950 resultados para SPRING-GIS
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水是人类生存不可或缺的资源,水环境污染问题愈来愈受到人们的重视。随着对点源污染控制能力的提高,非点源污染问题成为当前研究中的热点,而对非点源污染进行定量化研究的最直接、最有效的途径就是建立模拟模型。基于此热点问题,本文选择乌江流域(贵州境内)作为研究区,在ArcGIS 平台上建立了一个简单、快速评价流域非点源污染的方法,它考虑流域的空间异质性,且只需很少的参数。该方法用一个分辨率较高的栅格数字高程模型(DEM)将整个流域划分成100 m×100 m 的格网,计算每个栅格里产生的地表径流量和非点源污染负荷。通过模拟流域地表水流,追踪每个栅格中的水流流向,模拟非点源污染物在流域河网中的运动过程。该方法能计算一个区域水文系统年均非点源污染物的负荷,并能估算出由非点源污染在河网中产生的各污染物浓度值。 通过本项研究,能识别出流域内非点源污染严重区域,还可以快速模拟土地利用变化对流域非点源污染的影响,从而为流域今后的规划和综合治理提供科学依据。通过系统的研究,本文主要研究成果如下: 1. 建立了乌江流域(贵州境内)非点源污染数据库(空间数据库和属性数据库),这不仅有力地支撑了研究区非点源污染评价研究,同时对于在研究区开展其它方面的研究也是一个有力的支撑。 2. 基于Arc Hydro Tools 和DEM 自动提取的流域河网与1:25 万数字水系相比较,两者在总体上吻合较好,特别是两者的主干河道基本重合,这正是在DEM基于GIS 的乌江流域( 贵州境内) 非点源污染评价预处理中用AGREE 算法将主干河网与DEM 融合的效果;但也有少部分地区(地形平坦处,地形坡度≤3°或受人类活动影响较大的区域)两者存在较大差异,如将红枫湖、百花水库等湖泊水库区描述成河道了,在东干渠和西干渠处,由于人工河渠改变了水流的自然方向,使得提取河网与实际河网差别很大。 3. 以流域内的5 个水文站为子流域出口,分别描绘相应子流域,比较自动提取流域面积与实际量测结果,结果表明自动提取的子流域面积与实际量测子流域面积非常接近,相对误差在9%以内,能达到1:25 万数据的精度要求。 4. 以流域内5 个子流域的地表径流量,降雨量和土地利用百分比为输入参数,利用多元回归分析工具建立流域降雨径流模型,结果表明模拟相对误差在7%以内,证明所建降雨径流模型能满足模拟需要,模拟精度较高。 5. 流域出口处的年均非点源总氮(TN)和总磷(TP)输出通量分别为40309 ton 和2607 ton。从流域内各大支流控制的子流域来看,野济河流域由于其中的耕地面积大(占流域面积的51.21%),以3.03%的流域面积分别贡献了4.08%和3.95%的非点源总氮(TN)和总磷(TP)负荷;而湘江流域,由于其中的林地面积占主导地位(占流域面积的68.94%),以8.45%的流域面积只分别输出了6.40%和6.06%的非点源总氮(TN)和总磷(TP)负荷。因此,对非点源污染的控制要从耕地和草地着手,需要优先治理的流域为野济河流域、三岔河流域、猫跳河流域、偏岩河流域、乌江下干流流域。 6. 模拟的非点源总氮(TN)和总磷(TP)浓度值在流域上游明显大于下游。比较水质监测点浓度值与对应的模拟浓度值,可以发现在贵阳站和湘江站的观测值大大超过模拟值:贵阳站的总氮(TN)浓度观测值为9.37 mg/l,模拟值为2.94mg/l,总磷(TP)浓度观测值为0.68 mg/l,模拟值为0.19 mg/l;湘江站的总氮(TN)浓度观测值为5.77 mg/l,模拟值为1.98 mg/l,总磷(TP)浓度观测值为0.27 mg/l,模拟值为0.13 mg/l。另外在思南站的总磷(TP)的观测值也大大超过模拟值,观测值为0.44 mg/l,模拟值为0.14 mg/l。观测值与模拟值之间这种巨大的差异可能暗示在这两处存在明显的总氮(TN)点源污染。而贵阳站和湘江站刚好分别位于贵阳市和遵义市市区的下游,贵阳市和遵义市是流域内最大的两个工业城市。对于观测值小于模拟值的情况,主要有两种可能的原因:①某种土地利用类型的EMC 平均值赋得过高了,或②非点源污染物在随水流运动过程中损失了一部分,如沉淀或分解等。
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昂贵的GIS软件、空间数据缺乏与GIS操作复杂妨碍地球科学家进行空间数据表示。本文提出了解决这一问题的技术方法:分布式数据共享使集中式的空间数据得到最大利用,以容易获得数据;将面向应用的GIS功能从其它功能中分离开来,以移动代码的方式为用户提供分布式空间信息可视化服务,减少软件费用;在移动代码中,组合复杂的制图操作,提供制图工具,使操作简单化。
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该文以巢湖流域为研究对象,以生态系统健康理论为基础,将流域生态系统的结构和功能结合起来,通过遥感和地理信息系统(GIS)技术获取生态环境变化信息,监测和评价小流域单元的健康状况,分析人类活动对生态系统结构和功能变化的影响,为巢湖流域的生态管理和政策制定提供指导.论文的主要内容包括:1、从生态系统研究的发展入手,对生态系统健康研究的发展、评价指标、度量、研究尺度、评价单元选择进行了概括,提出生态系统健康评价应以结构和功能评价为基础、把人类作为生态系统的一部分,对生态系统进行动态监测.2、以压力-状态-反映指标为概念框架,设计了巢湖流域生态系统健康评价指标体系;3、利用RS和GIS技术获取巢湖流域内各个小流域的生态系统数据,解决了小流域人口和社会经济数据获取难的问题;4、基于GIS技术,对流域生态系统健康评价状况进行定量评价,在此基础上,采用典型相关分析方法,分析了人类社会经济活动变化与生态系统健康状况变化的关系;分析了小流域NDVI多年月变化与生态系统健康状况的关系.
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汞污染是全球性的环境问题.从20世纪50年代日本水俣湾汞中毒事件,到最近十年来,在北美及欧洲偏远地区的湖泊中发现鱼体汞含量超标,汞污染的研究一直受到人们的重视,是世界环境污染研究的热点之一.随着对全球汞生物地球化学循环研究工作的不断加深,对其的研究难度逐渐增加,以往单一的研究方法已难见成效.越来越多的研究者认识到,只有将地学领域中采用不同研究方法(地质、地球物理和地球化学等方法)所得到的信息,进行综合分析研究,才能更清楚的了解全球汞的生物地球化学循环.近年来计算机技术的发展,特别是GIS技术的出现,使得这一设想成为现实.地理信息系统(GIS),在一个灵活的空间数据管理环境中,将从不同方面采集、存储和分析的数据提供给用户.用户利用GIS数据中的各种相关的空间或非空间信息,进行各种综合分析研究,从而对全球汞的生物地球化学循环提出新的认识和作出科学的论断.该文偿试将地理信息系统应用在汞的生物地球化学循环研究中.论文的主要内容包括以下两部分:1)地理信息系统的核心是空间数据库,该文建立了贵州省汞地球化学数据库.应用ArcGIS中的MapObjects控件和VB技术相结合开发的贵州省汞地球化学数据库,既能充分发挥管理的优势,又能快速产生友好用户界面,具有快捷、方便、高效等特点.该数据库为贵州省汞地球化学循环研究提供了空间数据管理功能,不仅可以存储大量的空间数据和属性数据,还可以进行空间数据输入、浏览、查询、删除和输出及属性表数据的查询、分析和输出.贵州省汞地球化学数据库为政府决策部门提供了环境监测数据和决策支持系统,也有利于世界范围内汞地球化学研究数据的交流.2)应用贵州省汞地球化学数据库中的贵阳市土壤汞含量数据图,结合贵阳市土壤一大气汞交换通量数据,用多元回归的方法对贵阳市土壤向大气年排汞量进行了估算,结果为:年释汞通量为652Kg,变化范围为463~919Kgyear<'-1>.单位面积的平均释汞量为193~382gKm<'-2>year<'-1>.对比全球背景值,贵阳市土壤年释汞通量的预测值总体偏高,主要是贵阳市的亚热带气候和土壤汞含量偏高的影响.与贵阳市燃煤年排汞量相比,贵阳市土壤释汞通量为0.652tyear<'-1>,仅为目前燃煤排汞量的1/3.说明贵阳市大气汞的来源还是以人为污染为主,但被污染的土壤对大气汞也有不可忽视的贡献.
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本文以岩溶山区贵阳市为研究对象,利用多时相TM遥感数据及相关资料,结合地理信息系统技术,对贵阳市资源环境进行了初步调查与研究。论文研究内容主要包括三个部分:(1)遥感图象予处理(2)遥感图象分类(3)试验区空间数据库的建立与初步应用。通过本论文的研究,得到以下几点认识和成果:a)在岩溶山区城市能利用TM数据城市环境调查与动态研究。b)探索了一个适合于岩溶山区城市TM遥感土地分类的最佳波段组合。c)通过对TM数据土地分类结果分析。认为试验区土地利用结构不合理。d)制作了试验区一系列不同时相的遥感专题数据图件。通过这些专题图件可以得到试验区的资源环境现状及其变化趋势。e)建立了试验区实间数据库。
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本文探讨了遥感(RS)和地理信息系统(GIS)在岩溶地区水文模型中的应用情况,并结合中国-比利时政府间国际合作项目“遥感和水文模式技术在岩溶地区土地和水资源管理的应用“部分研究内容,成功地将RS,GIS应用到岩溶地区的水文模型研究中去,并到得了一系列十分有意义的成果。这是首次在国内开展这类工作,在国外将RS,GIS应用到岩溶地区的水文模型研究工作也十分鲜见,固而说论文获取的成果对岩溶地区的科研工作具有重要意义。对生产管理工作也是如此。
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Considerações básicas: A amostragem; A confecção de grades; O produto. Esquema do processo do modelo numérico de terreno do Spring.
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Geoprocessamento. Sistema de informações geográficas - SIG / SPRING. Esquema operacional. Criação e manipulação do bancos de dados. Criação do plano de informação - PI. Escolha do modelo de dados. Imagens. Modelo Numérico de Terreno - MNT. Grades regulares. Fatiamento. Objeto. Mapa cadastral. Redes. Temática.
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Análise espacial.
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Os Sistemas de Informação Geográfica (SIG) promoveram uma revolução nas operações de armazenamento e manipulação de informações espaciais e a Internet fomenta a atividade de disseminação desse tipo de informação para um público mais numeroso, heterogêneo e com diferentes interesses.
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This study aims to present the conditions related to the European Union’s involvement in the Arab Spring, as well as examine the extent of this capability-based involvement in the first months of 2011 against the background of competence disputes between institutions and inter-governmental contentions. These considerations will be the basis for conclusions on the theoretical and practical viability of the European Union’s action in the region of North Africa, in terms of both interests defined in Brussels and representation of a jointly agreed position and undertaking practical actions in the international arena. These assumptions can facilitate a new perspective for the EU’s strategic approach framework in the region of North Africa.
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PURPOSE: The role of PM10 in the development of allergic diseases remains controversial among epidemiological studies, partly due to the inability to control for spatial variations in large-scale risk factors. This study aims to investigate spatial correspondence between the level of PM10 and allergic diseases at the sub-district level in Seoul, Korea, in order to evaluate whether the impact of PM10 is observable and spatially varies across the subdistricts. METHODS: PM10 measurements at 25 monitoring stations in the city were interpolated to 424 sub-districts where annual inpatient and outpatient count data for 3 types of allergic diseases (atopic dermatitis, asthma, and allergic rhinitis) were collected. We estimated multiple ordinary least square regression models to examine the association of the PM10 level with each of the allergic diseases, controlling for various sub-district level covariates. Geographically weighted regression (GWR) models were conducted to evaluate how the impact of PM10 varies across the sub-districts. RESULTS: PM10 was found to be a significant predictor of atopic dermatitis patient count (P<0.01), with greater association when spatially interpolated at the sub-district level. No significant effect of PM10 was observed on allergic rhinitis and asthma when socioeconomic factors were controlled for. GWR models revealed spatial variation of PM10 effects on atopic dermatitis across the sub-districts in Seoul. The relationship of PM10 levels to atopic dermatitis patient counts is found to be significant only in the Gangbuk region (P<0.01), along with other covariates including average land value, poverty rate, level of education and apartment rate (P<0.01). CONCLUSIONS: Our findings imply that PM10 effects on allergic diseases might not be consistent throughout Seoul. GIS-based spatial modeling techniques could play a role in evaluating spatial variation of air pollution impacts on allergic diseases at the sub-district level, which could provide valuable guidelines for environmental and public health policymakers.
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BACKGROUND: This study examined whether objective measures of food, physical activity and built environment exposures, in home and non-home settings, contribute to children's body weight. Further, comparing GPS and GIS measures of environmental exposures along routes to and from school, we tested for evidence of selective daily mobility bias when using GPS data. METHODS: This study is a cross-sectional analysis, using objective assessments of body weight in relation to multiple environmental exposures. Data presented are from a sample of 94 school-aged children, aged 5-11 years. Children's heights and weights were measured by trained researchers, and used to calculate BMI z-scores. Participants wore a GPS device for one full week. Environmental exposures were estimated within home and school neighbourhoods, and along GIS (modelled) and GPS (actual) routes from home to school. We directly compared associations between BMI and GIS-modelled versus GPS-derived environmental exposures. The study was conducted in Mebane and Mount Airy, North Carolina, USA, in 2011. RESULTS: In adjusted regression models, greater school walkability was associated with significantly lower mean BMI. Greater home walkability was associated with increased BMI, as was greater school access to green space. Adjusted associations between BMI and route exposure characteristics were null. The use of GPS-actual route exposures did not appear to confound associations between environmental exposures and BMI in this sample. CONCLUSIONS: This study found few associations between environmental exposures in home, school and commuting domains and body weight in children. However, walkability of the school neighbourhood may be important. Of the other significant associations observed, some were in unexpected directions. Importantly, we found no evidence of selective daily mobility bias in this sample, although our study design is in need of replication in a free-living adult sample.