A comparative analysis of gridding systems for point-based land cover/use analysis

For spatial analyses, raster land cover/use maps are converted into points, where each point holds attribute of its corresponding land cover/use. However, these are not identical in terms of areas or shapes; thus assigning a point to each isolated shape is not an adequate solution and for that gridding is suggested. Square, hexagon and triangle are among the basic land use gridding systems where each of them has its own advantages in such process. This research aims to compare the systems in providing accurate representations of the original land cover/use maps, assess the data loss while increasing resolution and suggest suitable gridding system. The research finds the errors in area and feature numbers as criteria for selected classes. Modules that find out errors in each scale considering each criterion and class alone are proposed. The modules suggest both the best system for each criterion alone and for combined criteria.     

影响正射影像生成质量的因素分析

制作DOM的方法越来越多,影响DOM生成质量的因素也很多,以数码相机获取的影像数据为例,分析了应用ERDAS2011LPS制作正射影像过程中影响DOM精度的若干因素。     

A preliminary version of a catalog of high-low-mass X-ray binaries

We introduce a catalogue of X-ray binaries. The full catalogue is available at http://astroa.physics.metu.edu.tr/XRBC/. The aim of this catalogue is to provide basic information about X-ray sources and their counterparts. The catalog contains positions, information about distances and counterparts, spectral, photometric and timing properties of the X-ray sources in the X-ray and optical bands, as well as references. The list of references, comments and the catalog as a whole will be periodically updated to include the most up-to-date information about all X-ray binaries and guide users to the recent literature on individual sources. In some cases, there is some doubt about the nature of an X-ray source, which has been noted. The sources are ordered according to right ascension. Here, we present a guide to the organization of the full catalogue. The full catalogue is represented here with an excerpt containing two HMXBs and two LMXBs as examples.     

利用SAR图像监测海上石油污染的实验分析

本文讨论了利用ＳＡＲ 图像监测海上石油污染的理论依据和环境条件,并根据ＲＡＤＡＲＳＡＴ 卫星装载的合成孔径雷达（ＳＡＲ）图像对渤海ＣＢ－６Ａ 井组发生的原油（气）泄漏事件进行了初步的研究和分析。     

西昆仑大红柳滩岩体地质和地球化学特征及对岩石成因的制约

新疆西昆仑康西瓦断裂带南缘的巴颜喀拉褶断带中分布着中生代三十里营房-泉水沟岩浆岩带,该带中最典型的岩体即为大红柳滩岩体,其主要岩性为中细粒二长花岗岩。结合锆石阴极发光图像(CL)和U、Th元素特征,通过SHRIMP锆石U-Pb定年,获得大红柳滩二长花岗岩体的年龄为220±2.2~217.4±2.2 Ma,时代属晚三叠世(T3)。二长花岗岩含石榴子石和电气石,具有高硅(SiO2为71.77%~74.20%)、富碱(Na2O+K2O为6.18%~8.02%)、富钾(K2O为3.03%~5.30%)、铝饱和指数较高(A/CNK介于1.20~1.59)的典型特点,属高钾钙碱性过铝质系列。岩石相对富集轻稀土且轻重稀土元素分馏明显(LREE/HREE为10.21~11.82,(La/Yb)N为24.06~31.65),具有强烈的铕负异常(δEu为0.25~0.44);明显富集Ta、Hf等高场强元素及Rb、Th、U等大离子亲石元素,而贫Ba、Sr、Ti、Nb、Zr等元素,显示经历了较高程度的分异演化(分异指数DI平均89.40%),综合矿物组合和地球化学特征的判别表明,大红柳滩岩体属于高分异的S型花岗岩,是同碰撞背景下壳源物质部分熔融的产物。根据岩体的成因类型并结合区域构造环境演化,分析认为晚三叠世随着古特提斯洋向北消减直至最终闭合,构造应力由俯冲作用转化为碰撞挤压作用环境时形成了大红柳滩岩体,表明该区在晚三叠世已进入陆-陆碰撞造山的构造演化阶段。     

无地面控制的海岸带航空遥感测量精度研究——机载LiDAR用于胶州湾海岸带测量

海岛海岸带地区,地理位置特殊,不便地形测量;对该区域进行航空遥感测量时,由于区域内大部分为低纹理地区,进行同名点匹配有困难,且不易进行野外控制点加密测量。机载(LIDAR)因其发射的激光脉冲能部分地穿透树林遮挡,具有一定的透水性能,能获得滩涂地区的高程,并且其系统配备的全球定位系统(GPS)和惯性测量系统(INS),使其定位精度得到很好的保证。文中选用胶州湾沿岸为试验区域,采用Leica公司的ALS70在低潮时进行测区的数据获取,并对结果进行精度分析,得出在该区域采用机载激光扫描系统ALS70进行无野外控制点加密的航空遥感,成果精度能满足1∶5 000比例尺测图的需要。     

Abundance quantification by independent component analysis of hyperspectral imagery for oil spill coverage calculation

The estimation of oil spill coverage is an important part of monitoring of oil spills at sea.The spatial resolution of images collected by airborne hyper-spectral remote sensing limits both the detection of oil spills and the accuracy of estimates of their size.We consider at-sea oil spills with zonal distribution in this paper and improve the traditional independent component analysis algorithm.For each independent component we added two constraint conditions:non-negativity and constant sum.We use priority weighting by higher-order statistics,and then the spectral angle match method to overcome the order nondeterminacy.By these steps,endmembers can be extracted and abundance quantified simultaneously.To examine the coverage of a real oil spill and correct our estimate,a simulation experiment and a real experiment were designed using the algorithm described above.The result indicated that,for the simulation data,the abundance estimation error is 2.52% and minimum root mean square error of the reconstructed image is 0.030 6.We estimated the oil spill rate and area based on eight hyper-spectral remote sensing images collected by an airborne survey of Shandong Changdao in 2011.The total oil spill area was 0.224 km~2,and the oil spill rate was 22.89%.The method we demonstrate in this paper can be used for the automatic monitoring of oil spill coverage rates.It also allows the accurate estimation of the oil spill area.     

Elemental abundance analyses with DAO spectrograms – XXIII. The superficially normal stars 28 And (A7 III) and 99 Her (F7 V)

Elemental abundances of 28 And (A7 III) and 99 Her (F7 V), which have modest rotational velocities, are derived in a manner consistent with previous studies in this series of papers. The values for 28 And, a δ Scuti variable, show that it is slightly metal-poor, but not a classical Am star. 99 Her, which is somewhat more metal-poor, has a rather small microturbulence for its spectral type.