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:: THE "CRITICAL SURFACES" IN THE PHOTOGRAMMETRIC CARDINAL PROBLEM AND THEIR IMPORTANCE AND ELIMINATION IN PHOTOGRAMMETRIC PRACTICE by Dr. W. Hofmann.

Document type:: Multivolume work

Structure type:: Chapter

1S (401) THE “CRITICAL SURFACES” IN THE PHOTOGRAMMETRIC CARDINAL PROBLEM AND THEIR IMPORTANCE AND ELIMINATION IN PHOTOGRAMMETRIC PRACTICE by Dr. W. Hofmann. This report is a summary of the paper on the “Problem of Critical Surfaces in Theory and Practice“ which will be published this year by the German Geodetic Commission. It contains only an exposition of the most important results and omits their rigid development by mathematical calculation. After previous investigations by E. C. P. Poivilliers, R. Bosshardt and R. Finsterwalder, the first general solution to the problem of “critical surfaces” has been supplied by J. Krames. He found by projective-geometric research chat the relative orientation of a picture pair becomes uncertain if 1) the photographed terrain has the form of an orthogonal regular surface of the second order (orthogonal hyperboloid, paraboloid, cone, rotating cy- linder, hyperbolic cylinder, pair of planes), and if 2) the photographic base lies on a so called “principal determinant” of the surface; it may be assumed that an orthogonal-regular surface is produced by two coincident congruent bundles of planes supported by the principal determinant. A discussion as to which of the 8 possible orthogonal regular surfaces of the second order may actually produce a critical case in aero-photogrammetric practice, must start from photographic and morphological possibilities. Critical formations of the terrain may occur in valleys. A valley formation of this type must have an adequate length and width so as it can fully cover one pair of aerial photographs. Furthermore, the valley must not open into side valleys within the area, covered by a picture pair. Otherwise, control points outside the critical area will be available for unequivocal relative orientation. Since a photographic flight is usually made on a level parallel to the bottom of the valley and at a more or less constant height above the bottom, the orthogonal hyperboloid and the orthogonal cone are eliminated right away as critical surfaces for all practical purposes. In either case, the principal determinants are in an oblique position with reference to the valley bottom as regards position and elevation. They may therefore not be used as flight paths or photographic bases. The principal determinants of the orthogonal paraboloid, which must be on the ground itself, cannot be bases for an air photograph. This also applies to the hyperbolic cylinder and the orthogonal pair of planes. Hence, there remains only the rotating cylinder as a critical surface, provided the base of the photo- graph is on one of the straight lines of its convex surface. The rotating cylinder on which the base is on the vertex convex surface line has already been recog- nized by Bosshardt and Finsterwalder to be the most important critical surface. In practice, the hyperboloid and the cone may become critical surfaces if their

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