National Geographical Research Articles

Utilisation de la photogrammétrie aérienne pour les relevés traditionnels de fluctuations des langues glaciaires

Click to increase image sizeClick to decrease image size1 - Historical backgroundSome measurements of glacier snout fluctuations in France date back to a very long time ago, especially those carried out by the former Forestry and Waters Commission, which kept a close, regular check on the behaviour of some twenty Alpine glaciers over a period of 30 - 50 years, ending in 1965. This involved the following operations : - Measurement of glacier front movement with respect to carefully maintained benchmarks Surveys of cross-sections - Occasional measurements of annual glacier movement rates. A satisfactory overall picture of glacier snout fluctuations was obtained in this way. In addition, the survey methods were coherent and ensured continuity of the observed data, which was a considerable asset. Cooperation between various organisations concerned with glacier problems officially began at a meeting of the "Iceand Snow" group of the French Committee at the International Hydrological Decade on 21st April 1967, when the following precise operational programme was drawn up : 1) Aerical photography of all glacier are as in the French Alps and data-plotting to a scale of 1 :25,000. This work is being undertaken by the French National Geographical Institute, which is producing maps to the above scale. 2) Photography of glacier fronts and snouts and data-plotting to a scale of 1:10,000. This work is of special interest to a number of research and other organisations. Twenty-five glaciers were listed for "monitoring" under this programme. The Ministry of Agriculture finally decided in 1973 to resume the public service role it had held in this field until 1965, having realized the need to keep a close, constant watch on the behaviour of the country's glaciers. The Snow Research Division of CTGREF (Rural Engineering, Forestry and Waters Commission) was made responsible for preparing and implementing the survey programme and keeping records of the observed data.2 - Programme of operations, and work completed to dateThe Snow Research Division has concentrated on the twenty glaciers formerly surveyed by the Forestry and Waters Commission. To restore continuity of observed data - a most important requirement - the Division made it its first job to locate and recondition the pre-1965 benchmarks with the minimum of delay. This work was duly completed. As previously mentioned, the surveys are to be carried out by aerial photogrammetry, which involves the following operations : - Stereo-preparation of areas to be covered - Photography - Compilation of a file for each glacier, listing all control points, their Lambert coordinates and those of the pre-1965 benchmarks. Photography is to be completed in three years, by covering one group of glaciers each year. The following work has been completed to date : 1973 : A survey of Mont Blanc glacier snouts, by conventional methods as time was lacking for preparation of a photogrammetrie survey. 1974 : Stereo-preparation for the group of glaciers in the Savoy Alps. Owing to premature snowfall, however, no photographs could be taken. 1975 : Stero-preparation for the group of glaciers in the Oisans Alps, followed by photography of these and the glaciers in the Savoy Alps. The programme for 1976 provides for stereo-preparation and photography covering the Mont-Blanc glacier group. 3. Technical details3.1. Stereo-preparationA number of points to either side of the flight paths are plotted on a Lambert coordinate system. To allow traversing by aerotriangulation at the plotting stage, the flight paths run outside the glacier. The ground points are marked with 1.7 m x 1.7 m black plastic sheets with a 0.6 m x 0.6 m white square in the middle. 3.2. Aerial photography The photographs, to an average scale of 1:15,000, are taken from an average height of 1,500 m, using a "Wild RC 7" 14 x 14 plate camera with an "Aviogon" wide·angle lens of 100 mm focal length. The camera is installed in a "Pilatus" survey aircraft and operates with 80 % overlap. 3.3. Use of the photographs for glacier research The photographs can be used for either of the following purposes : 1) To produce plans to scales of 1:5,000 or 1 :2,000, longitudinal and cross-sections. 2) For direct numerical calculation of changes in volume between camera "takes", using a squaring method or calculating the volume from the longitudinal and cross-sections in much the same way as for calculating excavation volumes on building sites. Either method gives vertical and horizontal point positions to within 0.4 m. Programs are available for both methods.

Tendance générale au relachement de la précision dans l'utilisation de la photogrammétrie aux levés topographiques

This article is a reply to the appeal published in Photogrammetria, 25(5/6), written by Prof. B. Hallert, in which he expressed the opinion that high-precision photogrammetry has a tendency to rest on its laurels—particularly in the field of cartography—an opinion which the present author shares. This article gives details of the precautions taken at the French National Geographical Institute (I.G.N.) of which the author is director, to obtain the maximum precision in altimetry. Results are given which appear superior to those announced in the recent I.S.P. tests. The author favours publication of the data concerning the true precision obtained in the case of largescale topographic surveys carried out by means of photogrammetry. He fears that a relapse in standards of accuracy is to be noted, largely due to the generalization of the use of film instead of plates and to the abandonment of the Porro-Koppe principle.

Reptiles and Amphibians The National Geographical Society

Book Review| September 01 1970 Review: Reptiles and Amphibians, by The National Geographical Society Reptiles and AmphibiansThe National Geographical Society Tom Held Tom Held Search for other works by this author on: This Site PubMed Google Scholar The American Biology Teacher (1970) 32 (6): 371. https://doi.org/10.2307/4443117 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Tom Held; Review: Reptiles and Amphibians, by The National Geographical Society. The American Biology Teacher 1 September 1970; 32 (6): 371. doi: https://doi.org/10.2307/4443117 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentThe American Biology Teacher Search This content is only available via PDF. Copyright 1970 The National Association of Biology Teachers Article PDF first page preview Close Modal You do not currently have access to this content.

The 21st International Geographical Congress in India

The author reports in his paper on the proceedings and results of the 21st International Geographical Congress held in India in November and December 1968. In the almost centenary history of the International Geographical Congresses this was the first Congress held in Asia. The Congress was sponsored by the Government of India and organized by the Indian National Geographical Committee headed by Prof. S. P. Chatterjee. In the meeting proper of the Congress in New Delhi from December 1 to 8, 1968 together 1100 geographers from 49 countries took part. From Czechoslovakia an official delegation consisting of M. Blažek, J. Demek (head of the delegation), V. Häufler, K. Ivanička (secretary of the delegation), A. Koláčný, E. Mazúr, P. Plesník, M. Střída took part in the Congress. The Czechoslovak geographer's read 14 papers in sections, commissions and symposia. The organizing committee has prepared a number of publications for the Congress which have substantially enriched the geographical literature on India and were given a favourable reception. The Czechoslovak geographers also presented some publications to the participants in the Congress. The Czechoslovak representatives took also part in a number of symposia and field excursions organized in various regions of India. The Indian National Geographical Committee and the organizing committee gave much effort to the arrangement of the Congress. They succeeded in the acquirement of the co-operation of most university centres all over India. The standard of the Congress was up to the state and possibilities of the modern Indian geography and the whole country. During the Congress a new executive committee headed by the Polish geographer St. Leszczycki has been elected. The next Congress is to be held in Canada in 1972. The proceeding of the next Congress should be limited to the 24 IGU Commissions in which the main activities of the International Geographical Union in the period between the Congresses is concentrated.

HARNESSING OF WATER POWER IN CHINA

Journal of the American Society for Naval EngineersVolume 72, Issue 3 p. 459-470 HARNESSING OF WATER POWER IN CHINA DR. VICTOR P. PETROV, DR. VICTOR P. PETROV The author is currently a Professor in the Language Division of the U.S. Naval Postgraduate System at Washington, D.C. His many articles have been published in American, British, and German science periodicals. He is a member of the Association of American Geographers, the American Geographical Society, the National Geographical Society, the American Political Science Association and AATSEEL.Search for more papers by this author DR. VICTOR P. PETROV, DR. VICTOR P. PETROV The author is currently a Professor in the Language Division of the U.S. Naval Postgraduate System at Washington, D.C. His many articles have been published in American, British, and German science periodicals. He is a member of the Association of American Geographers, the American Geographical Society, the National Geographical Society, the American Political Science Association and AATSEEL.Search for more papers by this author First published: August 1960 https://doi.org/10.1111/j.1559-3584.1960.tb02389.x AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume72, Issue3August 1960Pages 459-470 RelatedInformation

The width of meteor trails

view Abstract Citations (13) References (1) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The width of meteor trails Hawkins, Gerald S. ; Whipple, Fred L. Abstract . Meteor images have been measured on the original plates of the National Geographical Society Palomar Observatory Sky Atlas. Meteor images were found to be considerably wider than the width of star images of similar intensity. The effect of seeing, photographic diffusion and camera aberration on image quality was considered and a focal correction was applied to allow for the fact that the meteor was not at infinity. From measurements of 55 trails a mean value of 5.3 meters was deduced for the true diameter of the coma surrounding the meteoroid. This is larger than would be expected if the meteoroid were a single body and is probably a result of fragmentation. Publication: The Astronomical Journal Pub Date: July 1958 DOI: 10.1086/107745 Bibcode: 1958AJ.....63..283H full text sources ADS |

National Geographical Meetings in December

National Geographical Meetings in December

A Canadian Geological Explorer

SOME few weeks back it was announced in NATURE that Dr. Robert Bell, F.R.S., of Ottawa had been appointed director of the Geological Survey of Canada. It is an interesting coincidence that Mr. Charles Hallock has recently written and dedicated to the National Geographical Society of Washington, D.C., a paper dealing with his explorations. This American recognition of a Canadian geological explorer is so remarkable that we desire to call attention to it, especially as it gives an idea of the new director's life work, the extensiveness of which will astonish many. Mr. Hallock, who has been acquainted with Dr. Robert Bell for thirty years, is only able to give us a very brief review of what has been accomplished by this exceptionally able and energetic geologist, for the account is a short one, but we feel that it is of such general interest that the following few facts may be stated.

Erosion of the Muir Glacier, Alaska

DR. WRIGHT, in his “Ice Age in North America,” has calculated that the Muir Glacier erodes its bed annually to the depth of one-third of inch (p. 64). and Prof. Harry Fielding Reid, in his very interesting “Studies of the Muir Glacier” (American National Geographical Magazine, March 21, 1892, p. 51), arrives at the still more startling result of three-quarters of an inch per annum. As one who has paid some attention to rates of denudation by various eroding agencies, I felt some curiosity to know in what way these figures were arrived at. I find that these two calculations are substantially the same, the difference arising from Prof. Reid crediting the whole of the erosion to the glacier bed which occupies only half of the watershed of 700 square miles.