Actes du 7ième Congrès International de Photogrammétrie: Actes du 7ième Congrès International de Photogrammétrie

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Multivolume work

Persistent identifier:: 1048858235

Title:: Actes du 7ième Congrès International de Photogrammétrie

Sub title:: Washington, septembre 1952

Year of publication:: 1954

Place of publication:: Amsterdam

Publisher of the original:: Argus [u.a.]

Identifier (digital):: 1048858235

Language:: English

Other Title:: Paralleltitel: Proceedings of the 7th International Congress of Photogrammetry

Corporations:: International Congress of Photogrammetry, 7., 1952, Washington; American Society of Photogrammetry

Adapter:: International Congress of Photogrammetry, 7., 1952, Washington; American Society of Photogrammetry

Founder of work:: International Congress of Photogrammetry, 7., 1952, Washington; American Society of Photogrammetry

Other corporate:: International Congress of Photogrammetry, 7., 1952, Washington; American Society of Photogrammetry

Document type:: Multivolume work

Volume

Persistent identifier:: 104885955X

Title:: Actes du 7ième Congrès International de Photogrammétrie

Sub title:: Proceedings of the 7th International Congress of Photogrammetry

Scope:: circa 800 Seiten in verschiedenen Seitenzählungen

Year of publication:: 1954

Place of publication:: Amsterdam

Publisher of the original:: Argus u.a.

Identifier (digital):: 104885955X

Illustration:: Illustrationen

Signature of the source:: ZS 312(11,2)

Language:: French

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Corporations:: International Congress of Photogrammetry, 7., 1952, Washington; American Society of Photogrammetry

Adapter:: International Congress of Photogrammetry, 7., 1952, Washington; American Society of Photogrammetry

Founder of work:: International Congress of Photogrammetry, 7., 1952, Washington; American Society of Photogrammetry

Other corporate:: International Congress of Photogrammetry, 7., 1952, Washington; American Society of Photogrammetry

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: REMARKS ON THE PENNINGTON PROPOSAL FOR A STANDARD TEST OF STEREOSCOPIC PLOTTING INSTRUMENTS by W. SCHERMERHORN, [...]

Document type:: Multivolume work

Structure type:: Chapter

isure- n the each yr. In mera coor- ipen- ond- REMARKS ON THE PENNINGTON PROPOSAL FOR A STANDARD TEST OF STEREOSCOPIC PLOTTING INSTRUMENTS by W. SCHERMERHORN, Delft, Holland. As aerial photogrammetry is more and more being applied to map production the demand for all kinds of plotting instruments has increased accordingly. Official and private organizations have not only to decide on a certain plotting method, but also on the instrument most suitable for their purposes. In view of the high costs of the instruments, attempts have been made to compare the various types of instruments; therefore literature is often consulted for indications as to their accuracy. Sometimes the future buyer is disappointed, as it proves impossible to make an objective comparison of the various accuracy indications, owing to the fact that the test conditions vary. It stands to reason, however, that attempts are made to compare the instru- ments on the ground of the accuracy of the results obtained. Especially during its period of development, i.e. till 1940, photogrammetry had to compete with terres- trial survey. The surveyor doubted whether the accuracy would be sufficient for his purposes: manufacturers and photogrammetrists tried to dispel his doubts by submitting accuracy indications. Therefore the accuracy always played an impor- tant role. Of course the evaluation of the accuracy of the whole method nearly always coincided with that of the instruments. Since then this attitude has not changed much and the question which of two instruments has the greater accuracy is still the main point. It is still believed that this accuracy can be objectively expressed by one or two figures applicable to all kinds of aerial surveys. If this assumption were correct, some very simple instructions might be drawn up for a final testing method. Application of this method to all kinds of instru- ments would provide a possibility of comparison. As shown below, the problem of comparing instruments is not quite so simple; even the accuracy, however important, only forms part of a total comparison. The second problem — which only arises after an instrument has been taken into use — is the regular control of the adjustment and of the optical-mechanical quality of the instrument. Actually these are two problems. Each manufacturer of (nstruments indicates a method of adjustment, although some differences in the instruments do not always entail a different method of adjustment. It is inappro- priate and also undesirable to prescribe the same adjustment method for all in- struments. It should be left to the manufacturer to indicate those adjustment instructions which he considers best. Furthermore there is the problem of loss of accuracy in the course of time. Although there are instruments which even after 100,000 working hours still produce reliable results (thus when the instrument is carefully handled the loss of serious) there is no doubt that after some years their accuracy decreases. Besides, it is well known that certain differences in accuracy exist between instruments of the same type. It is gratifying that the fine-mechanical industry has succeeded in improving the precision of its instruments. Consequently accuracy can never become 1

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