VIIIth International Congress of Photogrammetry: National reports

Fagerholm, P. O.; Lycken, L. E.; Thunberg, A.; Öhlin, K. A.

Bibliographic data

Multivolume work

Persistent identifier:: 1048861678

Title:: VIIIth International Congress of Photogrammetry

Sub title:: Stockholm, Sweden, July 17 - 26, 1956

Year of publication:: 1957

Place of publication:: Stockholm

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 1048861678

Language:: English

Other Title:: Paralleltitel: VIIIe Congrès International de Photogrammétrie

Editor:: Fagerholm, P. O.

Corporations:: International Congress of Photogrammetry, 8., 1956, Stockholm; Board of the VIIIth International Congress of Photogrammetry

Adapter:: International Congress of Photogrammetry, 8., 1956, Stockholm; Board of the VIIIth International Congress of Photogrammetry

Founder of work:: International Congress of Photogrammetry, 8., 1956, Stockholm; Board of the VIIIth International Congress of Photogrammetry

Other corporate:: International Congress of Photogrammetry, 8., 1956, Stockholm; Board of the VIIIth International Congress of Photogrammetry

Document type:: Multivolume work

Volume

Persistent identifier:: 1048997537

Title:: National reports

Sub title:: Stockholm, Sweden, July 17 - 26, 1956

Scope:: circa 260 Seiten in verschiedenen Seitenzählungen

Year of publication:: 1957

Place of publication:: Stockholm

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 1048997537

Illustration:: Illustrationen

Signature of the source:: ZS 312(12,2)

Language:: French

Other Title:: Paralleltitel: Rapports nationaux

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

Contributor:: Lycken, L. E.; Thunberg, A.; Öhlin, K. A.

Editor:: Fagerholm, P. O.

Corporations:: International Congress of Photogrammetry, 8., 1956, Stockholm; Board of the VIIIth International Congress of Photogrammetry

Adapter:: International Congress of Photogrammetry, 8., 1956, Stockholm; Board of the VIIIth International Congress of Photogrammetry

Founder of work:: International Congress of Photogrammetry, 8., 1956, Stockholm; Board of the VIIIth International Congress of Photogrammetry

Other corporate:: International Congress of Photogrammetry, 8., 1956, Stockholm; Board of the VIIIth International Congress 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:: REPORT OF THE FINNISH SOCIETY OF PHOTOGRAMMETRY 1952 - 1956

Document type:: Multivolume work

Structure type:: Chapter

Finland been used in timber inventory, mapping, management, planning work, and in administra tion. I hese photographs cover an total area of about 6 ooo km 2 . Special investigations. A study on the estimation of the growing stock from aerial photographs has been published in 1955. 1 The study is divided into two major parts. The first part is based upon stand material measured on ground. The mean height, crown closure, and crown diameter are studied as growing stock characteristics. Measurements from aerial photographs make up the second part. The photographic scale of the material is in South Finland 1 : 10000 and in North Finland 1 : 15000. Both pan chromatic and infrared material are used. The height measurements are carried out using parallax and shadow methods. Standard mean error of the estimate fluctuated from 0.9 to 2.9 m. The crown closure is measured by dot grids and density scales and the standard error of the measurements fluctuated from g to 16 per cent. The diameter of the dominant crown is measured by measuring wedge, micrometers, and diameter scales, the standard error of the estimate fluctuating from 0.58 to 1.6 m. The systematic error was rather high and after excluding it the limits for standard error are 0.42 and 0.66 m. The standard error of estimate for the growing stock volume was approximately 30 per cent and for mean diameter 15 per cent. Lake regulation and water power planning. During the period 1952— 1955 photogramme try has become established in use for mapping in connection with planning of lake regulations and water power plants. Besides that the pictures as such have been employded in many preliminary investigations, single pictures and stereo photogramme try have been side by side used in these mappings. Single picture photogrammetry has been especially used in shore investigations of lake reservoirs. Partial enlargements from normal-angle pictures 1 : 20 000 were rectified into 1 : 4 000 so that the area to be mapped is covered with photo sheets. Using these sheets, 0.25 m contours were leveled in the terrain between the upper and the lower water level in the reservoir. This strip comprises only a few metres in the vertical direction. The field investigation has also been made on these sheets in connection with the levelling. The sheets thus obtained are also used as a basis for maps required by appraisal of agricultural and other losses. The relief displacement has no important effect because of the flatness and narrowness of the shore area to be investigated. These methods have given good results on the populated lakeside areas of South-Finland, where the regulation height is relatively low and a high contour accuracy is needed requi ring a small contour interval (0.25 m). Since about 1952 the focus of the reservoir and power plant planning has moved into the sparsely populated North-Finland, where high regulation levels are necessary. For this reason stereophotogrammetry has become more and more predominant, displacing single picture methods almost entirely in 1955. During 1952—1954 the most part of the river Kemijoki has been mapped at the scale of 1 : 4 000 with one meter contours. The aerial photography 1 : 20 000 was made with a Zeiss wide-angle camera RMK 10/18 X 18, flying altitude 2 000 m. The extension of the horizontal control and plotting of the map were accomplished with Zeiss stereoplanigraphs. Vertical control was established by leveling. The total area mapped in this way covers 426 km 2 . In 1955 the power companies of the Government have established their own photogram- metric bureau, and purchased two autographs, Wild A 8 and A 7, accompanied by a Wild camera RC 5 a. During 1955 a total of 2 155 hours was used for the mapping work, which consisted of 282 km 2 maps in 1 : 4 000— 1:10 000, photographed with a wide-angle camera 1 N y y s s 6 n e n, A a r n e: On the estimation of the growing stock from aerial photographs. Comm. Inst. Forest. Fenniae 46.1 Helsinki 1955. See also: Ilvessalo, Yrjo: On the correlation between the crown diameter and the stem of trees. Ibid. 38.2, Helsinki, 1950.

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