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201.
数字地理底图是地质环境调查不可缺少的组成部分,但现有数据大多现势性较差,如何更新值得探讨。文中提出利用Google Earth进行地理底图更新的方法,并介绍了更新的步骤和精度,该方法简单快捷、可操作性较强,具有一定的实用价值。 相似文献
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Bangbo Hu 《The Professional geographer》2001,53(1):32-44
This paper explores the application of geographic information systems (GIS) in the evaluation of the accuracy of early maps through a case study of The Map of the Prefectural Capital of 1261. The evaluation of the accuracy of early maps is an important aspect of the study of the history of cartography, but no standard methodology has been generally accepted. The purpose of this paper is to assess the positional accuracy and the relative relations of the spatial objects on The Map of the Prefectural Capital using GIS. The procedure of the study includes identification of locations of the points and features of The Map of the Prefectural Capital on a modern base map, digitization of the early map and the modern base map, overlays of the digitized early map and modern base map, and an analysis of the absolute and relative distortion of the early map. The results of the analysis show that The Map of the Prefectural Capital of 1261 is reasonably accurate considering the technical ability of the thirteenth century, although it contains a considerable amount of positional displacement. In contrast to the amount of positional displacement, the relative relations among the objects are depicted much more precisely. 相似文献
204.
Leo Kristjansson Agust Gudmundsson Hreinn Haraldsson 《International Journal of Earth Sciences》1995,84(4):813-830
We have carried out stratigraphic mapping in the Upper Miocene basalt lava pile around the fjords Mjoifjördur and Seydisfjördur, eastern Iceland. The mapping is based on conventional methods including the use of interbasaltic clastic horizons and petrographically distinct lava groups. These units are also used to provide correlations with the Nordfjördur area south of Mjoifjördur. We present a 3-km composite stratigraphic column for the area between Mjoifjördur and Seydisfjördur. The geology of this area shows some differences from the classical model of Walker for the structure of eastern Iceland partly due to the fact that most of Mjoifjördur is not in the vicinity of central volcanoes. Detailed laboratory measurements of remanent magnetization were carried out on oriented core samples from 363 lavas in 10 selected profiles. The local paleomagnetic polarity stratigraphy supports correlations made on the basis of other criteria. Over 20 geomagnetic reversals are recorded in the eastern Iceland lava pile in a period approximately 13-10 Ma ago. The geomagnetic field during this period averages to a central axial dipole field, and its overall statistical properties resemble those obtained in earlier surveys in Iceland. 相似文献
205.
Mental Maps and Fuzziness in Space Preferences* 总被引:1,自引:0,他引:1
Mental maps are widely used to represent aggregate residential preferences in a population. This study examines the contention by researchers that the dominant viewpoint in a group in terms of residential desirability is not affected by the fuzziness in individual space preferences. Results indicate that a significant misrepresentation of group preferences can result when fuzziness of individual preferences is overlooked. The use of ordinal scales to generate mental maps is likely to distort the actual pattern of residential preferences that dominates in the group because of the failure of the ranking approach to account for imprecision and ambiguity in individual preferences. Because interval scales used in rating or evaluating tasks do not force individuals to give a crisp judgement of places, they are more adequate than ordinal scales for mental mapping and for behavioral analysis. 相似文献
206.
重庆城市地貌图的设计和编制 总被引:5,自引:0,他引:5
本文从设计意图、设计内容和编制方法等方面,总结了重庆城市地貌制图中取得的一些主要经验,探讨了城市地貌图的特点。 相似文献
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209.
Valiya M. Hamza Fernando J.S. Silva Dias 《Physics of the Earth and Planetary Interiors》2005,152(4):223-256
A summary of heat flow data acquired over recent years in several areas in the eastern (Brazil and Paraguay) and western (Bolivia, Chile, Colombia and Ecuador) parts of South American continent are presented. The improvements in the database have allowed numerical representations of heat flow for southeastern and central segments of the Precambrian fold belts in Brazil, Central Andean cordilleras in Chile and Bolivia, Southern Volcanic arc in Peru, Neuquén Province in southwestern Argentina, Chaco basin in Paraguay, Oriente basin in Ecuador and the system of pericratonic basins in north central Colombia. The maps reveal considerable variability in heat flow, not only between the main tectonic units but also within them. The intra-regional variations seem to originate mainly from complexities in local geologic structures while the inter-regional ones seem to point to action of deep-seated tectonic processes. The cordilleran regions are, in general, characterized by relatively high heat flow (>70 mW/m2), compared with the coastal regions to the west and the Pre-cordilleran basins to the east. In the eastern part of the continent, heat flow is low to normal (<60 mW/m2), the exceptions being the Mesozoic rift basins, areas of Cenozoic alkaline intrusions and some isolated belts of overthrust tectonics in the central parts of Brazil. There are indications that heat flow is high in the Patagonian Platform relative to that found in the Brazilian Platform.In addition, polynomial methods were employed for examining large-scale variations of heat flow over the continent. Specifically, a general-purpose least square solution was used to determine the coefficients of up to fourth order in latitude and longitude. Some of the large-scale trends seen in low order polynomial representations seem to be indicative of the nature of deep-seated heat transfer processes. The systematic increase in regional heat flow in the north-south direction is an example. It is considered as the consequence of thermal blanketing effect of the continental segment of the South American lithosphere. Trends seen in higher order polynomials seem to be associated with regional tectonic patterns and subduction-related magmatism. Prominent among these are east-west trending belts of low heat flow in northern Peru and in central Chile, as well as the high heat flow belts in northern Chile, Altiplano of Bolivia and northwestern Argentina. Limitations arising from low data density and uneven geographic distribution warrant higher degree polynomial representations. 相似文献
210.
A MODEL FOR QUANTITATIVELY ESTIMATING SHORT-RANGE PRECIPITATION BASED ON GMS DIGITALIZED CLOUD MAPS—PART Ⅱ:ASSESSMENT OF RESULTS FROM THE MODEL FOR SATELLITE-IMAGE QUANTITATIVELY ESTIMATING PRECIPITATION 下载免费PDF全文
This is Part Ⅱ of this series.It introduces the technique for recognizing MαCS phased properties and its precipitation center or centers by means of dynamic digitalized cloud maps and presents the assessment of the effectiveness of the model proposed in Part Ⅰ as to its fitting and forecasting accuracy. 相似文献