实时交通数据支持下的医疗服务时空可达性分析

针对现有城市医疗服务可达性分析方法未考虑就医偏好,导致测算结果与居民实际感受相差较大的问题,本文提出了一种顾及时间和距离成本偏好的医疗服务时空可达性分析方法,并以武汉市中心城区为例进行了分析。试验结果表明,研究方法充分利用交通路况,兼顾了交通距离和通行时间对就医选择的影响,距离偏好在新方法中作用显著。该方法一方面可以体现不同时刻可达性差异,另一方面又强调了居民就医的时间和距离成本偏好,相比单一的时间或距离成本更具优势,分析结果更符合现实。     

“工程测量”实践教学体系的研究与构建

工程测量是港口航道与海岸工程专业技术人员必须掌握的基本技能之一。为解决应用型本科院校工程测量课程的实践教学体系与应用型人才培养目标要求不相适应的问题,从剖析实践教学过程中存在的现实问题出发,结合学校及专业实际情况,以大连海洋大学港口航道与海岸工程专业为例,提出了一套完整的、操作性强、专业特色鲜明的实践教学体系,并取得了一定的教学成果,对于普通高等学校应用型人才的培养具有重要的借鉴意义。     

人机交互策略在GIS软件用户界面设计中的研究

随着计算机技术的不断进步,用户界面设计---有效的人机交互策略变得更加重要。地理信息系统的发展要求其系统软件的设计者与开发者设计开发出更加人性化的用户界面,以提高不同领域、不同层次软件使用者的满意度。     

基于SMVF的高频雷达自适应多目标检测

针对高频雷达强海杂波和干扰环境下的多目标检测问题,结合S-method时频分布和Vitcrbi算法提出了一种多分量线性调频信号瞬时频率估计方法—SMVF法(S-method viterbi fitting),然后根据所提取的瞬时频率的直线拟合性能,提出了一种自适应多目标检测算法。实测数据的处理结果,表明了该算法在低信噪比时,与WDM法(wigncr distribution maxima) , WDV法( wigncr distribution vitcrbi)相比,估计精度提高约2000,验证了该算法的可行性和有效性。     

精密水准资料检查应注意的问题

通过对精密水准资料的二级检查,剔除其中的纰漏与错误,把一份完整、全面、优秀的资料交与上级部门。     

Mapping Wetland Areas Using Landsat-Derived NDVI and LSWI: A Case Study of West Songnen Plain,Northeast China

Increasing interest in wetlands for environmental management requires an understanding of the location, spatial extent, and configuration of the resource. The National Wetlands Inventory is the most commonly used data source for this information. However, its accuracy is limited in some contexts, such as agricultural and forested wetlands. An large number of studies have mapped wetlands worldwide from the perspective of land use and land cover change. However, information on the actual wetland planting areas annually is limited, which greatly impacts ongoing research. In this case study of the West Songnen Plain, we developed a simple algorithm for the quick mapping of wetlands by utilizing their unique physical features, such as annual display of phenological land-cover change of exposed soils, shallow flooding water, and plants from multi-temporal Landsat images. Temporal variations of the Normalized Difference Vegetation Index (NDVI) and Land Surface Water Index (LSWI) derived from Landsat images in 2010 for wetlands at different growth stages were analyzed. Results show that during the ante-tillering phase, the NDVI value (above zero) is lower than the LSWI value of paddies because of flooding of shallow water; during the reproductive and ripening phases, the NDVI value is higher than the LSWI value (above zero); and during the post-harvest wetland planting phase, the NDVI value is still higher than the LSWI value, but the LSWI value is negative. Wetland areas can be detected using one or two images in the optimum time window. The algorithm based on the difference of NDVI and LSWI values derived from Landsat images was used to extract the actual wetland planting area. Validated alongside statistical data, the algorithm showed high accuracy. Therefore, this algorithm highlights the unique features of wetlands and can help in mapping the actual wetland area annually on a regional scale. Results further indicate that the new method has a classification accuracy of 92 %. In comparison, two traditional methods based on Landsat-7/ETM registered accuracy rates of only 83 % and 87 % respectively.     

Small target extraction based on independent component analysis for hyperspectral imagery

A small target detection approach based on independent component analysis for hyperspectral data is put forward. In this algorithm, firstly the fast independent component analysis(FICA) is used to collect target information hided in high-dimensional data and projects them into low-dimensional space. Secondly, the feature images are selected with kurtosis. At last, small targets are extracted with histogram image segmentation which has been labeled by skewness.     

测量标志管理信息系统的设计与实现

本文在分析测量标志管理信息系统设计目标的基础上,提出了以ArcGIS Server为开发平台并采用Brow-ser/Server架构构建系统的设计方案,论文详细介绍了系统建设的功能设计、数据库设计和系统实现的技术创新点,基于此方案设计的管理系统进一步规范了测量标志信息的普查工作,提高了测量标志管理的工作效率,实现了测量标志信息管理数字化的需求。     

Towards an integral strategy for modelling uncertain geospatial data

This paper endeavours to put the discussion on errors and uncertainties in geographical information systems (GISs) in a more systematic way by examining the strength and weakness of discrete objects and continous fields, the two distinct schools of spatial data modelling. In doing so, it argues that neither discrete objects nor continous fields alone provide objective and complete representations of highly complex geographical phenomena, though there are good reasons for asserting that continuous fields are better suited to modelling spatial dependence, heterogeneity and fuzzines significant in geographical reality than discrete objects. Thus, there seems to be merit in adopting an integrated model incorporating analytical capabilities of fields and generalization functions of objects, for which extended TIN (triangulated irregular network) models along with their duals (Voronoi diagrams) provide a pragmatical solution.     

Investigating the land use characteristics of urban integration based on remote sensing data: experience from Guangzhou and Foshan

Abstract

Urban integration is an increasingly popular phenomenon. It is important to characterize the dynamic processes of urban integration from the perspective of geography. However, previous studies mainly focussed on the overall characteristics of a single entity and failed to consider inter-city influences. Therefore, this study aims to systematically investigate this phenomenon. Firstly, spatial clustering technique and landscape metric were used to analyze the temporal change of spatial layout. Secondly, we built multiple ring buffers of city boundary to reveal the directional differences in urban expansion. Lastly, we compared the observed land use data with the results simulated by cellular automata model. These experiments have shown that the urban expansion characteristics during the urban integration process are rather different from those of a single city, and the above methodology can effectively characterize the urban integration phenomenon. The successful example of Guangzhou–Foshan integration could also provide practical experience for other similar attempts.