based on the calculation of transformation parameters (three, seven, nine …etc.). In this study, a methodology has been proposed for direct transformation from global geodetic coordinates to local geodetic coordinates for a limited area in Syria. It is based on the properties of the ratio and proportion between the geometric elements of points on global and local ellipsoids without the calculation of transformation parameters. The results are compared with some studied methods (Bursa-Wolf, Molodensky Abridge, and Cassini). The resulting accuracy is about ± 3.5 cm. The main conclusion drawn is that the proposed method provides a promising alternative approach in coordinates transformation. Therefore, the capability of the suggested methodology as a powerful method for converting geodetic coordinates from one referenced frame to another has been demonstrated in this present study.

Study of the Potential of a Local Geoid Model for Extracting the Orthometric Heights from GPS Measurements in Topographic Works

Due to the rapid development and expansion of geodetic applications, the determination of orthometric heights in an accurate manner is considered as one of the most required conditions to carry out such projects. Obtaining orthometric heights using traditional methods of levelling is time and cost consuming. Hence, investigating other techniques that provide the same accuracy, as leveling methods, but requiring less time and cost is very gainful. Recently, satellite positioning techniques and their applications are being used increasingly in geodetic projects. So, it is interesting to study the efficiency of such techniques for obtaining orthometric heights. GPS methods provide highly accurate measurement of ellipsoidal heights. However, the conversion of ellipsoid heights to orthometric heights may be achieved using geoid models. The objective of this research is to study the efficiency of using a local geoid model as an alternative method to obtain orthometric heights from GPS measurements. This paper proposes a methodology to generate such local geoid models. Then, the results of using the generated local geoid model for Jeddah city in Saudi Arabia are presented. These results indicate that the difference among estimated undulations values from the local geoid model and undulations values calculated from leveling techniques ranges from 1.8 cm to -1.1 cm. with a maximum standard deviation of 56 mm. These results confirm that the creation of a local geoid model is an effective method that gives the required accuracy for topographic works. Keywords: GPS/Levelling method, Local geoid model, Krigging method.

Geoinformatics Study at the CTU in Prague

<p>At the CTU in Prague, there is a long tradition of master degree courses in geodesy, geodetic surveying and cartography. Taking into account the fast development of information technologies in recent decades, we decided to prepare a new study program that would combine computer science with a background of geodetic and cartographic know-how. Apart from other sources, our plans were inspired and influenced by the Review of Education Needs, a report prepared by Stig Enemark (Prague 1998), and by our experience from several Virtual Academy workshops.</p><p><br />We have decided to call this program “Geoinformatics” to emphasize the role of computer technologies in collecting, analyzing and exploiting information about our planet. Within this presentation we will explain the basic ideas behind our new study program and emphasize the features that distinguish it from classical geodetic or cartographic programs. We will mention the connection between our new study program and several geodetic and software projects running at our institute – software development for real-time GPS applications, cooperation with the Astronomical Institute, University of Berne, on the development of so-called Bernese GPS Software, the GNU project Gama for adjustment of geodetic networks, etc.</p>

Geoinformatics Study at the Czech Technical University in Prague

At the CTU in Prague, there is a long tradition of master degree courses in geodesy, geodetic surveying and cartography. Taking into account the fast development of information technologies in recent decades, we decided to prepare a new study program that would combine computer science with a background of geodetic and cartographic know-how. Apart from other sources, our plans were inspired and influenced by the Review of Education Needs, a report prepared by Stig Enemark (Prague 1998), and by our experience from several Virtual Academy workshops.We have decided to call this program „Geoinformatics“ to emphasize the role of computer technologies in collecting, analyzing and exploiting information about our planet. Within this presentation we will explain the basic ideas behind our new study program and emphasize the features that distinguish it from classical geodetic or cartographic programs. We will mention the connection between our new study program and several geodetic and software projects running at our institute - software development for real-time GPS applications, cooperation with the Astronomical Institute, University of Berne, on the development of so-called Bernese GPS Software, the GNU project Gama for adjustment of geodetic networks, etc.

Metrication and American Society of Civil Engineers

The American Society of Civil Engineers has been organizationally supportive of the metric system as far back as 1876. The background of supportive actions from that time to the present are described in this paper. This background serves to introduce the report that follows prepared by the ASCE Committee on Metrication (COM) for consideration by the ASCE Board of Directors. The report summarized the results of a questionnaire circulated worldwide to determine the extent, Usefulness, and acceptance of the SI metric system and then presents recommendations to the Board of Direction. The world survey, with responses from 51 countries, indicated essentially a unanimous endorsement of SI, and the ASCE board subsequently adopted the recommendations contained in the COM report. This action resulted in a policy statement supporting the SI system in ASCE and all civil engineering activities, including education; pertinent book, cartographic, and geodetic projects; and in all ASCE publications.

Proceedings of the International Symposium Management of Geodetic Data, 1981

Data management has become a major issue in many phases of geodesy. This is true because many geodetic projects involve very large data sets that must be managed and manipulated by computers. Data received from a variety of sources and often in disparate formats and quality must be sorted, validated, and selected, and then put into a form that can be read and processed by the host computer. Data packages have to be produced in forms required by customers. For some final products, tables, maps, and other visual data presentation graphics need to be constructed from the processed data by automated methods.

Norwegian marine geodetic projects

The hitherto promising finds of oil and gas on the Norwegian continental shelf have increased the general activity in this area considerably. Consequently, the need for better charts and more precise navigational systems have become more pertinent. During the past few years a number of marine geodetic projects have either been planned or embarked upon by various organizations within both the public and private sectors. This article gives a brief review of the Norwegian projects which have special relevance to marine geodesy; this includes the following areas: recommendations, requirements, precision navigation, satellite positioning, reference systems, boundary problems, bathymetry, geological mapping, marine geoid determination, and data base developments. The reference list will give the reader more detailed sources of information.

Visibility of signal cloth under tropical conditions

Experiments were performed on the visibility of signal cloth used in the tropics for hydrographic and geodetic signals. The cloth tested included the normal muslin and bunting in use by the Hydrographic Office and five brilliant fluorescent cloths. Visibility was checked in a relative sense by two impartial naval observers using fresh and faded cloth under various tropical weather conditions. A scale of relative visibility was devised and the data plotted on histograms for ease of comparison.All fluorescent cloths were found to have a high visibility index under sunlight owing to various colors of the cloths. Ordinary bunting and muslin signal cloth, though of lower visibility under most weather conditions, faded less than fluorescent cloth. Estimates of loss in brilliance by fading are given in tabular form. It is concluded that reduction in signal size is possible, with attendent savings in the smaller construction, if fluorescent cloth is utilized on geodetic projects which can be completed before serious fading obviates its visual advantages.