基于GIS的黑龙江省区域奶牛分布信息系统的设计与实现

为了对黑龙江省区域奶牛养殖的信息及饲养状况进行现状调查,采用GIS控件MapObjects嵌入VisualBasic进行二次开发的方法,编制一套既有数据管理功能又有图形管理功能的地理信息系统,使用本系统做出统计分析,可以直观的得到某区域内奶牛的信息,有利于对奶牛进行有效的管理,有利于畜牧局和相关企业对区域进行规划和建设,提高奶牛饲养、管理工作的科学化程度。     

Suitability of transport equations in modelling soil erosion for a small Loess Plateau catchment

Erosion models have not often been applied to very steep terrain such as the gully catchments of the Chinese Loess Plateau. The purpose of this research was to evaluate the suitability of a number of transport equations for use in erosion modelling under Loess Plateau conditions. To do this the equations were programmed into the LISEM model, which was applied to the 3.5 km² Danangou catchment in the rolling hills region of the Loess Plateau. Previous evaluations of transport equations used either flume tests or river sections, and did no spatial modelling. The results show that some equations predicted physically impossible concentrations (defined as above 1060 g/l). The results were evaluated by using two methods: 1) by comparing predicted and measured sedigraphs and sediment yield at the catchment outlet, and 2) by comparing the fraction of the catchment in which physically impossible transport capacities occurred. The results indicated that for the small grain sizes, high density flows and steep slopes of the gully catchments on the Loess Plateau the Shields parameter attained very high values. Furthermore, the transport threshold can usually be neglected in the equations. Most of the resulting equations were too sensitive to slope angle (Abrahams, Schoklitsch, Yalin, Bagnold, Low and Rickenmann), so that transport rates were overpredicted for steep slopes and underpredicted for gentle slopes. The Yang equation appeared to be too sensitive to grainsize. The Govers equation performed best, mainly because of its low slope dependency, and is therefore recommended for erosion models that simulate sediment transport by flowing water in conditions with small grain sizes and steep slopes.     

SEDIMENT TRANSPORT EXPERIMENTSIN UNSTEADY FLOWS

l INTRODUCTIONThe theories and formulas of sediment dynamics were established based on steady and uniform flows.These theories and formulas often fail to aPply in engineering projects because, in nthee, sediment istransported often by unsteady and non-uniform fiows (Wang et al., l997).TWo cases ofnon-stationarity can be distinguished f long-tertn and short-term (Plate, l994). Long-termnon-stationarity tfansport can be defined as a sediment process which can be treated by sequences ofstat…     

区域经济地理学理论方法建设简论

长期以来,中国区域经济地理学基本上是沿着就空间论空间,就经济论经济,就布局论布局的道路走过来的。10年改革,使学科获得了显著发展。今后的任务似应在实践基础上进一步加强理论方法建设。在理论上,把就空间论空间的区域观念转变为时空统一的区域观念;在内容上,从就经济论经济,就布局论布局扩展到以经济为主体,以自然和社会为两翼的广泛领域;在方法上,从分析——综合转变为全方位(综合——分析——综合)的综合。同时,加强指标体系的建设;重视对区域本质特征、即区域个性的研究,通过把握区域运动的主要矛盾,促进其合乎规律地发展.     

论现代地理学对象、内容、结构和基本方法

本文从地理学对象及其性质的讨论出发,详细阐述了地理学内容、结构和它的基本方法。     

基于MapXtreme的校园WebGIS系统实现

万维网地理信息系统(WebGIS)是利用互联网(Internet)来扩展和完善地理信息系统功能的一项新技术，是由地理信息系统和互联网技术相结合而产生的一种新方法。目前，用于开发WebGIS的方法有许多种，文章研究基于MapXtreme的WebGIS实现方法，把MapXtreme与JavaScript及ASP相结合开发WebGIS系统，并将其应用于校园信息查询中。实现基于MapXtreme的校园WebGIS系统。     

地理标记语言到VML的转换

分析了地理标记语言和矢量标记语言的各自特征，在此基础之上提出了一种从GML格式转换到VML格式的方法，实现了IE中矢量地图的直接显示。最后给出了实例验证。     

DXF格式地理空间实体的GML表示

在详细研究DXF文件格式和地理标识语言(GML)的基础上，实现了DXF格式空间实体的GML表示，为实现互联网环境下地理空间信息的共享和互操作提供了新的途径。     

全新的GIS体系结构模式:g.net

.net是微软提出的新一代因特网模型，介绍了基于.net模型的全新GIS体系结构g.net，着重地阐述了g.net的关键技术XML,g.net的结构和g.net上的数据源，展望了g.net的应用前景。     

我国经济地理学研究存在的问题及其改造途径

在分析中国经济地理学研究存在问题的基础上，对经济地理学今后发展提出了若干建议 ，开展现代自然过程及其驱动力研究，促进地理学各分支学科的高层次综合，完善并发展地理学基础,理论，逐步走向国际科学研究前沿；面向国家宏观决策需要，开展与可持续发展有关的政策性研究，高度重视研究方法，手段的更新，提高经济地理学研究的科学性，引进相关学科人才，促进学科交叉，是经济地理学发展的捷径，面向社会需求，开展区域规划与产业布局研究。