共查询到20条相似文献，搜索用时 31 毫秒
1.
DOM与DEM数据的管理和三维可视化 总被引：6，自引：0，他引：6
为了统一管理数字正射影像 (DOM)和数字高程模型 (DEM)数据 ,提出建立一个实用系统 ,该系统基于数据库技术统一管理海量的 DOM和 DEM数据。为了达到充分利用 DOM和 DEM数据的目的 ,在该系统中实现了DOM和 DEM数据叠加二维浏览、自动生成等高线、生成三维景观图、数字正射影像地形图、三维景观地形图等功能 相似文献
2.
等高线高程自动标注算法的研究 总被引：1，自引：0，他引：1
随着数字测图时代的来临,传统纸质图上的等高线逐渐被数字化形式的等高线图(层)所取代,数字等高线的生成与处理已成为了GIS中的一个研究的热点,然而数字等高线高程自动标注算法的人性化仍是一个有待解决的问题。本文依据人们的读图习惯进行了标注的位置和密度研究,提出了一种新的等高线高程自动算法。实验证明,该算法的结果已基本满足人们的读图习惯。 相似文献
3.
The use of remote sensing data with other ancillary data in a geographic information system (GIS) environment is useful to delineate groundwater potential zonation map of Ken–Betwa river linking area of Bundelkhand. Various themes of information such as geomorphology, land use/land cover, lineament extracted from digital processing of Landsat (ETM+) satellite data of the year 2005 and drainage map were extracted from survey of India topographic sheets, and elevation, slope data were generated from shuttle radar topography mission (SRTM) digital elevation model (DEM). These themes were overlaid to generate groundwater potential zonation (GWPZ) map of the area. The final map of the area shows different zones of groundwater prospects, viz., good (5.22% of the area), moderate (65.83% of the area) poor (15.31% of the area) and very poor (13.64% of area). 相似文献
4.
利用CASS从煤矿已有数字地形图上提取矿区地表塌陷前的高程数据,并在CASS中进行插值加密,利用开采沉陷预计程序对插值加密后的高程数据进行下沉修正计算,生成了塌陷后的矿区地表高程数据,利用该数据在CASS中通过简单的数据处理实现了煤矿塌陷区数字地形图的预计更新。该方法对煤矿生产单位的测绘工作以及开采沉陷防灾减灾工程的设计具有实际意义。 相似文献
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《制图学和地理信息科学》2013,40(1):95-104
Depending on scale, topographic maps depicting the shape of the land surfaces of the Earth are produced from different data sources. National topographic maps at a scale of 1:25 000 (25K maps) produced by General Command of Mapping are used as the base map set in Turkey. This map set, which consists of approximately 5500 sheets, covers the whole country and is produced using photogrammetric methods. Digital Elevation Models (DEMs) created from these maps are also available. Recently, another data source, Synthetic Aperture Radar (SAR) interferometric data, has become more important than those produced by conventional methods. The Shuttle Radar Topography Mission (SRTM) contains elevation data with 3 arc-second resolution and 16 m absolute height error (90 percent confidence level). These data are freely available via the Internet for approximately 80 percent of the Earth's land mass. In this study, SRTM DEM was compared with DEM derived from 25K topographic maps for different parts of Turkey. The study areas, each covering four neighboring 25K maps, and having an area of approximately 600 km2, were chosen to represent various terrain characteristics. For the comparison, DEMs created from the 25K maps were obtained and organized as files for each map sheet in vector format, containing the digitized contour lines. From these data, DEMs in the resolution of 3 arc-second were created (25K-DEM), in the same structure as the SRTM DEM, allowing the 25K-DEMs and the SRTM DEM to be compared directly. The results show that the agreement of SRTM DEM to the 25K-DEM is within about 13 m, which is less than the SRTM's targeted error of 16 m. The spatial distribution of the height differences between SRTM-DEM and the 25K-DEM and correlation analysis show that the differences were mainly related to the topography of the test areas. In some areas, local height shifts were determined. 相似文献
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针对高线图中陡坡区域特征的自动识别问题,在应用Delaunay三角网与线性插值法生成等高线图的基础上,改进了基于最大角原则生成约束Delaunay三角网的算法,对等高线图进行了三角剖分,根据等高线之间约束三角形的几何参数,计算了等高线图坡面单元坡度,识别出坡度较高区域。进一步地,给出了一种扩张算法对相连陡坡单元进行划分形成陡坡区域,计算了各个陡坡区域中心坐标、面积与平均坡度。通过对12组有256个坐标高程值的数据构建约束D-TIN并生成三维地形图对识别结果进行了评价,识别正确率达0.903,平均识别时间为33ms。实验表明,对于不同数据生成的不同等级等高线图的识别结果均有较高的效率与准确率。 相似文献
7.
A Comparison Between Contour Elevation Data Sources for DEM Creation and Soil Carbon Prediction, Coshocton, Ohio 总被引：1，自引：0，他引：1
A raster and vector GIS was created for the North Appalachian Experimental Watershed (NAEW) from legacy (1960) 1:2,400‐scale contour maps. The intent of the study was to use terrain data for the spatial modeling of soil organic carbon. It was hypothesized that DEMs derived from these data would be more accurate and therefore more useful for terrain‐based soil modeling than those from USGS 1:24,000‐scale contour data. Central tasks for this study were to digitally capture the 1:2,400‐scale maps, convert digital contour data sources to raster DEMs at multiple resolutions, and derive terrain attributes. A flexible approach was adopted, using software outside of mainstream GIS sources where scientifically or practically advantageous. Elevation contours and streamlines were converted to raster DEMs using ANUDEM. DEMs ranging in resolution from 0.5–30 m were tested for accuracy against precision carrier‐phase GPS data. The residual standard deviation was 1.68 meters for the USGS DEM and 0.36 meters for the NAEW DEM. The optimal horizontal resolution for the NAEW DEM was 5 m and for the USGS 10 m. Five and 10 m resolution DEMs from both data sources were tested for carbon prediction. Multiple terrain parameters were derived as proxies for surficial processes. Soil samples (n = 184) were collected on four zero‐order watersheds (conventional tillage, no‐till, hay and pasture). Multiple least squares regressions (m.l.s.) were used to predict mass C (kg m?2, 30 cm depth) from topographic information. Model residuals were not spatially autocorrelated. Statistically significant topographic parameters were attained most consistently from the 5 m NAEW DEM. However, topography was not a strong predictor of carbon for these watersheds, with r2 ranging from 0.23 to 0.58. 相似文献
8.
This study reports results from evaluation of the quality of digital elevation model (DEM) from four sources viz. topographic map (1:50,000), Shuttle Radar Topographic Mission (SRTM) (90 m), optical stereo pair from ASTER (15 m) and CARTOSAT (2.5 m) and their use in derivation of hydrological response units (HRUs) in Sitla Rao watershed (North India). The HRUs were derived using water storage capacity and slope to produce surface runoff zones. The DEMs were evaluated on elevation accuracy and representation of morphometric features. The DEM derived from optical stereo pairs (ASTER and CARTOSAT) provided higher vertical accuracies than the SRTM and topographic map-based DEM. The SRTM with a coarse resolution of 90 m provided vertical accuracy but better morphometry compared to topographic map. The HRU maps derived from the fine resolution DEM (ASTER and CARTOSAT) were more detailed but did not provide much advantage for hydrological studies at the scale of Sitla Rao watershed (5800 ha). 相似文献
9.
当对一个较大测区用全站仪或摄影测量方法测绘某种比例尺地形图时,可获得数量较多的地形图。对获取的数字地形图进行精度评定,是质量检查中的一个重要环节,而且工作量较大。AutoCAD为平台开发的测图软件在测绘行业十分流行,测绘行业生产的数字地图一般都能转化为DWG格式。对于DWG格式的地形图,在AutoCAD打开的图上拾取若干地物点,并把这些点的坐标自动形成一个坐标文件,与外业测量仪器RTK采集相应点形成的坐标文件,通过精度评定程序进行同名点号的坐标值对比,获得数字地形图数学精度,大大提高了数字地图精度检测工作的效率。 相似文献
10.
Motti Zohar 《制图学和地理信息科学》2013,40(6):532-546
ABSTRACTAt the beginning of the twentieth century, a British mapping team led by Captain S. F. Newcombe surveyed and mapped the Negev region, Sinai, and western Jordan. The map was mainly produced for military use. Consequently, it included a network of branched routes, water supplies and facilities, and topographic contours. This study used this map to examine the development of routes in the Negev region between the beginning of and until the end of the twentieth century. First, the individual sheets comprising the study area were pieced together and the accuracy of the map was evaluated. The accuracy found on the Newcombe map was 0.76 mm on the map scale, equivalent to 100.3 m. Route development during the twentieth century was then evaluated by comparing the routes digitized from the Newcombe map to digitized routes on a late twentieth-century map. The results do not reveal tremendous changes in path, shape, or number of routes. Instead, they merely indicate the natural development in their quality. This Historical GIS-based approach provided a useful technique for analyzing and comparing the line segments extracted from historical and modern maps. The implemented approach may also serve other geographical or historical studies aiming to examine the development of branched networks throughout history. 相似文献
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《International Journal of Digital Earth》2013,6(5):387-401
Abstract Geomorphologic and hydrologic research heavily depends on digital elevation models (DEM) which are currently being prepared from digital contours. The present study examines the use and applicability of freely available global elevation data source (3 arc seconds finished Shuttle Radar Topography Mission (SRTM)) in landform characterisation, geomorphometry, river basin studies and other allied scientific applications in comparison with contour elevation data derived from the surveyed topographical sheets. The relief data extracted from a conventionally digitised geo-information science dataset of topographic contours (1:50,000) are compared with the SRTM-DEM and the variations are analysed. The automated geomorphometric and landform parameters derived from the contour DEM and the computed statistical properties of those parameters have substantial agreement with the same parameters derived from the SRTM-DEM. At the same time, localised variations also exist in some spatial domains. Derivative landscape analysis outputs from the SRTM-DEM suggest the wide acceptability and applicability of the freely available SRTM data source, especially in the regional scale applications related to hydrological modelling, terrain characterisation, disaster management and land degradation studies. 相似文献
13.
提高大比例尺地形图航测成图精度的测量方法 总被引：1，自引：0，他引：1
结合在白银市城区1∶500比例尺地形图航空摄影数字化成图,以及酒钢厂区1∶500比例尺现状图测绘的实际作业生产,介绍布设地面标志点进行航空摄影测量的作业方法,比较布设地面标志点进行航空摄影测量与常规航空摄影测量的成图精度。 相似文献
14.
Completeness and classification correctness of features on topographic maps: An analysis of the estonian basic map 
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下载免费PDF全文 In an increasingly GIS‐literate world, the availability of quality topographic maps and map databases is critical for the numerous users of spatial data. Particularly governmental agencies, first responders, and utility and transportation services, rely on the completeness and classification correctness of these maps. Estonia has systematically updated its topographic Basic Map in digital form over the past 15 years. An analysis of the Estonian production process in the period 2003‐2006 provides a useful case study of both error types and error frequencies encountered in topographic mapping. Errors of completeness and classification correctness of topographic features are analyzed at two levels of specificity: in general, across all map sheets, and in detail according to the field‐workers who performed the mapping. The structure of errors at the two levels was different by geometry and error types; however, both systematic and individual errors were evident. The systematic errors indicated a need for revision and improvement of the data capture specifications, which was accomplished. The individual errors were addressed by additional training for the field‐workers involved. 相似文献
15.
针对DEM转换等高线时,现有方法不能方便、有效处理好曲线光滑与地貌精度损失之间的关系,提出了基于坡度分区滤波的DEM转换等高线方法。对不同的坡度分区采用不同大小的窗口进行均值滤波,并对滤波高程差值进行控制,较好地处理了曲线光滑与地貌精度损失之间的关系;同时,对计曲线之间的窄部首曲线进行自动识别和打断删除。基于该方法,利用ArcGIS+Python脚本开发了DEM到等高线自动转换工具,在数字广西地理空间框架建设1：1万DLG项目的等高线采集工作中得到了初步应用,取得了良好的效果。 相似文献
16.
目前,对于城市1∶500数字化地形图数据的获取与更新中,全野外数字测图仍是主要的测绘方式。如何利用新的测量手段提高生产效率和降低劳动强度,是值得关注的问题。文中阐述无人机和地面三维激光扫描仪新技术在城市基本地形图测绘中的应用,利用无人机航测生产的1∶500正射影像图成果,辅助进行全野外测图;利用地面三维激光扫描仪,将快速获取的三维点云数据加以处理,用于测绘成果质量检查。通过这些新技术,对提高1∶500城市基本地形图的生产效率进行有益的尝试,对同类工程具有借鉴意义。 相似文献
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矿区地形图动态自动修正系统初探 总被引：1，自引：0，他引：1
由于矿区特殊性,其地形图变化十分频繁,及时对变化区域或新测绘区域地形图进行修绘是一项十分重要的工作.通过对地形图计算机绘图理论的分析,开发一个矿区地形图动态自动修正系统.该系统特色之处首先是建立一个提取DXF格式地形图控制数据提取接口,并能根据提取数据和修正区域控制数据进行修正区域搜寻、开窗显示、TIN的生成、等高线追踪平滑,以及与原有地形图接边等功能;其次系统力求做到该功能模块的独立性,以能够成为数字化绘图平台或GIS系统绘图功能的补充,或为其该项功能的完善提供具体思路.最后,通过具体实例验证该系统功能的可行性和实用性. 相似文献
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论述了数字地形图中产生高程点与等高线错误的可能原因,分析了高程点和等高线在地形图中的空间位置关系及作为判断条件的数学关系,论述了解决问题的办法和判断规则,展示了通过编制计算机程序实现找出其错误的核心代码,此研究对于减轻质检人员在检查数字地形图的高程点与等高线错误时的劳动强度和提高工作效率很有意义。 相似文献
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胡晓娟 《测绘与空间地理信息》2011,34(5):218-220
结合大比例尺数字地形图的特点和管理需求,采用VB技术对AutoCAD软件进行二次开发,建立集调图、图形编辑、图形裁剪、图廓生成、地形图分幅于一体的大比例尺数字地形图管理系统,为大比例尺地形图的管理与使用提供了一个实用性的平台。 相似文献