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1.
随着地理信息技术的发展,人们期望在数字地图产品的应用中能够突破以图幅为单位的管理机制,实现对数字地图产品的自动拼接和裁剪,实现对3维可视场的无级缩放和无缝漫游等功能。而要实现这些功能,基于数据库的任意区域的拼接和裁剪技术实现是其中的关键。仅针对DEM的拼接和裁剪方法进行一些粗浅的尝试,提出基于数据库的任意区域DEM拼接与裁剪的实现思路和具体过程,以及针对不规则三角网(TIN)的裁剪方法。 相似文献
2.
数字摄影测量系统(MapMatrix)能够广泛应用于低空摄影、高空摄影以及卫星遥感当中.输电线路工程覆盖范围广、地形复杂、对数字高程模型(Digital Elevation Model,DEM)精度要求高.结合具体的工程项目,利用MapMatrix软件中的DEMMatrix模块进行DEM的编辑,阐述具体操作过程中软件各功能的应用情况,进一步分析DEMMatrix模块在输电线路工程DEM编辑上的实用性.实验结果表明,利用MapMatrix能够较快、精确地完成DEM编辑工作. 相似文献
3.
利用不确定度的海底数字高程模型构建 总被引：1，自引：0，他引：1
综合考虑水深点不确定度信息和距离对格网节点的影响,提出了利用不确定度和距离联合确定权函数方法构建海底数字高程模型(DEM)。利用不确定度信息传递模型和海底DEM格网分辨率选取标准,在DEM精度和数据容量之间保持平衡,为生成多种形式、满足多种需要的海洋数字产品提供了基础。 相似文献
4.
城市地表典型遥感参数与热岛效应时空分析研究——以桂林市为例 总被引：1，自引：0，他引：1
利用桂林市1991年和2013年的卫星遥感影像数据,分别提取两个时期的归一化建筑指数(NDBI)、归一化植被指数(NDVI)和改进的归一化差异水体指数(MNDWI)3个地表典型参数,并利用回归分析方法,分析了3个地表典型参数与利用Landsat卫星(热红外波段)反演的地表温度(LST)的相关关系。研究结果表明:桂林市中、高、极高温区3个温度类别的变化趋势与桂林市城市扩张趋势基本一致;NDBI与LST成显著的正相关关系,而NDVI、MNDWI则与LST成负相关关系,且各参数对地表温度响应的程度各有差异。该研究成果对于揭示桂林市热岛效应现状、缓解热岛效应及推进桂林市生态城市建设具有一定的参考意义。 相似文献
5.
浅谈数字正射影像图制作中的镶嵌技术 总被引：5，自引：0，他引：5
本文通过使用VirtuoZo全数字工作站制作数字正射影像图，介绍数字镶嵌技术(DEM采集、拼接和数字微分纠正技术)及实际应用过程中的注意事项，并提出相应的解决方案。 相似文献
6.
7.
基于DEM的遥感数据复原方法研究 总被引：1，自引：0，他引：1
介绍了一种基于数字高程模型（DEM）的遥感数据复原新方法。此方法将地形因子作为最主要的作用因子，不考虑卫星传感过程中的随机影响。首先，根据基础地理数据，按其等高线层生成DEM； 然后，利用DEM，通过实测样点、DEM和经过纠正的遥感数据的信息融合，进行遥感数据中像元样点的坡度、坡向分析，建立DEM与遥感信息的相关关系模型，以数学统计方法描述地形因子对遥感数据的作用机理； 最后，进行逐像元的遥感信息复原(归一化)。结果表明，该方法具有较好的信息复原效果，可消除或减少地形对遥感数据的影响，增强遥感技术在山区复杂地形下的实用性。 相似文献
8.
聂荣建 《测绘与空间地理信息》2013,(1):168-170
主要介绍在基础地理信息数据库数字3D(DLG、DOM、DEM)产品生产时,如何对DLG的高程点与DEM的格网匹配情况进行质检,并基于VB编程来实现计算机检查,从而提高检查的效率和可靠性。 相似文献
9.
在DEM作业生产过程中,查询DEM成果数据文件是否上交及DEM完成进度存在效率低、费时等问题,现利用EXCEL调用VB程序实现了DEM作业进度的快速获取,有效地提高了DEM作业效率,该工具对提高其他测绘产品生产和管理效率、减少产品作业环节同样具有重要作用. 相似文献
10.
立体卫星影像在覆盖范围、重访周期、测绘产品更新速度、数据获取成本等方面较传统航空影像有着较明显的优势。WorldView-3是迄今全球空间分辨率最高的商业遥感卫星,全色波段分辨率0.31m,能获取同轨立体像对,理论上可代替传统航空影像用于大比例尺测图。本文以北京市石景山区和通州区的两个WorldView-3立体像对为数据源,确定了一整套制作1∶2000比例尺3D产品的技术流程,具体包括数字线划图(Digital Line Graphic, DLG)、数字高程模型(Digital Elevation Model, DEM)和正射影像图(Digital Orthophoto Map, DOM),验证了3D产品的精度,成图结果符合国标精度要求,并为生产作业中控制点布设方案、密集匹配算法选取等提供了参照和解决方案。 相似文献
11.
针对城市及周边区域建造区和自然地表交织分布的特点,探讨了利用归一化植被指数(NDVI)和归一化建造指数(NDBI)构造趋势面的地表温度(LST)降尺度方法,以北京市市区及周边较平坦区域为例实现了LST自960 m向120 m的降尺度转换。分析了LST空间分布特征及NDVI、NDBI对地物的指示性特征;以北京市四至六环为界分析NDVI、NDBI趋势面对地表温度的拟合程度及各自的适用区域;在120 m、240 m、480 m和960 m 4个尺度上评价了NDVI、NDBI和NDVI+NDBI趋势面对LST的拟合程度和趋势面转换函数的尺度效应;对NDVI、NDBI和NDVI NDBI等3种方法的降尺度结果分覆盖类型、分区域对比评价。实验结果表明结合两种光谱指数的NDVI NDBI方法降尺度转换精度有所改善,改善程度取决于地表覆盖类型组合。 相似文献
12.
Mangrove forests grow in intertidal zones in tropical and subtropical regions and have suffered a dramatic decline globally over the past few decades. Remote sensing data, collected at various spatial resolutions, provide an effective way to map the spatial distribution of mangrove forests over time. However, the spectral signatures of mangrove forests are significantly affected by tide levels. Therefore, mangrove forests may not be accurately mapped with remote sensing data collected during a single-tidal event, especially if not acquired at low tide. This research reports how a decision-tree −based procedure was developed to map mangrove forests using multi-tidal Landsat 5 Thematic Mapper (TM) data and a Digital Elevation Model (DEM). Three indices, including the Normalized Difference Moisture Index (NDMI), the Normalized Difference Vegetation Index (NDVI) and NDVIL·NDMIH (the multiplication of NDVIL by NDMIH, L: low tide level, H: high tide level) were used in this algorithm to differentiate mangrove forests from other land-cover and land-use types in Fangchenggang City, China. Additionally, the recent Landsat 8 OLI (Operational Land Imager) data were selected to validate the results and compare if the methodology is reliable. The results demonstrate that short-term multi-tidal remotely-sensed data better represent the unique nearshore coastal wetland habitats of mangrove forests than single-tidal data. Furthermore, multi-tidal remotely-sensed data has led to improved accuracies using two classification approaches: i.e. decision trees and the maximum likelihood classification (MLC). Since mangrove forests are typically found at low elevations, the inclusion of elevation data in the two classification procedures was tested. Given the decision-tree method does not assume strict data distribution parameters, it was able to optimize the application of multi-tidal and elevation data, resulting in higher classification accuracies of mangrove forests. When using multi-source data of differing types and distributions to map mangrove forests, a decision-tree method appears to be superior to traditional statistical classifiers. 相似文献
13.
应用面向对象的决策树模型提取橡胶林信息 总被引：4，自引：0，他引：4
橡胶林的无序和不合理种植引发了一系列的生态问题,快速监测橡胶林空间分布及动态变化,对橡胶的合理种植、区域生态环境保护以及有关部门的规划决策有重要的指导意义。以MODIS归一化植被指数NDVI时间序列数据和多时相的Landsat TM数据为基础分析橡胶林的季相和光谱特征,确定橡胶识别的关键时期和特征参数,构建面向对象的决策树分类模型,开展橡胶信息提取研究。结果表明,多时相的遥感数据可反映橡胶的季相特征,以TM数据为基础计算得到的陆表水分指数LSWI和归一化植被指数NDVI可作为橡胶识别的光谱特征参数,橡胶休眠期是利用遥感方法进行橡胶提取的最佳时期。相比于单时相数据,利用包含橡胶关键物候期的多时相遥感数据能得到更高的橡胶林提取精度。 相似文献
14.
遥感影像时—空融合可集成多源数据高空间分辨率和高时间分辨率互补优势,生成时间连续的高空间分辨率影像,在遥感影像的动态监测与时序分析等方面具有重要应用价值。然而,现有多数研究往往基于单一数据产品对时—空融合算法进行评价,而在实际生产应用中,需要验证算法在多种遥感产品数据的融合表现;此外,目前研究大多基于"单点时刻"进行评价,忽略了时—空融合在"时间线"上的有效验证。本文提出遥感影像时—空融合的"点"—"线"—"面"多角度综合质量评价策略,基于Landsat TM和MODIS影像,建立了时—空融合系列数据集,包括地表反射率、植被指数和地表温度,并在此基础上从单时相("点")、时间序列("线")、多种数据产品("面")多个角度对4种典型融合算法进行定性和定量的综合评价。结果表明,基于不同产品类型的数据集更能充分验证算法性能,且结合单点时刻和时间序列的评价更加客观。 相似文献
15.
Land use and land cover classification over a large area in Iran based on single date analysis of satellite imagery 总被引：3，自引：0，他引：3
Hossein Saadat Jan AdamowskiRobert Bonnell Forood SharifiMohammad Namdar Sasan Ale-Ebrahim 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(5):608-619
Accelerated soil erosion, high sediment yields, floods and debris flow are serious problems in many areas of Iran, and in particular in the Golestan dam watershed, which is the area that was investigated in this study. Accurate land use and land cover (LULC) maps can be effective tools to help soil erosion control efforts. The principal objective of this research was to propose a new protocol for LULC classification for large areas based on readily available ancillary information and analysis of three single date Landsat ETM+ images, and to demonstrate that successful mapping depends on more than just analysis of reflectance values. In this research, it was found that incorporating climatic and topographic conditions helped delineate what was otherwise overlapping information. This study determined that a late summer Landsat ETM+ image yields the best results with an overall accuracy of 95%, while a spring image yields the poorest accuracy (82%). A summer image yields an intermediate accuracy of 92%. In future studies where funding is limited to obtaining one image, late summer images would be most suitable for LULC mapping. The analysis as presented in this paper could also be done with satellite images taken at different times of the season. It may be, particularly for other climatic zones, that there is a better time of season for image acquisition that would present more information. 相似文献
16.
随着数字高程模型(DEM)在电力行业的广泛应用,电力地图需求部门对数字高程模型的要求越来越高。针对在数字高程模型生产中,电力业主方提供的立体模型高程基准不统一的问题,本文提出了基于特征数据的DEM基础转换方法。该方法在进行DEM制作过程中采用先采集特征数据,后转换特征数据高程基准的方式,实现了DEM成果的高程基准的转换,并进行了实验验证。结果表明,通过对比转换前后的DEM成果位置精度,验证了该方法的正确性。 相似文献
17.
Jessica D. DeWitt Timothy A. Warner Peter G. Chirico Sarah E. Bergstresser 《地理信息系统科学与遥感》2017,54(4):552-572
For areas of the world that do not have access to lidar, fine-scale digital elevation models (DEMs) can be photogrammetrically created using globally available high-spatial resolution stereo satellite imagery. The resultant DEM is best termed a digital surface model (DSM) because it includes heights of surface features. In densely vegetated conditions, this inclusion can limit its usefulness in applications requiring a bare-earth DEM. This study explores the use of techniques designed for filtering lidar point clouds to mitigate the elevation artifacts caused by above ground features, within the context of a case study of Prince William Forest Park, Virginia, USA. The influences of land cover and leaf-on vs. leaf-off conditions are investigated, and the accuracy of the raw photogrammetric DSM extracted from leaf-on imagery was between that of a lidar bare-earth DEM and the Shuttle Radar Topography Mission DEM. Although the filtered leaf-on photogrammetric DEM retains some artifacts of the vegetation canopy and may not be useful for some applications, filtering procedures significantly improved the accuracy of the modeled terrain. The accuracy of the DSM extracted in leaf-off conditions was comparable in most areas to the lidar bare-earth DEM and filtering procedures resulted in accuracy comparable of that to the lidar DEM. 相似文献
18.
Mritunjay Kumar Singh R.D. Gupta Snehmani Anshuman Bhardwaj Ashwagosha Ganju 《国际地球制图》2016,31(5):506-526
The orbital and the rational polynomial coefficients (RPC) models are the two most commonly used models to compute a three-dimensional coordinates from an image stereo-pair. But it is still confusing that with the identical user provided inputs, which one of these two models provides more accurate digital elevation model (DEM), especially for mountainous terrain. This study aimed to find out the answer by evaluating the impact of used models on the vertical accuracy of DEM extracted from Cartosat-1 stereo data. We used high-accuracy photogrammetric DEM as the reference DEM. Apart from general variations in statistics, surprisingly in a few instances, both the DEMs provided contrasting results, thus proving the significance of this study. The computed root mean square errors and linear error at 90% (LE90) were lower in case of RPC DEM for various classes of slope, aspect and land cover, thus suggesting its better relative accuracy. 相似文献
19.
作为我国首颗民用立体测绘卫星数据产品,ZY-3 DSM对于我国地学分析具有极其重要的作用。本文在顾及地貌情况前提下,选取云南省高海拔山区为试验区,辅以1∶10 000野外实测地形图DEM为参考值,将分辨率为15 m的ZY-3 DSM与90 m的SRTM DEM从高程精度和地形精度进行较为全面的数据质量比较。结果表明:ZY-3 DSM在高程精度和地形精度均有更好的表现。总体看来,ZY-3 DSM数据质量更高,具有更广泛的利用价值。 相似文献
20.
Digital elevation models (DEMs) are essential to various applications in topography, geomorphology, hydrology, and ecology. The Shuttle Radar Topographic Mission (SRTM) DEM data set is one of the most complete and most widely used DEM data sets; it provides accurate information on elevations over bare land areas. However, the accuracy of SRTM data over vegetated mountain areas is relatively low as a result of the high relief and the penetration limitation of the C-band used for obtaining global DEM products. The objective of this study is to assess the performance of SRTM DEMs and correct them over vegetated mountain areas with small-footprint airborne Light Detection and Ranging (Lidar) data, which can develop elevation products and vegetation products [e.g., vegetation height, Leaf Area Index (LAI)] of high accuracy. The assessing results show that SRTM elevations are systematically higher than those of the actual land surfaces over vegetated mountain areas. The mean difference between SRTM DEM and Lidar DEM increases with vegetation height, whereas the standard deviation of the difference increases with slope. To improve the accuracy of SRTM DEM over vegetated mountain areas, a regression model between the SRTM elevation bias and vegetation height, LAI, and slope was developed based on one control site. Without changing any coefficients, this model was proved to be applicable in all the nine study sites, which have various topography and vegetation conditions. The mean bias of the corrected SRTM DEM at the nine study sites using this model (absolute value) is 89% smaller than that of the original SRTM DEM, and the standard deviation of the corrected SRTM elevation bias is 11% smaller. 相似文献