MAPGIS与AUTOCAD间数据转换在数字化制图中的应用

文章主要论述了MAPGIS和AUTOCAD之间数据如何转换,以及数据转换在数字化地质制图应用中的方法、操作步骤和应注意的问题.     

LRI与KBR数据检核GRACE-FO卫星精密轨道

GRACE-FO卫星定轨精度直接影响其反演地球重力场,评估检核轨道数据精度是保证重力场反演效果的重要步骤.自该卫星升空以来,已在轨观测近2年6个月,尚未见对各时期卫星轨道的检核分析.针对以上情况,提出了利用LRI与KBR数据检核GRACE-FO卫星精密轨道的方法,引入了基于信噪比确定权重系数的星间距离组合观测量作为参考...     

黄土基覆层边坡动力破坏特征的大型振动台试验研究

为了探讨黄土基覆层边坡动力破坏特征与加速度的响应关系,采用1︰20振动台试验,设置输入地震波幅值逐级增大,实时监测边坡裂缝试验全周期内发育规律,应用MATLAB动力破坏特征检测系统获取地表裂缝的基本信息,提出边坡表面动力破坏特征,并结合各工况监测点加速度峰值变化规律进行分析。得到如下结论：(1)输入加速度峰值0.6g时,坡顶和坡脚的裂缝宽度、裂缝面积均有跳跃性增长,表明土岩接触面部位土体已发生累进剪切破坏,滑面和坡面上的加速度峰值响应突变,振幅突变较大,表明边坡已经发生破坏。(2)沿坡面和滑面加速度放大系数均呈非线性增加,而沿坡面的放大系数在各工况下明显比沿滑面的大,说明加速度沿高程放大效应明显。(3)拉裂缝和剪切裂缝面积突增是边坡破坏的重要特征,贯通裂缝产生和加速度响应突变可以作为边坡动力破坏的依据。     

扎实做好第二次土地调查各项工作

国务院决定,今年7月1日将启动第二次全国土地调查,计划用3年时间,全面查清全国范围的土地利用状况,掌握真实的土地基础数据。[第一段]     

探讨雷电监测定位数据在人工影响天气中的应用

由于地理位置的原因,一些台站收不到雷达资料,在进行人工影响天气作业时对天气系统的判断存在一定盲目性,与天气雷达比较,雷电定位系统具有覆盖范围大、维持费用低及可连续长时间运行的优点。如果能有效地利用雷电监测数据对人工影响天气作业进行指导,将提高人工影响天气的作业效果。     

浅析无人机倾斜摄影测量数据的精准获取以及在地质灾害防治中的应用

利用无人机倾斜摄影非接触测量的优势对地质灾害防治区域进行航拍,快速高效地获取实景三维数据,制作大比例尺数字模型,定量提取精细的地表粗糙度、坡度、坡向等地形地貌参数。同时针对区域内典型的地质灾害体利用激光扫描仪（集成高精度GNSS和IMU惯导系统）开展精细扫描,快速获取微地貌等细节特征信息。在形成的“4D”产品基础上进行分析和反演,结合GIS等多学科技术建立地质灾害监测、分析、预警平台,提升相关部门对突发性地质灾害的分析、预警、处置和服务的能力,为地方政府对地质环境与地质灾害决策管理和社会服务提供技术支撑。     

Estimates of global M_2 internal tide energy fluxes using TOPEX/POSEIDON altimeter data

TOPEX/POSEIDON altimeter data from October 1992 to June 2002 are used to calculate the global barotropic M2 tidal currents using long-term tidal harmonic analysis. The tides calculated agree well with ADCP data obtained from the South China Sea (SCS). The maximum tide velocities along the semi-major axis and semi-minor axis can be computed from the tidal ellipse. The global distribution of M2 internal tide vertical energy flux from the sea bottom is calculated based on a linear internal wave generation model. The global vertical energy flux of M2 internal tide is 0.96 TW, with 0.36 TW in the Pacific, 0.31 TW in the Atlantic and 0.29 TW in the Indian Ocean, obtained in this study. The total horizontal energy flux of M2 internal tide radiating into the open ocean from the lateral boundaries is 0.13 TW, with 0.06 TW in the Pacific, 0.04TW in the Atlantic, and 0.03 TW in the Indian Ocean. The result shows that the principal lunar semi-diurnal tide M2 provides enough energy to maintain the large-scale thermohaline circulation of the ocean.     

Improvement of Urban Impervious Surface Estimation in Shanghai Using Landsat7 ETM＋ Data

This paper explores the potential to improve the impervious surface estimation accuracy using a multi-stage approach on the basis of vegetation-impervious surface-soil (V-I-S) model. In the first stage of Spectral Mixture Analysis (SMA) process, pixel purity index, a quantitative index for defining endmember quality, and a 3-dimensional endmember selection method were applied to refining endmembers. In the second stage, instead of obtaining impervious surface fraction by adding high and low albedo fractions directly, a linear regression model was built between impervious surface and high/low albedo using a random sampling method. The urban impervious surface distribution in the urban central area of Shanghai was predicted by the linear regression model. Estimation accuracy of spectral mixture analysis and impervious surface fraction were assessed using root mean square (RMS) and color aerial photography respectively. In comparison with three different research methods, this improved estimation method has a higher overall accuracy than traditional Linear Spectral Mixture Analysis (LSMA) method and the normalized SMA model both in root mean square error (RMSE) and standard error (SE). However, the model has a tendency to overestimate the impervious surface distribution. Foundation item: Under the auspices of National Natural Science Foundation of China (No. 40701177)     

三峡库区首获航空遥感数据

日前,中国国土资源航空物探遥感中心成功获取了三峡库区首批高精度航空遥感数据,标志着长江中上游（江津-宜昌段）1：5万航空遥感地质调查项目库区航空遥感调查工作全面展开。三峡地区属中低纬度亚热带气候区,常年以阴雨天居多,日照少,雾气重。为在最短时间内获取库区4万km^2高分辨率航空遥感影像,航遥中心积极与空军协调,