GIS专业基于面向对象程序设计的DEM生成教学实验设计

数字高程模型是地理信息科学专业的必修课,DEM生成方法是该课程的核心知识点之一。通常以GIS软件为实验操作平台构建DEM,GIS软件提供良好的操作界面且简化教学过程,但软件同时会弱化学生对DEM生成过程的理解,而面向对象程序设计课程往往开设在数字高程模型课程之前。文中融合面向对象程序设计和数字高程模型课程知识点,采用面向对象程序设计思想对DEM课程中的DEM生成实验进行设计并实现,为GIS专业的DEM生成实验提供新的教学思路,提升DEM课程教学实践的品质和效果。     

顾及目标异质性的极化SAR图像非局部均值滤波

相干斑抑制是极化合成孔径雷达(Pol SAR)图像分析的重要预处理步骤。为了更好地抑制极化SAR图像中的相干斑,本文综合目标的异质性和结构信息,提出基于目标异质性的非局部均值滤波方法。首先利用K分布距离度量目标的异质性,并以异质性为基础,保留图像中的点、线等高异质性目标;然后计算图像块之间的异质性差异,最后将其作为度量非局部均值加权滤波像元相似性的权重系数,实现对Pol SAR图像的相干斑抑制。实验对比结果表明:本文方法能够有效地抑制相干斑,同时对细节信息和极化信息也具有良好的保持性,能够为后续的图像应用提供支持。     

太阳轨迹空间连续性的日照分析算法优化

针对日照分析模拟必须考虑众多真三维地形/地物的遮挡因素,传统的日照分析方法难以在现实世界的复杂地理场景中得出高效、准确分析结果的问题展开研究,基于太阳运行轨迹的空间连续性,利用数据缓存方法对遮挡图元进行预判,实现了日照分析算法的优化。应用实例表明,将该方法与空间划分方法配合使用,可以在保证运算结果正确的基础上,进一步提高日照分析的计算效率,从而实现复杂地理场景中准确、快速的日照分析计算。     

Integrity monitoring-based ambiguity validation for triple-carrier ambiguity resolution

GPS Solutions - Frequency diversity is expected to benefit the ambiguity resolution (AR) with the modernization of global navigation satellite system. As one classic AR method, triple-carrier AR...     

皖江城市带植被NPP时空变化及其气候响应

针对现有植被净初级生产力研究对城市圈、城市带尺度缺乏关注的问题,基于MODIS遥感数据、地面气象资料等,利用改进的CASA模型,结合回归分析、相关分析等方法探究了2000—2013年皖江城市带植被NPP的时空变化及其对气候因子的响应,为区域生态环境质量评价提供参考。结果表明:近14年来,皖江城市带植被NPP总体呈增加趋势;不同土地利用类型NPP差异显著,林地草地耕地建设用地未利用土地水体;年NPP均值呈现由南部向西北部减少的空间分布特征;植被NPP年际变化率较小,介于±10gC·m-2·a-1范围内;温度是影响研究区植被NPP时空变化的主要气候因子。     

Performance of RegCM4 over Major River Basins in China

A long-term simulation for the period 1990–2010 is conducted with the latest version of the International Centre for Theoretical Physics' Regional Climate Model(RegCM4), driven by ERA-Interim boundary conditions at a grid spacing of 25 km. The Community Land Model(CLM) is used to describe land surface processes, with updates in the surface parameters,including the land cover and surface emissivity. The simulation is compared against observations to evaluate the model performance in reproducing the present day climatology and interannual variability over the 10 main river basins in China,with focus on surface air temperature and precipitation. Temperature and precipitation from the ERA-Interim reanalysis are also considered in the model assessment. Results show that the model reproduces the present day climatology over China and its main river basins, with better performances in June–July–August compared to December–January–February(DJF).In DJF, we find a warm bias at high latitudes, underestimated precipitation in the south, and overestimated precipitation in the north. The model in general captures the observed interannual variability, with greater skill for temperature. We also find an underestimation of heavy precipitation events in eastern China, and an underestimation of consecutive dry days in northern China and the Tibetan Plateau. Similar biases for both mean climatology and extremes are found in the ERA-Interim reanalysis, indicating the difficulties for climate models in simulating extreme monsoon climate events over East Asia.     

Applicability of Kinetic Models for In Situ Combustion Processes with Different Oil Types

The in situ combustion (ISC) process is of interest as an enhanced oil recovery method because it is an alternative to traditional steam-based processes for heavy oil and bitumen recovery. ISC is a technique applicable outside the window of reservoir conditions deemed appropriate for steam injection (such as deeper and thinner reservoirs). The process involves complex chemical reactions and physical recovery mechanisms, and predicting the likelihood of successful ISC in field applications remains challenging. This paper describes a numerical investigation of the capability of different ISC kinetic models to predict the combustion behaviors of different types of oils (light oil, heavy oil, and bitumen). Three kinetic models (of Coats, Crookston, and Belgrave) were selected from literature and compared using data from four published combustion-tube experiments. The comparison procedure is as follows: (1) validate the numerical modeling of each kinetic model by matching the selected experimental results or duplicating the numerical results found in published literature; (2) adjust fluid viscosities and densities to match the fluid properties of each experiment;and (3) use each validated kinetic model to predict the performance of the other experiments without further tuning the kinetic parameters. The knowledge derived from the experiments provides guidance for choosing the appropriate kinetic model when no other data are available and for the preliminary design and screening study of a potential ISC project.     

皖南国际文化旅游示范区文化资源丰度评价

以皖南国际文化旅游示范区为研究对象,从文化与旅游融合发展的视角,通过构建区域文化资源丰度评价指标体系,对示范区各地市文化资源丰度进行测度,得出如下结论：皖南国际文化旅游示范区中黄山、安庆、宣城、池州4市的文化资源赋存丰度为优级;马鞍山、芜湖市为良好;铜陵市为差级,优级区主要集中在南部和东西部,南北差异明显。从文化资源组合状况来看,黄山市文化资源组合状况最好,品牌资源众多,开发潜力巨大;其次是宣城、安庆和池州3市,资源类型齐全,组合状态较好;马鞍山、铜陵和芜湖3市较差,类型相对单一,开发难度较大。建议政府部门及旅游业界据此结果,科学评估文化资源的价值和开发方向,探索旅游开发的有效模式,推动文化与旅游融合发展,实现示范区优秀文化传承与创新。     

中国陆区S波分型与上地幔地震各向异性

本文利用中国大陆区共8个台站所观测到地震事件的S波数据，采用相关分析的手段以 观测数据重建的技术，进行了S波分裂参数－快慢波延迟时间与快波偏振方向的计算，并分析了S波分裂参数与中国陆区上地幔物质运动的相互关系，研究了结果表明，兰州台下的S波分裂时差最小，北京台下的最大，中国东部地区上地幔运动方向以西北向为主，西部地区以北偏西为优势。     

地理信息系统开发方法的演进

随着计算机科学和软件工程技术的进步 ,GIS软件工程方法在不断地演进 ,越来越适合于GIS的开发。文中介绍和回顾了GIS在自身的发展过程中使用的一些软件工程方法 ,并初步探讨了为GIS项目选用软件开发方法的问题。