Abiotic predictors of fine sediment accumulation in lowland rivers     

Morwenna McKenzie  Judy England  Ian D.L.Foster  Martin A.Wilkes 《国际泥沙研究》2022,37(1):128-137

The delivery of excessive fine sediment (particles<2 mm in diameter) to rivers can cause serious deleterious effects to aquatic ecosystems and is widely acknowledged to be one of the leading contributors to the degradation of rivers globally.Despite advances in using biological methods as a proxy,physical measures remain an important method through which fine sediment can be quantified.The aim of this study was to provide further insights into the environmental variables controlling sediment ...  相似文献   

New vegetation type map of India prepared using satellite remote sensing: Comparison with global vegetation maps and utilities     

《International Journal of Applied Earth Observation and Geoinformation》2015

A seamless vegetation type map of India (scale 1: 50,000) prepared using medium-resolution IRS LISS-III images is presented. The map was created using an on-screen visual interpretation technique and has an accuracy of 90%, as assessed using 15,565 ground control points. India has hitherto been using potential vegetation/forest type map prepared by Champion and Seth in 1968. We characterized and mapped further the vegetation type distribution in the country in terms of occurrence and distribution, area occupancy, percentage of protected area (PA) covered by each vegetation type, range of elevation, mean annual temperature and precipitation over the past 100 years. A remote sensing-amenable hierarchical classification scheme that accommodates natural and semi-natural systems was conceptualized, and the natural vegetation was classified into forests, scrub/shrub lands and grasslands on the basis of extent of vegetation cover. We discuss the distribution and potential utility of the vegetation type map in a broad range of ecological, climatic and conservation applications from global, national and local perspectives. We used 15,565 ground control points to assess the accuracy of products available globally (i.e., GlobCover, Holdridge’s life zone map and potential natural vegetation (PNV) maps). Hence we recommend that the map prepared herein be used widely. This vegetation type map is the most comprehensive one developed for India so far. It was prepared using 23.5 m seasonal satellite remote sensing data, field samples and information relating to the biogeography, climate and soil. The digital map is now available through a web portal (http://bis.iirs.gov.in).  相似文献   

Measuring visual pollution by outdoor advertisements in an urban street using intervisibilty analysis and public surveys     

Szymon Chmielewski  Danbi J. Lee  Piotr Tompalski  Tadeusz J. Chmielewski  Piotr Wężyk 《International journal of geographical information science》2016,30(4):801-818

Debates on the encroaching commercialization of public space by outdoor advertising highlight its possible negative impact on local quality of life and enjoyment of public spaces. These overstimulating outdoor advertisements are often considered a source of visual pollution, but cities have no standard way of measuring where it exists and its local impact, and thus cannot regulate it effectively. This study illustrates that visual pollution can be measured in a useful way by relating public opinion to the number of visible advertisements (intervisibility analysis). Using a 2.5D outdoor advertisement (OA) dataset (location and height) of a busy urban street in Lublin, Poland, this preliminary experiment translates visibility into visual pollution. It was found that streetscape views with more than seven visible OAs created visual pollution in this case study. The GIS-based methodology proposed could provide Lublin officials with a basic tool to assess and manage visual pollution, by informing permitting decisions on OAs.  相似文献   

基于掌上电脑（PDA）的水准测量电子手簿研究与关键技术开发     

周奕君  童小华 《东北测绘》2008,31(1):17-20,28

在阐述水准测量及其成果整理的基础上,本文着重探讨了基于掌上电脑（PDA）的水准测量电子手簿开发的基本原理和方法,提出了以嵌入式Visual Basic开发水准测量电子手簿的基本结构框架,同时对开发中的关键技术进行了系统研究,包括测量数据的自动化处理以及Pocket Access数据库的使用等。在此基础上,以联想天玑XP100系列掌上电脑（PDA）为例,介绍了笔者开发的基于PDA的水准测量电子手簿,通过实例阐明了其应用过程。应用结果表明,本电子手簿在测量过程中具有实用意义。  相似文献   

钻井液流变模型的优选     

童红梅  乌效鸣  钮洪亮 《岩土钻凿工程》2008,(5):1-4

选择合适的工程浆液流变模型是现场生产中很重要的技术问题。基于最小二乘法原理利用Visual C＋＋高级语言编制程序对试验数据进行拟合,可求得实测浆液的常用流变参数值,绘制各常用流变模式与实际流型的曲线,从而优选出最合适的流变模式。  相似文献   

基于MO的校园地理信息系统的设计与实现     

刘向铜  熊助国  曹秋香  刘荣 《地理空间信息》2008,6(6):34-36

以Visual Basic为平台,嵌入Map Objects组件,对校园地理信息系统进行了设计与开发,实现了校园地理信息系统的漫游、查询、介绍等功能。以期地理信息系统在校园数字化建设中发挥作用。  相似文献   

基于掌上电脑(PDA)的水准测量电子手簿研究与关键技术开发   总被引：3，自引：0，他引：3  

周奕君  童小华 《测绘与空间地理信息》2008,31(1):17-20

在阐述水准测量及其成果整理的基础上,本文着重探讨了基于掌上电脑(PDA)的水准测量电子手簿开发的基本原理和方法,提出了以嵌入式Visual Basic开发水准测量电子手簿的基本结构框架,同时对开发中的关键技术进行了系统研究,包括测量数据的自动化处理以及Pocket Access数据库的使用等。在此基础上,以联想天玑XP100系列掌上电脑(PDA)为例,介绍了笔者开发的基于PDA的水准测量电子手簿,通过实例阐明了其应用过程。应用结果表明,本电子手簿在测量过程中具有实用意义。  相似文献   

Corel DRAW在测井报告成图中的应用     

张明波  毛宝安 《中国煤炭地质》2008,20(3):72-73

采用CLGIS软件的测井资料由于其输出格式及种类的局限性限制,不能同时把测井成果图做在一张图纸上．为此利用Corel DRAW平面设计软件中的VISUAL basic语言编制了测井曲线绘制程序,解决了clgis出图单一的问题,并且可以将勘探线剖面上的多条测井曲线绘制于一张图上。具有操作简单,易学,制图速度快,使用灵活等特点,在吉林省重点勘探项目上得以应用,取得好的效果,受到地质报告评审专家们的好评。  相似文献   

高速铁路综合图的自动生成和输出     

程耀东  程璐  谭冬生 《测绘科学》2016,41(11):166-170

针对普铁综合图绘制系统无法实现高铁双线并行综合图的绘制问题,提出了高铁综合图自动生成和输出的方法。通过在Auto LISP中使用ActiveX对象与Microsoft Excel对象,实现了Excel数据文件的导入和数据转换;基于高铁综合图信息,以Visual LISP语言实现了高铁综合图的自动生成;采用图形裁剪算法,实现了长条形综合图的自动分幅;运用虚拟打印技术,实现了分幅图的批量打印或PDF文件生成。实验结果表明:所提方法不仅可以快速高效地进行数据处理和综合图自动生成,还能准确地进行图形自动分幅和输出。研究结果对铁路基础设施、综合维修、列车运行等方面的信息化研究具有重要的参考价值。  相似文献   

CorelDRAW软件的二次开发在地图制图中的应用与实例   总被引：1，自引：0，他引：1  

曾克明 《测绘通报》2010,(8)

针对CorelDRAW软件在地图制作时符号的输入、修改替换和特种线型的输入、缩放的绘制工作量大等难点,应用一次程序开发功能,较好地解决了生产过程中遇到的上述问题,并举例说明符号替换和河流粗细变化程序的基本思路和部分源程序设计方法实例.  相似文献