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Library Catalogue

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    Union Catalogue of Agricultural Libraries in the Netherlands

    The WUR Library Catalogue contains bibliographic data on books and periodicals held by the libraries of Wageningen University and Research Centre and some 15 associated libraries. Holding data are added to each record.

    Subjects covered include Agrotechnology, Food and Food Production, Plant and Animal Sciences, Soil Science, Geo-information, Landscape and Spatial Planning, Water and Climate, Ecosystem Studies, Economics and Society.

    The joint collections of the participating libraries cover a substantial part of the internationally available scientific literature in these disciplines.

    As far as Dutch scientific literature in these fields is concerned, coverage can be considered near 100%, including much of the so-called "grey literature".

    All titles are entered in their original language. Keywords are added to facilitate subject searching.

    The database is updated every day and now contains over 830.000 records.

Record number 104116
Title Optische Distanzmessung : Doppelbild oder Distanzfaeden
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[door] J.C.O. van Gijsen
Author(s) Gijsen, J.C.O. van
Publisher Wageningen : Pudoc
Publication year 1969
Description 80 p
Notes Proefschrift Wageningen  show all notes
ok verschenen als: Verslagen van landbouwkundige onderzoekingen ; 727
Ook verschenen als handelsuitgave
ISBN 902200208X
Tutors Kruidhof, Prof. A.
Graduation date 1969-09-26
Dissertation no. 452
Author abstract show abstract

In an attempt to automate the double-image distance measurement by photographing the rod image, the errors of telescope and prism must be either eliminated or corrected. In theory, corrections can be made, but in practice they do not appear to be feasible. A description is given of systems which are free of these errors, In these systems the deviations are caused by reflections. Especially in photography they show such disadvantages, that they are of no use in practice. A reasonable solution is obtained by the use of a rod which is marked from the centre into both directions. The results, obtained with this rod are satisfactory.

When measuring distances by the use of stadia hairs, focussing problems appear. These problems are discussed extensively. With the aid of a large series of observations, a formula has been found for the standard deviation in focussing.

A description is given of the possibilities for eliminating the influence of the incorrect focussing. Placing a stop behind the eye piece appears to be the best solution.

In the telescope with external focussing the stop should be placed in the rear focal plane of the eye lens. In the telescope with internal focussing the stop must be placed in the image of the plane, equally far in front of the focussing lens as the focussing lens lies in front of the crosshairs.

The distance measurements by means of double image as well as by means of stadia hairs, using a telescope with external focussing, turn out to be affected by temperature fluctuations in the same manner.

The telescope with internal focussing is more strongly affected by temperature changes.

Measurements of distances by means of stadia hairs with elimination of the influence of incorrect focussing are given. After this elimination both methods of optical distance measurement turn out to be equally accurate.

Online full textINTERNET
On paper FORUM ; STACKS ; NN08202,452
FORUM ; STACKS ; NN08200,452
Keyword(s) (cab) measurement / methodology / mechanics / length / errors / theory / adjustment / instruments / construction / surveying instruments / equipment / optics / geodesy / tachymeters
Categories Geodesy (General)
Publication type PhD thesis
Language German
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