共查询到18条相似文献，搜索用时 93 毫秒
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利用南流江流域30 m分辨率的DEM数据,介绍了Arc GIS中进行河网提取的一系列过程,并利用其图解建模工具,提取南流江流域的不同汇流累积面积的水系河网,实现了提取过程的流程化处理。分别统计河源密度和沟壑密度,并分别计算它们与汇流累积面积的几何函数关系,并对其进行二阶求导,确定其二阶导数关系,得到合适的汇流累积阈值,并借助分形分维理论对河网的分维值进行了验证。利用函数关系和分形分维确定汇流累积面积提取水系河网的方法有效地避免了人工选择汇流累积面积的主观性,提高了研究结果的准确性和可靠性,在知道研究流域河网分维值的前提下,可快速获取准确的汇流累计面积阈值。 相似文献
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拉林河流域水系分维研究 总被引：2，自引：0，他引：2
针对传统方法在水系分维估算中对集水面积阈值的确定主观性和不确定性较强,同时传统的数盒子等分维估算方法存在计算强度大、工作效率低、数据结果不客观等问题,该文基于SRTM DEM数据,运用ArcGIS软件对拉林河流域自动提取河网水系图;对水系进行不同集水面积阈值下的分维值计算,利用趋势线、相关系数检验等方法对拉林河流域集水面积阈值进行估算;并将提取出的集水面积阈值与实际测绘地形图进行对比,发现利用该方法确定阈值得到的水系与实际水系较为一致。同时,基于GIS的分维研究与传统的数盒子等方法计算水系维数相比,具有客观、经济、高效的优势。最后根据集水面积阈值与水系分维的相互关系,得出该流域水系分维值为1.28,说明拉林河流域尚处于侵蚀发育阶段的幼年期,发育受地质条件影响较大。 相似文献
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基于 DEM 对喀斯特地貌山地及水系信息的提取--以桂林阳朔县为例 总被引：1，自引：0，他引：1
以30 m分辨率的SRTM－DEM数据为基础,通过GIS的空间分析功能,首先对数据进行坡度分析,通过坡度分级法将山地与平原划分,自动提取出山地的信息,再运用碎斑处理结合TM影像对结果进行修正;其次,在ArcGIS的水文分析（ Hydrology）模块下对 DEM进行数字地形分析,提取流域特征。经分析得到了研究区域的山地及河网特征信息,并与实际地形及河流水系大致吻合,改进了传统手工和野外调查为主的提取方法,初步实现了山地、水系信息的自动提取,为研究区域社会经济更好更快地发展具有一定的参考意义。 相似文献
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以浙江省瓯江流域为例,基于SWBD修复的SRTM DEM数据,采用Arc Hydro Tools水文分析工具自动提取瓯江水系,并分地貌、分河流等级地定量评价水系数据精度,开展1∶250 000水系自动更新的可行性研究。结果表明：①SWBD修复的SRTM DEM的空白区域面积为54.78 km2,有效地弥补了SRTM DEM的数据缺失,进而提高了水系提取的准确度和精度;②与1∶250 000水系数据相比,基于SWBD修复后的SRTM DEM,在小起伏山、中起伏低山、低海拔丘陵上提取的水系数据精度高于其他地貌,而干流、一级支流、二级支流的精度又高于三级支流;③以资源三号卫星ZY-3遥感影像为参照,从水系上采集同名点反复比较点位精度后发现,利用SRTM DEM提取的水系符合制图规范和测绘内业规范（限差1 mm）,可以满足1∶250 000水系自动更新的要求。 相似文献
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汪琳 《测绘与空间地理信息》2021,44(7):134-136,143
在分析SRTM、ASTER GDEM数据源基本特征的基础上,融合了一种直接面向河网提取的数据——SRTM-ASTER,利用SRTM数据较高的垂直分辨率修正ASTER GDEM,弥补了SRTM水平分辨率上的不足;引入Landsat-8遥感卫星数据提取真实河网,分析在有(无)河网辅助条件下融合数据的提取效果,并以总长度、支流数目、套合差为特征指标进行分析.研究结果表明:1)SRTM-ASTER数据提取的河网能综合SRTM和ASTER GDEM数据的优势,提取精度较好,但河流长度以及支流数目有所减少;2)有河网辅助的条件下,经过AGREE算法进行河网纠正以后,提取结果的精度有显著提高. 相似文献
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以通化地区为试验区,利用Arc/Info软件,将原始的SRTM数据生成等高线,再插值生成不同分辨率的DEM数据,提取了高程差、坡度、坡向、地形阴影数字地形信息,并根据D8算法,对流域信息进行提取。结果表明:不同分辨率的DEM在描述地形的整体变化上存在的差异很小,但高分辨率的DEM可以更好地反映出地形的细微变化;在水文模拟方面,流域网络的数量及沟壑密度与DEM的分辨率成正相关的关系,但由于高分辨率的DEM信息冗余,在水文模拟方面,提取流域网络的时候会出现生成伪沟谷的现象。 相似文献
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Digital elevation model (DEM) data of Shuttle Radar Topography Mission (SRTM) are distributed at a horizontal resolution of 90 m (30 m only for US) for the world, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) DEM data provide 30 m horizontal resolution, while CARTOSAT-1 (IRS-P5) gives 2.6 m horizontal resolution for global coverage. SRTM and ASTER data are available freely but 2.6 m CARTOSAT-1 data are costly. Hence, through this study, we found out a horizontal accuracy for selected ground control points (GCPs) from SRTM and ASTER with respect to CARTOSAT-1 DEM to implement this result (observed from horizontal accuracy) for those areas where the 2.6-m horizontal resolution data are not available. In addition to this, the present study helps in providing a benchmark against which the future DEM products (with horizontal resolution less than CARTOSAT-1) with respect to CARTOSAT-1 DEM can be evaluated. The original SRTM image contained voids that were represented digitally as ?140; such voids were initially filled using the measured values of elevation for obtaining accurate DEM. Horizontal accuracy analysis between SRTM- and ASTER-derived DEMs with respect to CARTOSAT-1 (IRS-P5) DEM allowed a qualitative assessment of the horizontal component of the error, and the appropriable statistical measures were used to estimate their horizontal accuracies. The horizontal accuracy for ASTER and SRTM DEM with respect to CARTOSAT-1 were evaluated using the root mean square error (RMSE) and relative root mean square error (R-RMSE). The results from this study revealed that the average RMSE of 20 selected GCPs was 2.17 for SRTM and 2.817 for ASTER, which are also validated using R-RMSE test which proves that SRTM data have good horizontal accuracy than ASTER with respect to CARTOSAT-1 because the average R-RMSE of 20 GCPs was 3.7 × 10?4 and 5.3 × 10?4 for SRTM and ASTER, respectively. 相似文献
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Validation of Indian National DEM from Cartosat-1 Data 总被引：1，自引：0，他引：1
S. Muralikrishnan Abhijit Pillai B. Narender Shashivardhan Reddy V. Raghu Venkataraman V. K. Dadhwal 《Journal of the Indian Society of Remote Sensing》2013,41(1):1-13
CartoDEM is an Indian National DEM generated from Cartosat-1 stereo data. Cartosat-1, launched in May, 2005, is an along track (aft ?5°, Fore +26°) stereo with 2.5 m GSD, give base-height ratio of 0.63 with 27 km swath. The operational procedure of DEM generation comprises stereo strip triangulation of 500?×?27 km segment with 10 m posting along with 2.5 m resolution ortho image and free—access posting of 30 m has been made available (bhuvan.nrsc.gov.in). A multi approach evaluation of CartoDEM comprising (a) absolute accuracy with respect to ground control points for two sites namely Jagatsinghpur -flat and Dharamshala- hilly; second site i.e. Alwar-plain and hilly with high resolution aerial DEM, (b) relative difference between SRTM and ASTERDEM (c) absolute accuracy with ICESat GLAS for two sites namely Jagatsinghpur-plain and Netravathi river, Western Ghats-hilly (d) relative comparison of drainage delineation with respect to ASTERDEM is reported here. The absolute height accuracy in flat terrain was 4.7 m with horizontal accuracy of 7.3 m, while in hilly terrain it was 7 m height with a horizontal accuracy of 14 m. While comparison with ICESat GLAS data absolute height difference of plain and hilly was 5.2 m and 7.9 m respectively. When compared to SRTM over Indian landmass, 90 % of pixels reported were within ±8 m difference. The drainage delineation shows better accuracy and clear demarcation of catchment ridgeline and more reliable flow-path prediction in comparison with ASTER. The results qualify Indian DEM for using it operationally which is equivalent and better than the other publicly available DEMs like SRTM and ASTERDEM. 相似文献
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K. H. V. Durga Rao V. Bhanumurthy P. S. Roy 《Journal of the Indian Society of Remote Sensing》2009,37(4):587-600
Hydrological modelling of large river catchments is a challenging task for water resources engineers due to its complexity
in collecting and handling of both spatial and non-spatial data such as rainfall, gauge discharges, and topographic parameters.
In this paper an attempt has been made to use satellite-based rainfall products such as Climatic Prediction Centre (CPC)-National
Oceanic and Atmospheric Administration (NOAA) data for hydrological modelling of larger catchment where the limited field
rainfall data is available. Digital Elevation Models (DEM) such as Global DEM (1 km resolution) and Shuttle Radar Topography
Mission (SRTM) 3-arc second (90 m resolution) DEM have been used to extract topographic parameters of the basin for hydrological
modelling of the study area. Various popular distributed models have been used in this study for computing excess rainfall,
direct runoff from each sub-basin, and flow routing to the main outlet. The Brahmaputra basin, which is very complex both
hydraulically and hydrologically due to its shape, size, and geographical location, has been examined as study area in this
study. A landuse map derived from the satellite remote sensing data in conjunction with DEM and soil textural maps have been
used to derive various basin and channel characteristics such as each sub-basin and channel slope, roughness coefficients,
lag-time. Percentage of residual flows computed between observed flows and simulated flows using Global and SRTM DEMs are
discussed. It is found that the topographic parameters computed using SRTM DEM could improve the model accuracy in computing
flood hydrograph. Need of using better resolution satellite data products and the use of high-density field discharge observations
is discussed. 相似文献
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The drainage network of a sixth-order tropical river basin, viz. Ithikkara river basin, was extracted from different sources such as Survey of India topographic maps (1: 50,000; TOPO) and digital elevation data of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) (30 m) and Shuttle Radar Topography Mapping Mission (SRTM) (90 m). Basin morphometric attributes were estimated to evaluate the accuracy of the digital elevation model (DEM)-derived drainage networks for hydrologic applications as well as terrain characterization. The stream networks derived from ASTER and SRTM DEMs show significant agreement (with slight overestimation of lower order streams) with that of TOPO. The study suggests that SRTM (despite the coarser spatial resolution) provides better results, in drainage delineation and basin morphometry, compared to ASTER. Further, the variability of basin morphometry among the data sources might be attributed to spatial variation of elevation, raster grid size and vertical accuracy of the DEMs as well as incapability of the surface hydrologic analysis functions in the GIS platform. 相似文献
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为探究ASTER GDEMV3、SRTM1 DEM和AW3D30 DEM 3种开源DEM数据的高程精度,本文以高精度ICESat-2 ATLAS测高数据为参考数据,利用GIS统计分析、误差相关分析及数理统计对DEM的高程精度进行对比评价。结果表明：①AW3D30的质量最稳定;SRTM1 DEM在平原精度最高;在高原山地精度由高到低依次为AW3D30 DEM、ASTER GDEMV3、SRTM1 DEM。②DEM数据高程精度受地表覆盖影响较大,且与地形因素密切相关,在相同地表覆盖的两个研究区中DEM数据高程精度表现情况不一致,SRTM在平原地表覆盖下精度表现最好,平均误差为3.15 m,AW3D30 DEM在山地地表覆盖下精度表现最好,平均误差为7.61 m。③坡度对DEM数据的高程精度影响较大,在两个研究区3种DEM数据的高程误差均随坡度的增加而增加;坡向对DEM数据的高程精度影响较小,未发现明显的规律。 相似文献
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黄朝安 《测绘与空间地理信息》2011,34(4):110-112
SRTM全球数字高程模型数据目前已被广泛应用于多个领域。最新版本的SRTM DEM仍然存在较小的高程空值区域（数据空洞）和模糊区域。文章在模拟某试验区域SRTM DEM数据空洞的基础上,利用线性插值、反距离权插值、二次多项式插值、三次样条插值等DEM插值方法进行了数据空洞的插值填补试验和对比分析,结果表明在丘陵地区和空... 相似文献
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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
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S. Patro C. Chatterjee S. Mohanty R. Singh N. S. Raghuwanshi 《Journal of the Indian Society of Remote Sensing》2009,37(1):107-118
A coupled 1D-2D hydrodynamic model, MIKE FLOOD was used to simulate the flood inundation extent and flooding depth in the
delta region of Mahanadi River basin in India. Initially, the 1D model MIKE 11 was calibrated using river water level and
discharge data of various gauging sites for the monsoon period (June to October) of the year 2002. Subsequently, the calibrated
set up was validated using both discharge and water level data for the same period of the year 2001. The performance of calibration
and validation results of MIKE 11 were evaluated using different performance indices. A bathymetry of the study area with
a spatial resolution of 90m was prepared from SRTM DEM and provided as an input to the 2D model, MIKE 21. MIKE 11 and MIKE
21 models were then coupled using lateral links to form the MIKE FLOOD model set up for simulating the two dimensional flood
inundations in the study area. Flood inundation is simulated for the year 2001 and the maximum flood inundation extent simulated
by the model was compared with the corresponding actual inundated area obtained from IRS-1D WiFS image. 相似文献