scholarly journals Velocity measurements on Engabreen, Norway

2005 ◽  
Vol 42 ◽  
pp. 29-34 ◽  
Author(s):  
Miriam Jackson ◽  
Ian A. Brown ◽  
Hallgeir Elvehøy

AbstractHorizontal velocity measurements on the lower part of Engabreen, Norway, were made from repeat aerial photography. IMCORR software, which has been widely used to measure velocities from satellite images, was used to make the measurements. This is the first known successful use of IMCORR on aerial photographs. Supplementary horizontal velocity measurements were made from repeat measurements of stakes, giving velocities over different periods and also in areas that are too slow-moving to register a measurable velocity after only a few days.

Author(s):  
Ilya Rylskiу ◽  
Evgeniy Eremchenko ◽  
Tatiana Kotova

Aerial photography is often impossible due to the presence of high clouds with contrasting shadows that do not allow to obtain materials suitable for decryption. At the same time, in a significant proportion of projects in Russia, the snowless season suitable for surveying is very short. The inability to perform aerial photography while flying below the clouds leads to cost increasing. In some cases, projects cannot be completed. Existing software does not allow to solve the problem of equalizing the brightness in the shadows for several reasons. The main reason is the inability to identify the boundaries of the shadows using only the spectral characteristics of the images, the inability to determine the amount of correction for shaded areas. To solve this problem, it is proposed to use reference images of the worse resolution obtained from the satellites. Reference images are used to localize and determine the magnitude of the spectral correction of aerial photographs. The work is performed with single orthophotographs or orthophotomosaics in the same coordinate system. To determine the boundaries of the shaded zones and the values of the corrections in brightness, methods of cartographic algebra on regular data arrays are used. Further, the obtained correction matrices are subject to filtering and are used to correct high-resolution aerial photographs. The paper gives an example of the use of free (or cheap) satellite images to eliminate or reduce the contrast of shadows on aerial photographs with a detail of 20 cm. The created prototype software allows to perform additive or multiplicative correction of an array of individual aerial photographs. The proposed approach requires more time for data processing, but gives much more acceptable results for visual (manual) decryption. The method is not recommended for use when working with images in more than 10 cm, when solving monitoring tasks with frequent repeated surveys, and also, if necessary, to carry out automated decoding using spectral standards.


1996 ◽  
pp. 64-67 ◽  
Author(s):  
Nguen Nghia Thin ◽  
Nguen Ba Thu ◽  
Tran Van Thuy

The tropical seasonal rainy evergreen broad-leaved forest vegetation of the Cucphoung National Park has been classified and the distribution of plant communities has been shown on the map using the relations of vegetation to geology, geomorphology and pedology. The method of vegetation mapping includes: 1) the identifying of vegetation types in the remote-sensed materials (aerial photographs and satellite images); 2) field work to compile the interpretation keys and to characterize all the communities of a study area; 3) compilation of the final vegetation map using the combined information. In the classification presented a number of different level vegetation units have been identified: formation classes (3), formation sub-classes (3), formation groups (3), formations (4), subformations (10) and communities (19). Communities have been taken as mapping units. So in the vegetation map of the National Park 19 vegetation categories has been shown altogether, among them 13 are natural primary communities, and 6 are the secondary, anthropogenic ones. The secondary succession goes through 3 main stages: grassland herbaceous xerophytic vegetation, xerophytic scrub, dense forest.


Planet ◽  
2012 ◽  
Vol 26 (1) ◽  
pp. 31-35
Author(s):  
Dennis Edler ◽  
Nils Lammert-Siepmann ◽  
Carsten Jürgens

Author(s):  
Viacheslav V. Krylenko ◽  
◽  
Marina V. Krylenko ◽  
Alexander A. Aleynikov ◽  
◽  
...  

The study of the relief of large coastal accumulative forms, based on modern technologies, is rele-vant for solving many applied problems. Coastal and underwater bars, shoals, banks are characteristic elements of large coastal accumulative forms’ geosystems. Previously existing methods of relief re-searches, especially underwater, were labor-intensive and expensive. Accordingly, the development and implementation of new methods of geographical research are necessary. The Dolgaya Spit, includ-ing its underwater shoal and the Elenin Bank, is one of the largest accumulative forms of the Sea of Azov. The purpose of our work was to obtain new information on the relief structure and the shoreline dynamics of the Dolgaya Spit based on the use of new research methods. Digital models of surface and underwater relief were built on the basis of processing Sentinel-2 satellite images and data from unmanned aerial photography. The subsequent analysis allowed identify regularities that reflect the current and previous hydro-lithodynamic conditions that determined the transformation of the Dolgaya Spit during its evolution. The fulfilled studies confirmed the possibility of successful use of modern remote methods for studying the relief of coastal accumulative forms.


1983 ◽  
Vol 112 ◽  
pp. 580-583
Author(s):  
Gordon J Barclay

In the 1940s and 50s Mr Eric Bradley, a flying instructor at Scone, noticed and described a series of crop-marks to the W of Perth during attempts to trace the Roman road, from the Gask Ridge, at its last known point near Dupplin Lake some 8-5 km to the SW of the fort at Bertha. In 1969 Dr J X W P Corcoran admirably summarized the evidence available from Mr Bradley's notes and maps, Cambridge University Committee for Aerial Photography (CUCAP) photographs and RAF vertical photographs in an unpublished note, now in the NMRS. In 1967 a valuable series of aerial photographs of the Huntingtower sites was taken by John Dewar Studios for the Inspectorate of Ancient Monuments. Subsequently RCAHMS has photographed the area resulting in the discovery of further features.


1989 ◽  
Vol 13 (3) ◽  
pp. 107-112 ◽  
Author(s):  
James L. Smith ◽  
Shepard M. Zedaker ◽  
Richard C. Heer

Abstract A prediction system was developed that estimated pine density and hardwood competition levels in young plantations using simple measurements made on 35mm aerial photographs. The precision of the prediction system was found to be moderate to good. The use of these photo-based modelsin a decision-making situation was examined. Ground-based decisions regarding replanting, spraying for competition control, or no treatment were compared to similar decisions reached strictly from the aerial photographic measurements. Approximately 80% of all decisions agreed, and 90% of theno-treatment decisions agreed. While aerial photographs do not totally eliminate the need for field work, it is clear that photographic information can often produce reliable decisions with reduced field efforts. South. J. Appl. For. 13(3):107-112.


1965 ◽  
Vol 19 (4) ◽  
pp. 372-381 ◽  
Author(s):  
H. L. Cameron

With the advent of air photography, many problems of mapping coast lines, such as those caused by surf action and underwater obstructions, were solved, as the vertical air photo shows the exact configuration of the coast and reveals many of the shallow-water obstructions. This paper shows that aerial photographs, obtained at intervals ranging from 2 to 20 years, contain important information on long-term coastal changes, brought about by wave and current action over a period of time. Two examples of such changes, revealed by sequential aerial photography, are given. It is concluded that a program of systematic study of existing photographs and supplementary rephotography would more than justify its cost.


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