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Titre : Standard base "Loenermark" : report on the results of the measurements performed by T.J. Kukkamaki and T. Honkasalo of the Finnish Geodetic Institute Type de document : Rapport Auteurs : G.J. Bruins, Auteur Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 1964 Collection : Netherlands Geodetic Commission Green series num. 13 Importance : 44 p. Format : 21 x 28 cm ISBN/ISSN/EAN : 978-90-6132-020-3 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Triangulation
[Termes IGN] base d'étalonnage
[Termes IGN] compensationIndex. décimale : 30.32 Travaux de triangulation Résumé : (auteur) [introduction] In 1913 the primary triangulation network of the Netherlands was augmented with a base line. This base line was measured near Stroe and the results of the measurements were published by Prof. Ir. Hk.J. Heuvelink in 1931.*)
The object of this base line measurement was to check the unit of length derived in 1900 from the German base line near Bonn. When the length of the latter proved to be in good agreement with the results of the measurements at Stroe (with an accuracy of 1:2.5 x 106) the primary triangulation of the Netherlands - including the unit of length determination - was considered to be completed.
Apart from the base line measurement at Stroe the only work done in the field of primary length measurements in those years was an occasional comparison in length between the invarwires No. 89, 90 and 91 of the Netherlands Geodetic Commission and the wires No. 285, 286 and 287 belonging to the Topographic Service of the former Netherlands East Indies during the period 1915 - 1922. This occurred when the latter were sent via Delft to the Bureau International des Poids et Mesures for calibration.
It was not until 1957 that primary length measurements in the Netherlands drew attention again. In that year in the Loenermark (near the town of Apeldoorn) a standard base with a length of about 576 m and an accuracy of about 1:107 was measured by the Finnish geodesists Prof. Dr. T.J. Kukkamäki and Prof. Dr. T. Honkasalo using the interference method of Väisälä. The results of this measurements are laid down in the following chapters:
Chapter 1, by the editor, contains the history of the base and a detailed description of the preparations and construction of it.
Chapter 2, by Prof. Dr. T.J. Kukkamäki and Prof. Dr. T. Honkasalo, is the most important part of this publication and deals with the measurements itself and the results. The authors preferred to omit from this publication the more technical description of the interference method and the instruments used. For details of the method etc. the reader is referred to the references at the end of this chapter.
Chapter 3 gives a short description of an auxiliary base constructed in 1960 for the calibration of invar wires of which the length was derived from the interference base.
This base makes it possible to calibrate in the Netherlands invar wires belonging to several institutes and survey departments which until 1957 had to be done in other countries. The Loenermark base has in particular proved its usefulness when in 1960 in German-Dutch collaboration the base of the German primary triangulation near Meppen was remeasured. Use has also been made of the base for the calibration of the rapidly increasing number of instruments for electronic distance measurements.
Prospective users of the standard base are kindly invited to contact the Netherlands Geodetic Commission, Kanaalweg 4, Delft who will gladly give the necessary information.
This is also the place to thank all who contributed to the realization of this base and the publication of its result. First of all sincere gratitude may be expressed to Prof. Dr. T.J. Kukkamäki and to Prof. Dr. T. Honkasalo and through them to the Finnish Geodetic Institute for the measurements and computations. The generous offer of contributing their time and instruments to this work is gratefully acknowledged. The cooperation of the municipality of Apeldoorn who permitted the construction of the base on her territory is greatly appreciated. Sincere thanks are also due to the engineering firm Grabowski and Poort and to the contractor Mr. Reusken who were always willing to comply with the sometimes unusual requests in the design and construction of the base and the sudden wishes of the geodesists in charge.
Many thanks are due to Ir. G. Bakker and Ir. G.L. Strang van Hees for reading the manuscript and suggesting several improvements.
Last but not least thanks are due to Mr. N. van der Schraaf and Mr. H.C. van der Hoek for correcting the manuscript and preparing the lay-out and to the printer W.D. Meinema N.V., who all contributed to give this edition its present form.Numéro de notice : 42645 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport DOI : sans En ligne : https://www.ncgeo.nl/downloads/13Bruins.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=42602 Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 42645-01 30.32 Livre Centre de documentation En réserve M-103 Disponible 42645-02 30.32 Livre Centre de documentation En réserve M-103 Disponible Gravity expeditions 1948-1958. Volume 5 Complete results with isostatic reduction / G.J. Bruins (1960)
Titre : Gravity expeditions 1948-1958. Volume 5 Complete results with isostatic reduction Type de document : Rapport Auteurs : G.J. Bruins, Éditeur scientifique Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 1960 Collection : Netherlands Geodetic Commission Green series num. 11 Importance : 111 p. Format : 19 x 27 cm - cont. cartes Note générale : VOIR AUSSI les autres volumes Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Atlantique (océan)
[Termes IGN] Caraïbes
[Termes IGN] gravimétrie
[Termes IGN] Nord, mer du
[Termes IGN] Pacifique (océan)
[Termes IGN] pesanteur terrestre
[Termes IGN] SurinameIndex. décimale : 30.42 Gravimétrie Résumé : (auteur) After the second World War, the Netherlands Geodetic Commission again took up the organization of gravity measurements at sea. The method of measurement and the apparatus which were developed and used during the years 1923 - 1938 by Prof.Dr. F.A. Vening Meinesz, resulted during that period in the observation of gravity in 844 stations published in: F.A. Vening Meinesz, Gravity Expeditions at Sea, Volume IV, 1923 - 1938, Delft, 1948. Because of the war this investigation was interrupted for ten years, but on the initiative of Prof. Vening Meinesz it was continued in 1948, although he then judged that younger observers should take his place. As before the war, the Royal Netherlands Navy gave its full cooperation to make this scientific work possible. Sincere thanks are expressed for this help, which must be valued the higher as after 1945 the number of submarines of the Royal Netherlands Navy was reduced and consequently there was less opportunity for making a vessel available for gravity expeditions.
The previous volumes I - IV of this series "Gravity Expeditions at Sea" contain only observations made at sea, however this volume V contains also gravity observations on land. These measurements on land were made in Surinam (Dutch Guyana) with an Askania gravimeter type Gs. 9, which was purchased by the Netherlands Geodetic Commission in 1956.
The following expeditions were made in chronological order:
15th September - 9th October 1948, from Rotterdam via Ponte Delgada to Curao.
1st March - 7th April 1949, from Curaçao via Paramaribo and Casablanca to Rotterdam.
23rd January - 22nd April 1951, from Rotterdam via Lisbon-Curaçao-Key-West-Ponte Delgada back to Rotterdam.
20th June - 22nd September 1955, an investigation of the southern part of the North Sea.
10th - 23rd September 1956, an investigation of the northern part of the North Sea.
29th July - 19th August 1957, an expedition in Surinam.
14th - 26th October 1957, a detailed investigation of the North Sea east of Scotland.
18th November - 2lst December 1957, an expedition in the Caribbean and in the Pacific Ocean.
It must be remarked that on the expeditions d. and g., mentioned above, the observations were not made in a submarine because of the shallowness of this part of the North Sea. Not the pendulum apparatus of Prof. Vening Meinesz was used there, but a North-American gravimeter equipped with Robert Ray remote control, which was let down to the sea-bottom. The Royal Netherlands Navy kindly put the frigates Hr. Ms. "Vos" and Hr. Ms. "Fret" at the disposal of these expeditions.
Because the depth of the North Sea increases considerably towards the north, a number of supplementary pendulum observations were made by submarine in the autumn of 1956, so that a complete picture of gravity in the North Sea was obtained.
This publication is divided into three parts:
Part I contains the expeditions in the Atlantic Ocean and in the Caribbean during the years 1948, 1949 and 1951 by the observers G.J. Bruins, R. Dorrestein and H.J.A. Vesseur (see under a., b. and C.) and the expedition in 1957 (see under h.) in the Caribbean and in the Pacific by the observers G. Bakker and L. Otto. These expeditions can be considered as the actual continuation of the work of Professor Vening Meinesz. The observations of these expeditions have been numbered Nr. 845 - 1032, as the last observation in Gravity Observations at Sea, Volume IV, was Nr. 844. A geophysical interpretation of the results of the expedition h. by Prof. Vening Meinesz has been added; it is followed by tables of the numerical results. These tables are arranged in the same way as those in Volume IV.
Part II contains the expeditions d., e. and g. on the North Sea, observer B.J. Collette. The observations have been numbered No. 1033 - 1293 followed by a geophysical interpretation and tables of the results.
Part III contains the expedition f. in Surinam, by J. Veldkamp, with the Askania-Gravimeter Gs. 9. These observations on land have not been numbered. At the end of this part the results have been printed.
The following remarks are made with regard to the tables of anomalies and reductions :
a. In accordance with the recommendation by the Union Géodésique et Géophysique Internationale, the observations have only been reduced by the method of Airy-Heiskanen (R = 0) and not by the method of Hayford-Bowie. Reductions were also computed for regional compensation with radii R = 29.05, 58.1, 116.2, 174.3 and 232.4 km. The indirect effect (Bowie-correction) was not computed either.
b. The topographic and isostatic corrections have been interpreted as corrections to measured gravity, and not as corrections to normal gravity, so that the sign of these corrections is opposite to that of the corrections in Gravity Expeditions at Sea, Volume IV.Numéro de notice : 10671 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport DOI : sans En ligne : https://www.ncgeo.nl/downloads/11Bruins.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54329 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 10671-01 30.42 Livre Centre de documentation Géodésie Disponible
Titre : Gravity expeditions 1948-1958. Volume 5 Complete results with isostatics reduction Type de document : Rapport Auteurs : G.J. Bruins, Éditeur scientifique Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 1960 Collection : Netherlands Geodetic Commission Green series Importance : 111 p. Format : 19 x 27 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Atlantique (océan)
[Termes IGN] Caraïbes
[Termes IGN] gravimétrie en mer
[Termes IGN] instrument de mesure
[Termes IGN] levé gravimétrique
[Termes IGN] Nord, mer du
[Termes IGN] Pacifique (océan)
[Termes IGN] pesanteur terrestre
[Termes IGN] SurinameNuméro de notice : 39731 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=42509 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 39731-01 47.30 Livre Centre de documentation En réserve M-103 Disponible
