4,077 research outputs found

    The Glacier Complexes of the Mountain Massifs of the North-West of Inner Asia and their Dynamics

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    The subject of this paper is the glaciation of the mountain massifs Mongun-Taiga, Tavan-Boghd-Ola, Turgeni- Nuru, and Harhira-Nuru. The glaciation is represented mostly by small forms that sometimes form a single complex of domeshaped peaks. According to the authors, the modern glaciated area of the mountain massifs is 21.2 km2 (Tavan-Boghd-Ola), 20.3 km2 (Mongun-Taiga), 42 km2 (Turgeni- Nuru), and 33.1 km2 (Harhira-Nuru). The area of the glaciers has been shrinking since the mid 1960’s. In 1995–2008, the rate of reduction of the glaciers’ area has grown considerably: valley glaciers were rapidly degrading and splitting; accumulation of morainic material in the lower parts of the glaciers accelerated. Small glaciers transformed into snowfields and rock glaciers. There has been also a degradation of the highest parts of the glaciers and the collapse of the glacial complexes with a single zone of accumulation into isolated from each other glaciers. Reduced snow cover area has led to a rise in the firn line and the disintegration of a common accumulation area of the glacial complex. In the of the Mongun-Taiga massif, in 1995– 2008, the firn line rose by 200–300 m. The reduction of the glaciers significantly lagged behind the change in the position of the accumulation area boundary. In the past two years, there has been a significant recovery of the glaciers that could eventually lead to their slower degradation or stabilization of the glaciers in the study area

    The nautical atlases of Alī al-sharafī

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    The two extant atlases of the 16th-century Tunisian chartmaker and scholar Alī al-Sharafī are indispensable documents for understanding the history and development of Maghrebi nautical cartography. They provide precious information on al-Sharafī’s chartmaking techniques, production and sources, which include the output of his own family and the atlas of a certain A¬mad al-Andalusī who had settled in Istanbul. The making, contents and characteristics of the atlases are examined in connection with the Maghrebi and Majorcan traditions of nautical cartography which positively influenced al-Sharafī’s compilation of coastal place names. This is explained by the circulation of such cartography across the Mediterranean of his time. Further questions are also raised on the working conditions in which Maghrebi and Andalusian chartmakers flourished and the impact of their legacy

    Creation of regions for dialect features using a cellular automaton

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    An issue in dialect research has been how to make generalizations from survey data about where some dialect feature might be found. Pre-computational methods included drawing isoglosses or using shadings to indicate areas where an analyst expected a feature to be found. The use of computers allowed for faster plotting of locations where any given feature had been e¬licited, and also allowed for the use of statistical techniques from technical geography to estimate regions where particular features might be found. However, using the computer did not make the analysis less subjective than isoglosses, and statistical methods from technical geography have turned out to be limited in use. We have prepared a cellular automaton (CA) for use with data collected for the Linguistic Atlas Project that can address the problems involved in this type of data visualization. The CA plots the locations where survey data was elicited, and then through the application of rules creates an estimate of the spatial distributions of selected features. The application of simple rules allows the CA to create objective and reproducible estimates based on the data it was given, without the use of statistical methods

    Special Libraries, May-June 1974

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    Volume 65, Issue 5-6https://scholarworks.sjsu.edu/sla_sl_1974/1004/thumbnail.jp

    The State of the Art in Cartograms

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    Cartograms combine statistical and geographical information in thematic maps, where areas of geographical regions (e.g., countries, states) are scaled in proportion to some statistic (e.g., population, income). Cartograms make it possible to gain insight into patterns and trends in the world around us and have been very popular visualizations for geo-referenced data for over a century. This work surveys cartogram research in visualization, cartography and geometry, covering a broad spectrum of different cartogram types: from the traditional rectangular and table cartograms, to Dorling and diffusion cartograms. A particular focus is the study of the major cartogram dimensions: statistical accuracy, geographical accuracy, and topological accuracy. We review the history of cartograms, describe the algorithms for generating them, and consider task taxonomies. We also review quantitative and qualitative evaluations, and we use these to arrive at design guidelines and research challenges
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