钻孔岩芯岩（矿）石磁化率参数特征并用于地层岩性划分     

李水平  王建光  程华  白德胜  张勇  谢彦军 《物探与化探》2013,(5)

坦桑尼亚联合共和国某金矿,在没有测井设备的情况下,利用SM-30磁化率仪,直接测定钻孔岩芯岩（矿）石的磁化率数值,将钻孔深度与该深度处对应的磁化率数值绘制成类似于测井曲线,根据磁化率参数的曲线特征,进行岩性层位划分,确定金矿层的走向,经与钻孔地质柱状图对比,该方法效果很好。  相似文献   

河南省几个中生代地层问题的讨论   总被引：1，自引：0，他引：1  

王德有 《地质论评》2013,59(4):601-606

笔者认为潭头盆地白垩系和古近系的地层序列(由下而上)应为:秋扒组、高峪沟组、潭头组、大峪组。汝阳凹陷白垩系和古近系的地层序列(由下而上)应为:九店组、下河东组、郝岭组、上东沟组、石台街组。通过岩石地层、生物地层及沉积学等方面的探讨,认为潭头盆地K—T界线目前只能认为是"平行不整合"。汝阳凹陷含恐龙等生物群的郝岭组的地质时代应为早白垩世中晚期。马市坪盆地的南召组与马市坪组的接触关系不是"假整合",而是"整合接触",其地层年代为早白垩世。  相似文献   

基于GeoSOT的遥感影像云索引模型研究     

安丰光  宋树华  罗旭  濮国梁 《地理与地理信息科学》2014,30(5)

针对目前遥感影像中云信息描述简单、云的空间分布信息不足而限制影像局部云信息检索的现状,提出了基于GeoSOT的影像云索引模型。该模型根据空间信息建立GeoSOT网格与遥感影像的对应,通过判断每个GeoSOT剖分面片对应的影像数据块是否有云,并记录剖分面片编码和判断结果,实现对遥感影像中局部云信息建立索引;在检索影像中局域云信息时,根据剖分面片编码查找云信息标识即可。同时,探讨了不同等级影像数据产品采用精确逻辑剖分和冗余逻辑剖分构建影像云索引的方法,设计了影像云索引的数据结构,分析了影像数据建立云索引的存储代价。通过仿真实验表明,对遥感影像构建基于GeoSOT剖分编码的云索引代价小,其存储量约为原数据的0.01%,提高了影像中局部云信息查询效率,为计算机自动选取高质量的影像提供了一个有效的技术途径。  相似文献   

基于AutoCAD的大比例尺地形图批量分幅关键技术研究     

李永泉  戴相喜  覃伟 《江苏测绘》2014,(3):28-29

地图分幅、整饰是大比例尺地形图数据生产过程中十分重要的环节。为提高该环节工作效率,以大比例尺地形图自动分幅、整饰为目标,设计了技术流程,并解决了该过程中几项关键技术,提高了该工作的工作效率。  相似文献   

Optimizing landslide susceptibility mapping in the Kongtong District,NW China: comparing the subdivision criteria of factors     

Ge Yan  Xiangang Gui  Yu Xie  Hongliang Zhao 《国际地球制图》2013,28(13):1408-1426

Abstract

The standards applied to reclassify landslide-conditioning factors differ among studies and may change the accuracy of identifying landslide-prone areas. Therefore, we identified two standards per factor (elevation, aspect, slope, proximity to roads and proximity to streams) from the existing literature and set them as predisposing criteria in this paper. In addition to the five factors, lithology represented by types and a landslide inventory map produced from field surveys were also used in mapping. Thirty-two landslide susceptibility maps were generated based on weights-of-evidence and evaluated using the relative operative characteristic method. The results show that the subdivision criteria of factors change the accuracy, with the success rate varying from 84.34% to 87.51%. The map with the highest value captures more landslides in relatively higher susceptibility classes and is therefore considered the optimal one. Ultimately, a simplified mode of combining subdivision criteria is proposed to simplify comparison.  相似文献   

The NHDPlus dataset,watershed subdivision and SWAT model performance     

Li-Chi Chiang 《水文科学杂志》2013,58(10):1690-1708

Abstract

The Soil and Water Assessment Tool (SWAT) has been developed to evaluate the effectiveness of agricultural management practices on watershed water quality. Many studies have indicated that watershed subdivision can affect the accuracy of model predictions. Most of them used the minimum drainage area (MDA) to delineate sub-watersheds, and varied the value of MDA depending on the size of the watershed being modelled. Instead of MDA, we use the National Hydrography Dataset Plus (NHDPlus)—an integration of the best features of the National Hydrography Dataset (NHD), Watershed Boundary Dataset (WBD), National Elevation Dataset (NED), and the National Land Cover Dataset (NLCD)—to delineate the watershed. The Kaskaskia River watershed in Illinois, USA, was selected to investigate the individual effects of sub-watershed and hydrologic response unit (HRU) delineations on predicted streamflow, total suspended sediment (TSS) and total nitrogen (TN) losses at two USGS gauges. In addition, an MDA of 3000 ha, and four levels of stream (the 2nd, 3rd, 4th and 5th order) were evaluated. Three levels of HRU threshold (5%, 10% and 15%) were used for each stream order model. The results show that stream order had little effect on predicted streamflow, but a great impact on TSS and TN losses, and the impact of HRU delineation became greater when a higher stream order was used to delineate the watershed. For higher stream order, fewer streams were recognized in SWAT simulations, which resulted in less sediment routing and channel processes, which, in turn, led to less deposition in the channels; thus high sediment losses were obtained at the watershed outlet. However, fewer channel processes led to less in-stream N processes; thus lower TN losses. Overall, the SWAT simulations performed the best when the 2nd stream order was used for delineations comparing with USGS observed data, followed by the 3rd stream order. Therefore, to fully depict the watershed characteristics to perform SWAT simulations, a stream order higher than 3rd order is not recommended for watershed delineation.