TERRA: Terrain Extraction from elevation Rasters through Repetitive Anisotropic filtering

Over the past decades, several filters have been developed to derive a Digital Terrain Model (DTM) from a Digital Surface Model (DSM), by means of filtering out aboveground objects such as vegetation. In this filtering process, however, one of the major challenges remains to precisely distinguish sharp terrain features, e.g. ridges, agricultural terraces or other anthropogenic geomorphology such as open-pit mines, riverbanks or road ramps. Hence, loss of elevation data around terrain edges (and consequent smoothing) is very common with existing algorithms. In terraced landscapes, the preservation of precise geomorphology is of key importance in digital terrain analyses, such as hydrologic and erosion modelling, or automatic feature recognition and inventorying. In this work, we propose a new filtering method called TERRA (Terrain Extraction from elevation Rasters through Repetitive Anisotropic filtering). The novelty of the algorithm lies within its usage of terrain aspect to guide the anisotropic filtering direction, therefore maximising the preservation of terrain edges. We derived six DTMs from DSMs using UAV Structure from Motion (SfM) photogrammetry, laser altimetry and satellite sources (grid resolutions ranging from 0.1–1.0 m). The results indicated a close agreement of DTMs filtered using the TERRA algorithm and reference DTMs, while terrace risers were well preserved even under thick canopies of vines and trees. Compared to existing filtering approaches, TERRA performed well in minimising Type I errors (false ground removal), while Type II errors occurred locally where vegetation was covering the terrace edges. Given the promising filtering performance, and supported by the minimal requirements of parameterisation and computation, the TERRA algorithm could be a useful tool in DTM preparation for digital terrain analysis of agricultural terraces and similar hillslopes characterised by a complex mosaic of sharp terrain and non-terrain features.     

基于实景三维的露天矿山开采动态监管方法研究

采用三维地质建模技术,利用地质勘查数据,构建三维矿体模型、采矿区范围模型,并实现地上下三维一体化,整合完成露天矿山地上下三维模型,作为露天矿山动态开采的信息基础,进行了越界超采监测、开采量监测、开采活动监测、开采历史监测,总结了一套有效的露天矿山开采监测技术方法.     

Terrain characterization using SRTM data

Earth’s surface possesses relief because the geomorphic processes operate at different rates, and geologic structure plays a dominant role in the evolution of landforms (Thornbury, 1954). The spatial pattern of relief yields the topographic mosaic of a terrain and is normally extracted from the topographical maps which are available at various scales. As cartographic abstractions are scale dependent, topographical maps are rarely good inputs for terrain analysis. Currently, the shuttle radar topography mission (SRTM) provides one of the most complete, highest resolution digital elevation model (DEM) of the Earth. It is an ideal data-set for precise terrain analysis and topographic characterization in terms of the nature of altimetric distribution, relief aspects, patterns of lineaments and surface slope, topographic profiles and their visualisation, correlation between geology and topography, hypsometric attributes and finally, the hierarchy of terrain sub-units. The present paper extracts the above geomorphic features and terrain character of part of the Chotonagpur plateau and the Dulung River basin therein using SRTM data.     

露天煤矿数字地质模型的建立及在虚拟开采中的应用研究

为了对露天煤矿剥、采、排和土地复垦的进行预控制,需要对露天矿生产进行预演,计算相关数据。采用层面模型建立露天矿的地质模型,以"多对角线交换循环算法"结合"凸包推进算法"建立约束TIN结构层面。根据露天矿开采推进的特点建立以台阶为单元的分层式开采模型,在地质模型和开采模型的基础上,根据露天矿实际生产情况建立开采模板,采用"人工交互式推进"实现露天矿的虚拟开采。     

Monitoring active open-pit mine stability in the Rhenish coalfields of Germany using a coherence-based SBAS method

With the recent progress in synthetic aperture radar (SAR) technology, especially the new generation of SAR satellites (Sentinel-1 and TerraSAR-X), our ability to assess slope stability in open-pit mines has significantly improved. The main objective of this work is to map ground displacement and slope instability over three open-pit mines, namely, Hambach, Garzweiler and Inden, in the Rhenish coalfields of Germany to provide long-term monitoring solutions for open-pit mining operations and their surroundings. Three SAR datasets, including Sentinel-1A data in ascending and descending orbits and TerraSAR-X data in a descending orbit, were processed by a modified small baseline subset (SBAS) algorithm, called coherence-based SBAS, to retrieve ground displacement related to the three open-pit mines and their surroundings. Despite the continuously changing topography over these active open-pit mines, the small perpendicular baselines of both Sentinel-1A and TerraSAR-X data were not affected by DEM errors and hence could yield accurate estimates of surface displacement. Significant land subsidence was observed over reclaimed areas, with rates exceeding 500 mm/yr, 380 mm/yr, and 310 mm/yr for the Hambach, Garzweiler and Inden mine, respectively. The compaction process of waste materials is the main contributor to land subsidence. Land uplift was found over the areas near the active working parts of the mines, which was probably due to excavation activities. Horizontal displacement retrieved from the combination of ascending and descending data was analysed, revealing an eastward movement with a maximum rate of ∼120 mm/yr on the western flank and a westward movement with a maximum rate of ∼ 60 mm/yr on the eastern flank of the pit. Former open-pit mines Fortuna-Garsdorf and Berghein in the eastern part of Rhenish coalfields, already reclaimed for agriculture, also show subsidence, at locations reaching 150 mm/yr. The interferometric results were compared, whenever possible, with groundwater information to analyse the possible reasons for ground deformation over the mines and their surroundings.     

露天矿卡车调度系统关键技术研究

随着露天矿产量规模的不断扩大及设备大型化、机械化、自动化程度的不断提高,采运成本占矿山生产成本的比例也越来越高,优化车队运行、准确执行生产计划,以提高矿山产量,节约费用,取得较高经济效益显得尤为重要。露天矿卡车调度系统是集GPS定位技术、GPRS通信技术、GIS管理技术、运筹学以及优化理论于一身的综合系统。本文主要研究了该系统的构成以及设计该系统所需要的关键性技术问题,并提出了相应的解决方法。     

无人机在露天矿山监测中的应用

在露天矿山开采过程中，对矿山进行实时动态监测很有必要，它不仅能够实时掌握开采进度和开采方案实施的准确性，还有利于数字矿山建设。本文以河北省保定市涞源县某露天矿区为例，利用Pix4Dmapper软件对无人机航拍影像进行数据采集与处理，获取矿区的三维点云数据、数字正射影像和数字地表模型，并利用ArcGIS和Global Mapper软件对生产成果进行矿山开发占地分析，实现露天矿山三维可视化。本文为准确掌握矿山环境治理执行情况，把握矿山开发整体情况给予了有力的参考和借鉴作用。     

基于GIS的岩溶古地貌定量刻画方法分析研究

恢复岩溶古地貌对于分析岩溶储层发育特征具有重要作用。目前关于岩溶古地貌的恢复多为定性方法,定量刻画古地貌的水平有待提高,而GIS在定量分析处理地貌方面独具优势。以高石梯—磨溪区块灯四段岩溶储层为例,在经典古地貌恢复方法的基础上,从GIS的地貌因子出发,提取了包括高程、坡度、地表切割深度、地表粗糙度、地形起伏度在内的地形因子以及包括水流长度、河流等级、流域分析在内的水文因子;再选取核心地形因子,并对地貌因子进行敏感性评价,结果显示高程、坡度和地形起伏度对地形的表征贡献较大。以地貌成因—形态分类原则为地貌分类方案,对敏感地形因子进行重分类操作后作叠加分析处理,地貌分区成图显示研究区由岩溶高地、岩溶缓坡、岩溶缓坡过渡带和岩溶洼地4类地貌单元组成。对岩溶古地貌进行分析评价发现,岩溶缓坡为油气良好集聚地,地貌划分结果与储层分布具有相关性。     

The relation between degree-2160 spectral models of Earth’s gravitational and topographic potential: a guide on global correlation measures and their dependency on approximation effects

Comparisons between high-degree models of the Earth’s topographic and gravitational potential may give insight into the quality and resolution of the source data sets, provide feedback on the modelling techniques and help to better understand the gravity field composition. Degree correlations (cross-correlation coefficients) or reduction rates (quantifying the amount of topographic signal contained in the gravitational potential) are indicators used in a number of contemporary studies. However, depending on the modelling techniques and underlying levels of approximation, the correlation at high degrees may vary significantly, as do the conclusions drawn. The present paper addresses this problem by attempting to provide a guide on global correlation measures with particular emphasis on approximation effects and variants of topographic potential modelling. We investigate and discuss the impact of different effects (e.g., truncation of series expansions of the topographic potential, mass compression, ellipsoidal versus spherical approximation, ellipsoidal harmonic coefficient versus spherical harmonic coefficient (SHC) representation) on correlation measures. Our study demonstrates that the correlation coefficients are realistic only when the model’s harmonic coefficients of a given degree are largely independent of the coefficients of other degrees, permitting degree-wise evaluations. This is the case, e.g., when both models are represented in terms of SHCs and spherical approximation (i.e. spherical arrangement of field-generating masses). Alternatively, a representation in ellipsoidal harmonics can be combined with ellipsoidal approximation. The usual ellipsoidal approximation level (i.e. ellipsoidal mass arrangement) is shown to bias correlation coefficients when SHCs are used. Importantly, gravity models from the International Centre for Global Earth Models (ICGEM) are inherently based on this approximation level. A transformation is presented that enables a transformation of ICGEM geopotential models from ellipsoidal to spherical approximation. The transformation is applied to generate a spherical transform of EGM2008 (sphEGM2008) that can meaningfully be correlated degree-wise with the topographic potential. We exploit this new technique and compare a number of models of topographic potential constituents (e.g., potential implied by land topography, ocean water masses) based on the Earth2014 global relief model and a mass-layer forward modelling technique with sphEGM2008. Different to previous findings, our results show very significant short-scale correlation between Earth’s gravitational potential and the potential generated by Earth’s land topography (correlation +0.92, and 60% of EGM2008 signals are delivered through the forward modelling). Our tests reveal that the potential generated by Earth’s oceans water masses is largely unrelated to the geopotential at short scales, suggesting that altimetry-derived gravity and/or bathymetric data sets are significantly underpowered at 5 arc-min scales. We further decompose the topographic potential into the Bouguer shell and terrain correction and show that they are responsible for about 20 and 25% of EGM2008 short-scale signals, respectively. As a general conclusion, the paper shows the importance of using compatible models in topographic/gravitational potential comparisons and recommends the use of SHCs together with spherical approximation or EHCs with ellipsoidal approximation in order to avoid biases in the correlation measures.     

基于RS和GIS的神府煤矿区开采秩序监测

以对煤炭资源开采秩序监测为研究主题,以RS和GIS为技术支撑,结合遥感影像数据与所搜集到的矿权信息、基础地形图等资料,采用人机交互式解译的方法,对陕西神府煤矿区煤炭资源开采秩序进行了动态监测,以达到为执法部门低成本快速高效地打击非法采矿行为提供科学执法依据的目的。     

A new landscape metric for the identification of terraced sites: The Slope Local Length of Auto-Correlation (SLLAC)

This work presents the potential for high-resolution remote sensing data (LiDAR digital terrain models) to determine the spatial heterogeneity of terraced landscapes. The study objective is achieved through the identification of a new parameter that distinguishes this unique landscape form from more natural land formations. The morphological indicator proposed is called the Slope Local Length of Auto-Correlation (SLLAC), and it is derived from the local analysis of slope self-similarity. The SLACC is obtained over two steps: (i) calculating the correlation between a slope patch and a defined surrounding area and (ii) identifying the characteristic length of correlation for each neighbourhood. The SLLAC map texture can be measured using a surface metrology metric called the second derivative of peaks, or Spc. For the present study, we tested the algorithm for two types of landscapes: a Mediterranean and an Alpine one. The research method involved an examination of both real LiDAR DTMs and simulated ones, in which it was possible to control terrace shapes and the percentage of area covered by terraces. The results indicate that SLLAC maps exhibit a random aspect for natural surfaces. In contrast, terraced landscapes demonstrate a higher degree of order, and this behaviour is independent of the morphological context and terracing system. The outcomes of this work also prove that Spc values decrease as the area of terraced surfaces increases within the investigated region: the Spc for terraced areas is significantly different from the Spc of a natural landscape. In areas of smooth natural morphology, the Spc identifies terraced areas with a 20% minimum height range covered in terraces. In contrast, in areas of steep morphologies and vertical cliffs, the algorithm performs well when terraces cover at least 50% of the investigated surface. Given the increasing importance of terraced landscapes, the proposed procedure offers a significant and promising tool for the exploration of spatial heterogeneity in terraced sites.     

低空无人机航测露天矿三维重构方法与试验

随着无人机应用的普及和数码相机性能的提升,利用无人机搭载数码相机快速获取矿区航测影像,配合适量控制点得到符合精度的三维数据成为可能。本文介绍了一种采用测图鹰X100搭载SONY a7R数码相机进行外业数据采集,借助C++和OpenCV配合少量地面控制点进行光束法平差,并用PMVS算法生成密集点云的低成本快速高效露天矿三维重构方法。通过在露天矿试验,结果表明该方法所得DOM和DSM的平面中误差为0.113 m,高程中误差为0.121 m,邻近地物点间距中误差为0.151 m,均满足1：500地形图国家标准的精度要求。     

利用短基线集InSAR技术监测抚顺市地面沉降

抚顺市是一座因煤而兴起的综合型重工业城市,矿产的大量开采导致了大范围的地面沉降。针对这一问题,为了有效监测抚顺市的地表形变,本文利用短基线集（SBAS）技术对覆盖抚顺市部分地区的12景COSMO-SkyMed高分辨率SAR数据进行了处理,获得了该研究区域的地面沉降分布和沉降速率图。试验结果表明,研究区整体呈现出沉降的趋势,沉降速率大部分在-25~-45 mm/a的范围内。其中新抚区沉降最为严重,有2个沉降严重的区域,最大沉降速率达到了-186 mm/a。该试验结果为抚顺市露天矿采矿导致的地面沉降与地质灾害监测提供了切实有利的数据参考。     

“高分一号02、03、04星”卫星数据在矿山开发环境遥感监测中的初步应用评价

"高分一号02、03、04"卫星是国家第一个民用高分辨星座,3星成功组网后,将大幅度提高山水林田湖草、矿产等自然资源全要素、全覆盖、全天候的实时调查监测能力。为了更好地了解卫星的应用性能,充分发挥和利用好高分一号02、03、04卫星数据在矿山开发环境调查工作中的应用。文章利用高分一号02、03、04卫星在河北迁西、遵化,山东招远、龙口地区的相关影像数据开展了矿山开发环境遥感调查应用评价,从地下、露天矿山的开发及环境信息的识别,以及不同数据源对比分析等方面分别进行评价。结果表明,高分一号02、03、04卫星数据能有效识别露天矿山开发和环境等要素信息,可解译出部分地下开采矿山的矿山地物等要素,满足1∶25 000的矿山遥感调查工作,可为矿山环境遥感监测提供又一强有力的数据支撑。     

典型煤炭矿区生态健康遥感诊断

煤炭资源是我国重要的一次性能源,科学监测与评估矿区生态健康,对于维持经济发展与生态健康的平衡至关重要。本文选取位于山西省的3处典型煤炭矿区,基于2001—2021年的Landsat遥感数据,利用目视解译方法对露天矿区进行了多年用地类型演变格局分析;并分别对3处典型矿区的绿度、湿度、干度、热度进行了估算,应用知识粒度熵的权重计算方法,综合构建了矿区遥感生态指数(RSEI),完成了矿区生态健康多年遥感诊断。结果表明,两处露天矿区呈现边开采边复垦的生产模式,各有半数的研究年份RESI区域均值达到0.5以上;地下矿区的开采工作基本不造成地上扰动,其2001年以来的生态健康状况较为稳定,RSEI均值在0.7上下浮动;3处矿区2021年的RSEI均值分别为0.53、0.48、0.70。本文改进了传统的遥感生态指数构建方法,为煤炭矿区的长时序生态监测与遥感诊断提供了科学支撑。     

板桥稀土矿遥感找矿信息提取与矿产预测研究

通过对离子吸附型稀土矿成矿规律的分析,从浙江省板桥地区的遥感地质特征研究入手,在研究区地表范围内进行稀土遥感找矿信息的提取。首先利用SPOT图像和DEM数据构建的坡度数据对与稀土成矿相关的地貌单元进行解译;然后通过光谱特征分析和基于ASTER图像的矿物遥感异常提取,获取与成矿相关的高岭土、绢云母、绿泥石等风化特征矿物的分布信息;最后叠合分析地貌、坡度及异常提取结果,进行稀土遥感找矿预测。与地质调查资料及化探数据的对比分析证实,上述方法对圈定1∶5万的大比例尺离子吸附型稀土矿分布范围是有效的,可为更详细的稀土矿产资源潜力评价提供依据。     

INSAR技术在海州露天矿边坡变形监测中的应用研究

露天矿边坡的变形监测一直是矿山安全生产的重要工作,运用合成孔径雷达干涉(INSAR)测量技术对边坡进行监测是近年来微波遥感研究的一个重要方向。本文分析了INSAR技术在边坡变形监测中的技术优势及研究的进展情况,并利用海州露天矿传统监测实测数据和INSAR监测进行比较,结果表明,INSAR技术可以实现对大型露天矿边坡有效地监测,具有一定的技术优势和广阔的应用前景。     

Geospatial Technologies for National Geomorphology and Lineament Mapping Project – A Case Study of Goa State

A three level classification system, based on the genesis of landforms, was used to map the geomorphology of the Goa state. The first level corresponds to the process that was responsible for landform generation, the second level or the intermediate level was assigned based on the morphography, and the third level corresponds to the individual landforms units identified based on the morphostructure. The mapping was carried out using IRS-P6 LISS-III (23.5 m) satellite image as the primary data source. Ancillary data such as geological map, topographic map, digital elevation model (DEM), field data collected by global positioning system (GPS) and web portals for image visualisation, were also used for the mapping purpose. A new software designed for mapping landforms based on the genesis, was used in this study to create a seamless geomorphology and lineament database of the Goa state in a GIS environment. A total of 58 landforms within six types of genetic classes were mapped in this area. Similarly, structural and geomorphic lineaments were also delineated using the satellite data. The database created has multi-purpose usability such as environmental studies, mining activity assessment, coastal zone management and wasteland development, since the classification system used is focused on processes, not theme specific.     

无人机航空摄影测量技术在矿区地形测量中的应用研究

无人机摄影测量是中小面积地形测绘的重要手段,具有低成本、高效率、高精度、信息量大、产品可以重复使用的优点,弥补了传统方法的不足。本文简要介绍了无人机航空摄影测量技术,从工程实例中,进一步论述了利用无人机,搭载非量测型相机,在地形复杂的高山矿区进行地形测量的过程和方法,评估了点位精度误差,希望能为相关领域研究人员提供借鉴。     

Analysing topographical changes in open cast coal-mining region of Patratu,Jharkhand using CARTOSAT-I Stereopair satellite images

This study provides an assessment of changes in the terrain topography due to opencast coal mining in the Patratu region of Jharkhand state during the period of 1962–2007. It demonstrated the potential of digital elevation model (DEM) differencing technique using Cartosat-I satellite (2007) derived DEM with reference to DEM derived from contours obtained from Survey of India topographical map (1962). The topographical changes through DEM differencing revealed positive relief changes (up to 49 m) due to coal-mining overburden dumps. The dumping of overburden near the banks of perennial Damodar River also caused positive topographic changes (up to 20 m) indicating adverse effects on its hydrological regime. Negative relief changes are represents by deep depressions (up to 66 m) created within coal mines due to the extraction of coal. These depression areas within the abundant mines generally become the zones of water accumulation causing wastage of surface and ground water resources.