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871.
Soile Tissari Vesa Nykänen Jouni Lerssi Mikko Kolehmainen 《Natural Resources Research》2007,16(2):159-169
Weights-of-Evidence (WofE) and Radial Basis Function Link Net (RBFLN) were applied to soil group mapping in eastern Finland.
The data consisted of low altitude airborne geophysical measurements, Landsat 5 TM-satellite image, and digital elevation
model (DEM) and slope information derived from it. Probability maps were constructed for each soil group one by one and combined
into a prediction map of soil groups using maximum posterior probability (WofE) or pattern membership (RBFLN). Self-Organizing
Map (SOM) and Sammon’s Mapping were applied for selecting the data sets for modeling and visualizing the data. The soil types
belonging to each soil group used in the Arc-SDM modeling were defined by clusters revealed by the SOM and Sammon’s Mapping
algorithms. The soil types with similar characters were collected in the same cluster. Numerical evaluation of the models’
performance was performed using the confusion matrix. The Ratio of Correct Classifications (RCC) for the best WofE model was
0.64 in the training area and 0.61 in the testing area. The RCC for the best RBFLN model was 0.62. Modeling of soil groups
using Arc-SDM is time consuming because models need to be constructed for each soil group before combining them into a final
prediction map. In this study a simple method was tested for combining the maps. In the future, more attention should be paid
to combining the posterior probability models and also to selecting data sets used for modeling. 相似文献
872.
As large destructive seismic events are not frequent in Algeria, anexhaustive knowledge of the historical seismicity is required to have arealistic view of seismic hazard in this part of the world. This research workpresents a critical reappraisal of seismicity in the north-eastern Algeria forseismotectonic and seismic hazard purposes. This part of work focuses onthe seismicity of pre-1900 period for the area under consideration[33°N-38°N, 4°E-9.5°E]. By going back tothe available documentary sources and evaluating and analysing the eventsin geographical, cultural and historical context, it has been possible toidentify 111 events, from 1850–1899, which are not reported in therecent Algerian catalogue. Several spurious events, reported in standardlistings, have been deleted and nine unknown events have been discovered.It is quite clear that macroseismic information derived from press reportsand published documents in Algeria, under certain conditions, is veryincomplete, even for destructive earthquakes, located in the countrysideaway from communication centres. One of the reasons for this iscensorship, noticeable during the colonisation period. Critical analysis ofnewly collected information has allowed the determination and/or theimprovement of the macroseismic parameters of each event, such aslocation, maximum epicentral intensity and magnitude to produce anearthquake catalogue as homogeneous and complete as the available data,for the zone under study. The criteria used in this research are explainedand eight historical earthquakes have been the subject of retrospectivemacroseismic field construction.The investigation of historical earthquakes is one of the most important taskin studying seismotectonic for seismic hazard evaluation purposes. 相似文献
873.
In recent years, the visualization of geospatial data has undergone dramatic and important developments. Next to static maps, nowadays, immersive and highly interactive virtual environments can be used to explore and present dynamic geospatial data. Additionally, the World Wide Web has developed into a prominent medium to disseminate geospatial data and maps. In visualizing geospatial data, methods and techniques from fields, such as scientific visualization and information visualization, are applied because of the large volumes of data at hand. This has accumulated in what is known as geovisualization—the use of visual geospatial displays to explore data and through that exploration to generate hypotheses, develop problem solutions and construct knowledge. Maps and other linked graphics play a key role in this process. The objective of this paper is to demonstrate the usefulness of geovisualization and, in particular, how alternative graphic representations can stimulate the visual thought process. This is demonstrated by applying geovisualization techniques to Minard's well-known map of Napoleon's 1812 campaign into Russia, the “Carte figurative des pertes successives en hommes de l'Armee Française dans la campagne de Russie 1812–1813” (http://www.itc.nl/personal/kraak/1812/). 相似文献
874.
875.
依据3DS MAX软件制作三维图的原理和方法,制作了东华理工学院三维校园图。文中详细介绍了利用3DS MAX技术制作三维图的过程.包括:从资料的收集、底图的生成、立体模型的制作、三维贴图到校园立体图的渲染输出等。对在3DS MAX环境下建筑物的建模,材质贴图,灯光设置等关键技术作了重点阐述。并就三维场景的虚拟漫游的图像文件格式、渲染的时间等技术因素的设置作了必要的论述。制作的校园立体图既具有传统鸟瞰图的特点又具有普通地图特点,所包含的信息量远比两者多,并且可利用它作地理信息系统底层数据,用于实现三维仿真及属性查询等多种用途。 相似文献
876.
桐柏-信阳一带区域地球化学调查是全国区域化探扫面的一部分.编图中涉及19和20投影带及个1:20万图幅的拼接,制图中存在不少技术难题.为了避免2个投影带产生的裂隙坐标不统一,将20带数据转换到19带,然后在高斯-克吕格座标表中查取座标自然值,并计算座标通用值后进行座标展绘,取得了较好的制图效果. 相似文献
877.
In this paper we apply a probabilistic methodology to map specific seismic hazard induced by the Vrancea Seismogenic Zone, which represents the uttermost earthquake danger to Romania as well as its surroundings. The procedure is especially suitable for the estimation of seismic hazard at an individual site, and seismic hazard maps can be created by applying it repeatedly to grid points covering larger areas. It allows the use of earthquake catalogues with incompletely reported historical and complete instrumental parts. When applying themethodology, special attention was given to the effect of hypocentral depth and the variation of attenuation according to azimuth. Hazard maps specifying a 10% chance of exceedance of the given peak ground acceleration value for an exposure time of 50 years were prepared for three different characteristic depths of earthquakes in the Vrancea area. These maps represent a new realistic contribution to the mitigation of the earthquake risk caused by the Vrancea Seismogenic Zone in terms of: (1) input data (consistent, reliable, and the most complete earthquake catalogue), (2) appropriate and specific attenuation relationships (considering both azimuthal and depth effects); and (3) a new and versatile methodology. 相似文献
878.
ROBERT R. CHURCHILL 《Geographical review》2004,94(1):1-22
ABSTRACT. City maps are among the oldest and most popular forms of cartographic representation, yet urban cartography has received only limited scholarly attention. A review of the early history of city mapping suggests a progression of representational forms from profile to perspective to plan, a progression that parallels urban growth. The history of urban mapping reflects a desire to comprehend the geography of the city for reasons of curiosity and practical necessity, but the map also may become an icon that engenders a sense of pride and belonging, if not allegiance and control. An examination of Chicago maps indicates that, in addition to evolution in representational styles, the subjects of maps change to serve demands of the moment. City maps not only constitute a rich historical archive but also are dynamic agents in urban development. The urban landscape is shaped by cartographic vision. 相似文献
879.
地图图书产品精品化战略的实施 总被引:1,自引:0,他引:1
论述了地图图书精品化的必要性以及精品地图、图书的策划和出版 ,提出了地图精品化战略的实施办法。 相似文献
880.
Predictive models for calculating sediment yield and discharge require accurate areal data. Such models may be unrealistic when using digitized data given the potential error involved in compiling and digitizing thematic polygon maps. The estimation of boundary variability for digitized polygon maps of a 0·34 km2 area of badlands in Dinosaur Provincial Park, Alberta shows the effects of positional errors introduced during mapping and digitizing processes. Polygon overlay of maps of surface features and slopes produced high frequencies of very small polygons and some unlikely combinations of slopes and surface features, and decreased reliability in areal measurements in the composite map. At an epsilon band width of 0·7 m, a reasonable estimate of boundary variability, 31·7 per cent of the resultant overlaid map can be considered unreliable. 相似文献