基于GeoSOT网格的“天绘一号”卫星影像数据组织

目前“天绘一号”卫星数据按自身行业特点, 建立具有自身特点的空间数据组织方式与记录方式的信息组织系统, 存在不便于跨部门间数据的检索、共享和整合困难, 本文提出了基于地球剖分框架GeoSOT的天绘影像数据组织模型, 并在尽量不改变现有的天绘数据组织的前提下, 通过在天绘数据库编目中增加剖分索引的方式, 实现天绘影像数据全球“虚拟一张网”的数据组织。通过试验证明, 在现有天绘影像数据组织的基础上, 进行剖分组织改造代价不大且数据整合效率显著。     

Nature and theoretical foundation of ecoregionalization:a case study in China

lintroductionPhysicalgeographers,ecologistSandotherresearchershavebeeninvolvedinanal}aingspahalchrenhationofvariousfactorsontheearthsurface,suchasbiome,close,andsoil,toexplainandunderstandthephysicogeographicalprocessesandtheirSPatialpatternssincetheestablislunentoftheacademicfieldsofgeogT'aphyandecology.Theynotedablythattheregional~onoffactorsonthe~~cewashelpfulnotonlytoimpellingthedevelopmentofgeographyandecology,butalsotobroadeningtheirapplicahons,andtheybeganclasssingfactorswithvallousmet…     

Mapping multiple tree species classes using a hierarchical procedure with optimized node variables and thresholds based on high spatial resolution satellite data

ABSTRACT

Tree species distribution mapping using remotely sensed data has long been an important research area. However, previous studies have rarely established a comprehensive and efficient classification procedure to obtain an accurate result. This study proposes a hierarchical classification procedure with optimized node variables and thresholds to classify tree species based on high spatial resolution satellite imagery. A classification tree structure consisting of parent and leaf nodes was designed based on user experience and visual interpretation. Spectral, textural, and topographic variables were extracted based on pre-segmented images. The random forest algorithm was used to select variables by ranking the impact of all variables. An iterating approach was used to optimize variables and thresholds in each loop by comprehensively considering the test accuracy and selected variables. The threshold range for each selected variable was determined by a statistical method considering the mean and standard deviation for two subnode types at each parent node. Classification of tree species was implemented using the optimized variables and thresholds. The results show that (1) the proposed procedure can accurately map the tree species distribution, with an overall accuracy of over 86% for both training and test stages; (2) critical variables for each class can be identified using this proposed procedure, and optimal variables of most tree plantation nodes are spectra related; (3) the overall forest classification accuracy using the proposed method is more accurate than that using the random forest (RF) and classification and regression tree (CART). The proposed approach provides results with 3.21% and 7.56% higher overall land cover classification accuracy and 4.68% and 10.28% higher overall forest classification accuracy than RF and CART, respectively.     

东喜马拉雅构造结南迦巴瓦岩群的解体

通过对研究区南迦巴瓦岩群的大比例尺填图工作，根据南迦巴瓦岩群的原岩建造、变质程度的不同、变形样式的差异，将其解体为在区域上具有可填性3套岩石组合——直白岩组、派乡岩组和多雄拉混合岩，三者之间均以构造面接触。     

我国前寒武纪地质研究进展与展望

前寒武纪地质学是现代地球科学中最活跃的学科之一。我国前寒武纪地质研究有着良好的条件和优良的传统，前寒武纪岩石在中国大陆上有广泛的分布，保存了从3800Ma到543Ma较完整的岩石、地层和生物形成与演化的历史记录，并蕴藏了丰富的矿产资源。简要回顾了近百年来我国前寒武纪研究的历史，取得的丰硕成果及巨大进展。概述了中国前寒武纪时期的大陆，特别是太古宙华北克拉通地壳演化的特殊性和复杂性，与世界其他地区的克拉通进行了对比。指出前寒武纪地质学在研究地球科学中仍然处于重要的位置，尤其是研究前寒武纪超大陆汇聚与裂解及前寒武纪成矿区带的划分已成为当今世界研究的热点。在此基础上，提出了对我国21世纪前寒武纪地质学的工作设想和展望。     

基于SPOT-5卫星影像的胶东地区果园信息分区分层提取方法研究

 研究了综合应用纹理、光谱及空间等信息建立SPOT-5图像分区分层自动提取果园信息模型的方法，取得了较好的分类精度。     

A progressive line simplification algorithm

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西北地区侏罗纪地质事件及其在地层划分对比中的意义

在大量实际资料的基础上,深入研究了西北地区陆相侏罗纪地层中记录的地质事件。从煤层特征、颜色特征、岩性特征、孢粉组合特征、植物群特征和双壳动物化石特征等方面,建立了西北地区陆相侏罗纪地层划分对比的标志。并认为这些生物事件和旋回沉积层的形成都与大范围内侏罗纪古气候变化密切相关,中侏罗世晚期到晚侏罗世末存在一次最为明显的升温事件。     

广西第四纪地层划分与对比

文章概略介绍了广西第四系划分与对比情况,确定了主要岩组的地质年代、孢粉组合特征及古气候古地理的变迁。