Spatial discretization of large watersheds and its influence on the estimation of hillslope sediment yield          下载免费PDF全文

Virginia I. González  Athena B. Carkovic  Gabriel P. Lobo  Dennis C. Flanagan  Carlos A. Bonilla 《水文研究》2016,30(1):30-39

The combined use of water erosion models and geographic information systems has facilitated soil loss estimation at the watershed scale. Tools such as the Geo‐spatial interface for the Water Erosion Prediction Project (GeoWEPP) model provide a convenient spatially distributed soil loss estimate but require discretization to identify hillslopes and channels. In GeoWEPP, the TOpographic PArameteriZation (TOPAZ) model is used as an automated procedure to extract a watershed boundary, hillslopes and channels from a digital elevation model (DEM). Previous studies in small watersheds have shown that the size of the hillslopes and the channel distribution affect the model estimates, but in large watersheds, the effects on the soil loss estimates have yet to be tested. Therefore, the objective of this study was to evaluate the effect of discretization on the hillslope sediment yield estimates using GeoWEPP in two large watersheds (>10 km²). The watersheds were selected and discretized varying the TOPAZ parameters [critical source area (CSA) and minimum source channel length (MSCL)] in a 30‐m resolution digital elevation model. The drainage networks built with TOPAZ were compared with each other using the drainage density index. The results showed that the discretization affected hillslope sediment yield estimates and their spatial distribution more than the total runoff. The drainage density index and the hillslope sediment yield were proportional but inversely related; thus, soil loss estimates were highly affected by the spatial discretization. As a result of this analysis, a method to choose the CSA and MSCL values that generates the greatest fraction of hillslopes having profile lengths less than 200 m was developed. This slope length condition is particularly crucial when using the WEPP and GeoWEPP models, in order for them to produce realistic estimates of sheet and rill erosion. Finally, and as a result of this analysis, a more reliable method was developed for selecting the TOPAZ channel network parameters (CSA and MSCL). Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

OUTREACH TO PRECOLLEGIATE AMERICAN HISTORY TEACHERS: THE UTILITY OF HISTORICAL GEOGRAPHY THEMES *     

Judith W. Meyer 《The Professional geographer》1988,40(3):326-333

The utility of introducing historical geography topics into pre-college American history courses is explored through surveys of social studies teachers in New England and at a meeting of the National Council for Geographic Education (NCGE). Many history teachers claim to use geography in their courses, but use mostly map skills, place locations, and determinism. History teachers are interested in materials and workshops on historical geography themes, however, and sample, materials were well received by teachers in attendance at a national and a regional conference.  相似文献   

APPLICATION　OF　GIS　IN　ANALYZING　ECOSYSTEM＇S　RELATIVE　SENSITIVITY　TO　ACID　DEPOSITION     

《中国地理科学(英文版)》1996,(4)

ＡＰＰＬＩＣＡＴＩＯＮ　ＯＦ　ＧＩＳ　ＩＮ　ＡＮＡＬＹＺＩＮＧ　ＥＣＯＳＹＳＴＥＭ＇Ｓ　ＲＥＬＡＴＩＶＥ　ＳＥＮＳＩＴＩＶＩＴＹ　ＴＯ　ＡＣＩＤ　ＤＥＰＯＳＩＴＩＯＮＡＰＰＬＩＣＡＴＩＯＮＯＦＧＩＳＩＮＡＮＡＬＹＺＩＮＧＥＣＯＳＹＳＴＥＭ＇ＳＲＥＬＡ...  相似文献   

Spatial autocorrelation as a criterion for retaining factors in ordinations of geographic data     

Daniel Wartenberg 《Mathematical Geology》1985,17(7):665-682

  相似文献   

地理环境对黄梅戏影响的初步研究   总被引：6，自引：0，他引：6  

夏玢 《云南地理环境研究》2006,18(2):107-110

黄梅戏是安徽省重要的文化资源。它以优美的唱腔、鲜活的人物、灵动的表演和通俗的故事情节，赢得了人们的关注，在中国戏曲舞台上占据重要的地位。在它产生、传播、成长和发展的每一个阶段，自然环境和社会环境都对它产生不同程度的影响。与此同时，地理环境通过直接影响创作者的认知方式，进而问接影响黄梅戏艺术特色，最终使黄梅戏艺术烙上了成长之地地理环境众多因子的印记。  相似文献   

Slope Instability Zonation: a Comparison Between Certainty Factor and Fuzzy Dempster–Shafer Approaches     

Binaghi  E.  Luzi  L.  Madella  P.  Pergalani  F.  Rampini  A. 《Natural Hazards》1998,17(1):77-97

This paper presents a comparison between two methodologies for the evaluation of slope instability and the production of instability maps, using a probabilistic approach and a hybrid possibilistic and credibilistic approach. The first is the Certainty Factor method, and the second is based on Fuzzy Logic integrated with the Dempster–Shafer theory. These methodologies are applied to the 1 : 50,000 scale Fabriano (Marche, Italy) geological map sheet. The results are represented as histograms where the accuracy of the prediction is shown, and the comparison of the results of the methods is discussed.  相似文献   

地理信息系统的基本技术与发展动态   总被引：153，自引：8，他引：145       下载免费PDF全文

吴信才 《地球科学》1998,23(4):329-333

从结构功能上分析了地理信息系统的概念及主要研究的内容,并且对当前地信息系统研究中的几个热点研究领域,如面向对象技术、三维技术、图象处理和人工智能技术等作了简要介绍。  相似文献   

地理信息系统中地图出版的彩色处理   总被引：1，自引：0，他引：1       下载免费PDF全文

谢忠 《地球科学》1998,23(4):334-336

分析了彩色地图出版中彩色处理的特点和关键问题,提出以印刷为中心、增加专色描述的方案针对这个方案实现的两个关键问题,提出了相庆的色差矫正和专色处理的解决方案和流程。  相似文献   

MAPGIS二次开发库的设计与实现简介   总被引：27，自引：5，他引：22       下载免费PDF全文

周顺平 《地球科学》1998,23(4):337-340

ＭＡＰＧＩＳ系统不仅是一个ＧＩＳ基础软件,而且是用户开发面向具体领域的ＧＩＳ的工具,在分析对比ＧＩＳ空间模型的基础上,从空间实体模型分析、二次开发函数库软件结构设计、函数的功能分类、的实现几个方面。  相似文献   

GPS移动目标实时监控系统的设计与实现   总被引：2，自引：0，他引：2       下载免费PDF全文

龚国清 《地球科学》1998,23(4):412-414

随着计算机科学技术的发展,ＧＩＳ,ＧＰＳ技术越来越多地被人们所重视,并已经被广泛应用到诸多领域．简述了对移动目标监控系统的总体结构设计,着重介绍了软件的开发以及系统的功能,最后扼要地说明了移动目标实时监控系统的应用情况．  相似文献