共查询到19条相似文献,搜索用时 125 毫秒
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近年来随着1∶50 000重力调查项目的开展,在复杂地形尤其是通视条件差的地区,野外重力近区地改测量难以有效开展。本次研究试验结合本溪市地区开展的1∶50 000重力调查项目进行,在研究中尝试应用1∶10 000数字地形图开展近区地形改正,并将计算结果与野外实际测量进行对比验证。试验结果表明,应用1∶10 000数字地形图开展重力近区地形改正的观测精度达到±0.018×10-5 m/s2,精度高于中国地质调查局地球物理勘查规范中1∶50 000重力调查近区地改观测精度。本次试验研究表明,使用1∶10 000数字地形图进行重力近区地形改正,可以提高精度和效率、节省野外测量成本,并在今后重力近区地改中推广应用。 相似文献
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进行国际工程建设,应用Ikonos高分辨率卫片结合外业地面测量,提取空间地理信息,修测1:10 000地形图,其方法是可靠和可行的. 相似文献
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1958-2005年祁连山老虎沟12号冰川变化特征研究 总被引:23,自引:8,他引:15
老虎沟12号冰川是祁连山最大的冰川, 面积为21.9 km2, 为极大陆型冷性复式山谷冰川. 该冰川监测开始于1958年, 1962年监测被迫终止;其后于20世纪70-80年代有过短期考察, 2005年恢复全面观测. 基于野外GPS观测, 两期1∶50 000地形图和两期1∶10 000地形图及Landsat ETM 遥感影像, 分析了过去近50 a来多时间段冰川的变化特征及其对气候变化的响应过程. 结果表明: 1957-1976年间冰川退缩约100 m, 平均退缩速率5 m·5a-1, 此后冰川归于平稳态; 1985-2005年间冰川退缩140.12 m, 退缩速率较之前(1957-1976年)提高了40.2%. 结合玉门镇气象资料分析认为, 升温幅度的增大是影响20世纪90年代中期以来老虎沟12号冰川退缩加剧的根本原因, 冰川在持续高温情景下的气候响应要敏感于低温情景. 相似文献
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通过对无人机系统的组成及特点展开具体分析,继而阐述飞行姿态、航线设计、镜头检校、自动空三与模型创建、像控点布设方案和基于立体采集的无人机航摄成图的精度控制要点,并对当前无人机航摄在丘陵地区地形图成图中的应用现状展开详细阐述,以实例分析的方式,通过精度分析,证明无人机航摄成图精度满足丘陵地区1∶2 000地形图的精度要求。 相似文献
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目前,1:5万区域地质矿产调查大部分都选择在成矿远景较好、交通方便的地区进行.不少图件都不按1:5万地形图分幅范围单测或联测,而是按成矿远景区范围测图.不仅区调队测,地质队也广泛开展1:5万区 相似文献
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Extraction and accuracy assessment of high-resolution DEM and derived orthoimages from ALOS-PRISM data over Sahel-Doukkala (Morocco) 总被引:1,自引:1,他引:0
Adnane Habib Nadia Akdim Fatima-ezzahra El Ghandour Kamal Labbassi Kourosh Khoshelham Massimo Menenti 《Earth Science Informatics》2017,10(2):197-217
In Sahel-Doukkala, which is characterized by lands of a relatively low relief, global DEMs and DEMs generated from digitizing topographic maps, have been the primary source of several multidisciplinary researches. Although these products present a great value of the conducted research, the level of the given accuracy is not sufficient enough for detailed geospatial analysis. These requirements led us to generate a high-resolution DEM as an alternative of available global DEMs or/and DEMs generated from digitizing topographic maps. In this study, we present a workflow to extract high-resolution DEM at 5 m resolution and derived orthoimages from ALOS-PRISM data over Sahel-Doukkala, through photogrammetric techniques, using a variation of GCPs obtained from topographic maps at scale 1:25,000. The accuracy of the generated products is reported according to NSSDA standards. Using ten GCPs, a PRISM-DEM with 3.88 m vertical accuracy and 11.60 m horizontal accuracy, both at 95% confidence level is obtained. This DEM will serve as base dataset for further detailed geospatial analysis and mapping applications in order to identify the relationship between surface parameters and groundwater, and also to assess and understand all factors influencing the development of karst landscapes and consequently subsurface stability in the investigated area. 相似文献
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An innovative approach in the investigation of complex landscapes for hydraulic modelling applications is the use of terrestrial laser scanner (TLS) that can lead to a high-resolution digital elevation model (DEM). Another notable factor in flood modelling is the selection of the hydrodynamic model (1D, 2D and 1D/2D), especially in complex riverine topographies, that can influence the accuracy of flood inundation area and mapping. This paper uses different types of hydraulic–hydrodynamic modelling approaches and several types of river and riparian area spatial resolution for the implementation of a sensitivity analysis for floodplain mapping and flood inundation modelling process at ungauged watersheds. Four data sets have been used for the construction of the river and riparian areas: processed and unprocessed TLS data, topographic land survey data and typical digitized contours from 1:5000-scale topographic maps. Modelling approaches combinations consist of: one-dimensional hydraulic models (HEC-RAS, MIKE 11), two-dimensional hydraulic models (MIKE 21, MIKE 21 FM) and combinations of coupled hydraulic models (MIKE 11/MIKE 21) within the MIKE FLOOD platform. Historical flood records and estimated flooded area derived from an observed extreme flash-flood event have been used in the validation process using 2 × 2 contingency tables. Flood inundation maps have been generated for each modelling approach and landscape configuration at the lower part of Xerias River reach at Volos, Greece, and compared for assessing the sensitivity of input data and model structure uncertainty. Results provided from contingency table analysis indicate the sensitivity of floodplain modelling on the DEM spatial resolution and the hydraulic modelling approach. 相似文献
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本文介绍利用微机制作1:5万地形(质)图的工艺流程,看重介绍由四张1:2.5万地形(质)图,拼制一幅1:5万地形(质)图的两种新方法。 相似文献
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It has been known that ground motion amplitude will be amplified at mountaintops; however, such topographic effects are not
included in conventional landslide hazard models. In this study, a modified procedure that considers the topographic effects
is proposed to analyze the seismic landslide hazard. The topographic effect is estimated by back analysis. First, a 3D dynamic
numerical model with irregular topography is constructed. The theoretical topographic amplification factors are derived from
the dynamic numerical model. The ground motion record is regarded as the reference motion in the plane area. By combining
the topographic amplification factors with the reference motions, the amplified acceleration time history and amplified seismic
intensity parameters are obtained. Newmark’s displacement model is chosen to perform the seismic landslide hazard analysis.
By combining the regression equation and the seismic parameter of peak ground acceleration and Arias intensity, the Newmark’s
displacement distribution is generated. Subsequently, the calculated Newmark’s displacement maps are transformed to the hazard
maps. The landslide hazard maps of the 99 Peaks region, Central Taiwan are evaluated. The actual landslide inventory maps
triggered by the 21 September 1999, Chi-Chi earthquake are compared with the calculated hazard maps. Relative to the conventional
procedure, the results show that the proposed procedures, which include the topographic effect can obtain a better result
for seismic landslide hazard analysis.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Samih B. Al Rawashdeh 《Arabian Journal of Geosciences》2013,6(12):4873-4880
The extraction of the water hydrographical pattern and watershed and subwatershed boundary is very important for many types of study. In Jordan the topographic map scale 1:25,000 produced at the Royal Jordanian Geographic Center is considered the most important source of contour lines and drainage pattern; therefore, it is imperative to estimate the accuracy of these types of data extracted from the previous topographic maps. In this project we aim to extract the hydrographical pattern of the Humrat Assahn basin in two methods: (1) an orthophoto based on aerial photographs using Socetset as photogrammetric software and (2) topographic maps at scale 1:25,000. A precise Digital Terrain Model (DTM) was built from stereoscopic aerial photographs using Socetset software. As we know, the quality of DTM is imperative to assure precise results and depends on the method of creation of this DTM besides other factors. A complete data base for the necessary information for achieving this objective was built. The obtained results were evaluated using GPS points and photo-interpretation. The results show that the drainage pattern extracted from DTM using photogrametric software was very accurate; meanwhile, the accuracy of the drainage pattern extracted from topographic maps has some flaws. 相似文献
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地形图数字化是获取矢量空间数据,建立GIS数据库的一项重要的基础工作,而地形图数字化的精度直接影响着GIS数据库的精度.地形图数字化的方式通常有两种,一是手扶跟踪数字化,另一种是扫描数字化.本文就扫描数字化的精度问题做以简单的探讨. 相似文献
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