提高城市大比例尺地形图转换到CGCS2000精度的探讨

针对在进行城市坐标系中的大比例尺地形图转换到CGCS2000中,采用统一区域坐标转换模型进行整体转换,将会使地形图在转换后的精度不能满足成图精度要求,提出了通过对区域内的所有控制点进行兼容性检测,剔除不能满足精度要求的点后,对所有控制点构建TIN,然后采用仿射变换模型分块对各三角形内的大比例尺地形图进行转换,从而实现提...     

粤西沿海震动图的生成和研究

震动图是描绘地震产生的地面运动和可能破坏情况的有效工具,主要包括峰值地面速度(PGV)等值线图、峰值地面加速度(PGA)等值线图和仪器烈度分布图等.基于华南数字地震台网记录到的2010年7月9日MS3.7级阳江地震的数据资料,利用SAC和GMT软件从记录到的地震波形数据提取地面运动参数,生成了PGV和PGA等值线图,并...     

Regional mapping and characterisation of old landslides in hilly regions using LiDAR-based imagery in Southern Flanders

Analysis of LiDAR-derived imagery led to the discovery of more than 330 pre-Holocene to recent landslides in Southern Flanders (4850 km²). The morphology of three landslides, including the 266.5 ha deep-seated gravitational slope deformation in Alden Biesen, was investigated in more detail. The analysis of the morphological and topographical characteristics (width–length relation, frequency–area distribution and topographical threshold) of the landslides revealed important differences compared to the characteristics reported in other landslide studies, and helped understanding possible landslide triggering mechanisms. Especially the possibility of a seismic origin of the landslides was investigated. Finally, a heuristic model for region-wide landslide susceptibility mapping was successfully tested. The susceptibility model and map allow prediction of future landslide locations and contribute to better understanding the role of individual causal factors on landslide location and spatial density. The results suggest that landslides on low-gradient, soil-mantled hills are a more important contributor to landscape evolution of hilly areas than was hitherto thought. The morphology of all hilly regions of Flanders is clearly marked by landslide processes and higher landslide densities often coincide with the presence of quaternary active faults. This study further shows that high-resolution topographical data such as LiDAR significantly contributes to a better detection of old, previously unknown landslides.     

1950—2020年东北地区林地时空变化特征分析

基于地形图、土地利用现状图提取并分析1950—2020年东北地区林地时空变化格局。结果表明：① 地形图中记载的林地信息能有效反映20世纪中期东北地区林地基本特征;研究期内林地呈先增后减态势,增幅达10.04×10⁴ km²,同期覆盖率从34.67%增至44.97%;市域林地均呈增加态势,净增幅前5的市域均超5 000 km²。② 研究期内林地不变、增加和减少区面积分别为28.36×10⁴ km²、15.49×10⁴ km²和5.45×10⁴ km²;林地不变区沿长白山、大小兴安岭呈倒U字形分布,占2020年林地面积的64.68%;林地增加区集中于辽河平原、长白山西侧、三江平原东侧、大兴安岭东西两侧;林地减少区零星分散、未呈明显集聚。③ 林地减少的流向表明,农业拓垦是东北地区林地减少的主因,侵占林地规模占林地减少量的88.18%,转化为耕地的区域主要分布在平原与山脉结合处及河谷地带;河流水体与城乡建设占用的林地基本相当,约占林地减少量的2.00%,城乡建设未对林地造成较大损坏。④ 研究期立地条件有大幅改善,林地距城镇平均距离缩减2.26 km,半数新增林地位于城镇10 km范围内;林地平均高程下降41.44 m,超半数新增林地位于高程300 m以内,林地向城镇延伸和“下山进平原”现象明显。     

大洋洲地区系列地质图件编制

通过资料收集、资料取舍、建立数据库、图件编制与校核,编制完成了大洋洲地区1：500万比例尺的地质图、大地构造图、矿产图、成矿区划和找矿预测图等主要图件,多幅单矿种矿产图等次要图件,物探、化探、遥感信息等辅助图件,以及局部地区（州）或重要矿种的参考图件,是一次对大洋洲地区地质矿产资料的大集成。通过编图和建库初步熟悉了大洋洲地区的地质矿产概况,为查询、访问和提取大洋洲地区的地质矿产资料提供了方便。     

Comparing maps to symplectic integrators in a galactic type Hamiltonian

We obtain thex - p _xPoincare phase plane for a two dimensional, resonant, galactic type Hamiltonian using conventional numerical integration, a second order symplectic integrator and a map based on the averaged Hamiltonian. It is found that all three methods give good results, for small values of the perturbation parameter, while the symplectic integrator does a better job than the mapping, for large perturbations. The dynamical spectra are used to distinguish between regular and chaotic motion.     

水文地质的研究进展与研究趋势 ——基于CiteSpace的可视化分析

水文地质学科作为基础学科在生态文明的发展中发挥着重要的推动作用,了解学科发展动态有助于发现和总结研究方法和研究热点,为未来的发展指明方向。本文通过中国知网（CNKI）数据库检索,所得数据运用CiteSpace进行可视化处理,得到水文地质学科研究成果的关键词共现图谱、关键词聚类图谱、关键词聚类时间线图谱和关键词突现图谱。通过对2000—2021年水文地质发展与趋势的研究图谱进行分析解读,认为水文地质发展经历了萌芽、初期、稳定和爆发４个时间阶段,并且未来发展趋势看好;研究内容分为基础性理论研究（找水水文地质学）、技术应用性研究（资源水文地质学）和多学科交叉性研究（生态环境水文地质学）;同时,在国家近年的政策、理念下,多学科交叉性研究已是水文地质科学研究在未来的大体趋势。     

A method of downscaling temperature maps based on analytical hillshading for use in species distribution modelling

Climate maps have been widely used for the construction of species distribution models. These maps derive from interpolation of data collected by meteorological stations. The sparse distribution of stations generates maps with coarse spatial resolution that are unable to detect microclimates or areas that can serve as plant or animal refuges. This work proposes a method for downscaling temperature maps using the solar radiation falling upon hillsides as predictor for the influence of relief on local variability. Solar irradiance is estimated from a digital elevation model of the study area using a routine based on analytical hillshading. Some examples of downscaling from 1 km to 25 m spatial resolution are shown. The results are compared with the surface temperature maps from Landsat 8 satellite imagery.     

Complexity reduction in choropleth map animations by autocorrelation weighted generalization of time-series data

Choropleth map animation is widely used to show the development of spatial processes over time. Although animation congruently depicts change, the rapid succession of complex map scenes easily exceeds the human cognitive capacity, causing map users to miss important information. Hence, a reduction of the visual complexity of map animations is desirable. This article builds on research related to complexity reduction of static choropleth maps. It proposes value generalization of choropleth time-series data in space and time, by using a method that adapts to the degree of global spatiotemporal autocorrelation within the dataset. A combination with upstream algorithms for local outlier detection results in less complex map animations focusing on large-scale patterns while still preserving significant local deviations in space and time. An according software application allows for in-depth exploration of the spatial and temporal autocorrelation structures in time-series data and provides control over the whole process of generalization.     

海岸带地质工作中陆海统筹的方法论探讨

陆海统筹是我国海岸带地质工作的重要方向,但以往的海岸带地质工作通常按陆区和海区分别开展,对如何实现陆海统筹没有形成统一认识。上海作为我国率先开展海岸带地质工作的地区之一,在陆海统筹方面进行了一些有益尝试,积累了一定经验。基于这些实践经验,并结合国内外海岸带地质工作现状,对海岸带地质工作中陆海统筹的方法论进行了探讨,提出了海岸带地质工作中陆海统筹应包含陆海成果一体化和以水体为媒介实现陆海联动的两个基本要求。研究认为: 在外业工作部署上,应发挥陆区河流和海区海岛的中介作用,着眼于区域性而非局部地区的地质成果编制; 在地质环境监测上,以海堤或岸线为纽带对陆区和海区进行同步监测; 在成果图件编制上,为实现陆海成果的有机整合,统一陆海数据标准是关键,在保存数据科学信息的前提下适当简化数据等级的分类。