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141.
142.
SPOT-5影像的高分辨率和高信息量的性质,使其得到了广泛的应用,特别是在全国第二次土地利用调查中得到了更加深入的应用。而数字正射影像的制作是SPOT-5遥感影像应用的关键所在。本文在介绍DOM制作的基础上,依据当前获取GCP主要的三种途径采用ERDAS遥感图像处理软件进行了实验,并对最终的结果精度进行分析,总结了DOM制作过程的相关问题。 相似文献
143.
GIS技术在旅游业中的应用——兼谈旅游地理信息系统及其研究进展与展望 总被引:1,自引:0,他引:1
刘德辉 《测绘与空间地理信息》2008,31(1):90-92
本文对地理信息系统的组成与功能做了简单的概述,在此基础上介绍了GIS在旅游业发展中的主要作用及应用现状,并就旅游地理信息系统的结构与功能及其研究进展和发展趋势做了探讨。 相似文献
144.
连续运行GPS定位服务系统的探讨 总被引:1,自引:0,他引:1
朱国峰 《测绘与空间地理信息》2008,31(2):108-110
介绍了连续运行GPS定位服务的概念、实现模式及其在测绘行业中的应用。 相似文献
145.
Heinz Schneider Marco Schwab Fritz Schlunegger 《International Journal of Earth Sciences》2008,97(1):179-192
This paper uses the results of landscape evolution models and morphometric data from the Andes of northern Peru and the eastern
Swiss Alps to illustrate how the ratio between sediment transport on hillslopes and in channels influences landscape and channel
network morphologies and dynamics. The headwaters of fluvial- and debris-flow-dominated systems (channelized processes) are
characterized by rough, high-relief, highly incised surfaces which contain a dense and hence a closely spaced channel network.
Also, these systems tend to respond rapidly to modifications in external forcing (e.g., rock uplift and/or precipitation).
This is the case because the high channel density results in a high bulk diffusivity. In contrast, headwaters where landsliding
is an important sediment source are characterized by a low channel density and by rather straight and unstable channels. In
addition, the topographies are generally smooth. The low channel density then results in a relatively low bulk diffusivity.
As a consequence, response times are greater in headwaters of landslide-dominated systems than in highly dissected drainages.
The Peruvian and Swiss case studies show how regional differences in climate and the litho-tectonic architecture potentially
exert contrasting controls on the relative importance of channelized versus hillslope processes and thus on the overall geomorphometry.
Specifically, the Peruvian example illustrates to what extent the storminess of climate has influenced production and transport
of sediment on hillslopes and in channels, and how these differences are seen in the morphometry of the landscape. The Swiss
example shows how the bedding orientation of the bedrock drives channelized and hillslope processes to contrasting extents,
and how these differences are mirrored in the landscape.
An erratum to this article can be found at 相似文献
146.
Large-scale ancient landslides of the area of more than 5 km2 and volume exceeding 200 × 106 m3 are characteristic features of the valleys incised in the northern periphery of the Crimean Mountains (Ukraine). The largely
affected area is located in the outermost cuesta range of the Crimean Mountains which consists of rigid Sarmatian limestones
overlying weak Middle Miocene and Upper Palaeogene deposits. A giant landslide arose in the Alma water gap as a reflection
of several coincident preparatory factors such as suitable bedrock stratification, smectite-rich bedrock exposed to swelling
activity, presence of faults parallel to the valley trend, and river capture event which preceded the landslide event. The
occurrence of such ancient megaslides is particularly interesting in the area which is characterized by low precipitation
(<500 mm/year) and weak contemporary seismicity. It probably reflects a more dynamic environment in humid phases of the Holocene;
however, seismic triggering along the Mesozoic suture zone cannot be rejected. Compressional features such as gravitational
folds in the central and distal parts of the landslide, which probably correlate with the whole landslide genesis or its significant
reactivation, arose, according to the radiocarbon dating, during the Holocene climatic optimum in the Atlantic period. The
slope deformation has been relatively quiescent since that time, except minor historic reactivization which took place in
the frontal part of the landslide. We suppose that the studied landslide could be classified as a transitional type of slope
deformation with some signs of spreading and translational block slides. 相似文献
147.
148.
149.
吉林省中部农业土壤中滴滴涕的残留特征 总被引:3,自引:0,他引:3
通过分析研究吉林省中部农业土壤中DDT的含量和组成,探讨了该区土壤中DDT的残留特征及其可能的生态风险。研究结果表明,吉林省中部农业土壤中普遍残留DDT,质量分数为0.384~54.159μg/kg,残留水平较低,土壤DDT同系物中以p,p’-DDT和p,p-’DDE为主。DDT的组成表明,土壤中DDT主要是过去输入环境的DDT及其降解产物,但近期仍有少量的DDT输入。生态风险评估则显示该区土壤中的DDT具有一定的生态风险,应予以重视。 相似文献
150.
At present, researches on climate change of the Heihe River basin mainly focus on the relationship between basin climate change
and regional water resources, regional desertification and dynamic climatic seasons of sandstorm, but less on climate change
of oasis region, where there are more intense and frequent human activities. Based on data of precipitation, temperature,
strong wind and dust events frequencies obtained from the six meteorological stations of Zhangye region in Heihe River basin,
the features of climate change during 1968–2005 were carefully studied. Results show that the regional temperature rise rate
exceeded the average level of China. The annual precipitation changed a little, but the precipitation had a slowly increasing
trend in spring and winter. Frequencies of strong wind and sandstorm days show obviously descending trends, which had a close
correlation with the regional temperature rise and the precipitation increase in spring and winter. Meanwhile, further human
economic activities and exploitations to the oasis in the inland valley of arid regions also affected the climate change of
this region, which has a sensitive and fragile eco-environment.
__________
Translated from Journal of Desert Research, 2007, 27(6): 1048–1054 [译自: 中国沙漠] 相似文献