INTEGRATED VEGETATION CLASSIFICATION AND MAPPINGUSING REMOTE SENSING AND GIS TECHNIQUES

NOAA-AVHRR data have been more and more used by scientists because of its short temporal resolution,large scope, inexpensive cost and broad wave bands. On macro and middle scale of vegetation remote sensing, NOAAAVHRR possesses an advantage when compared with other satellites. However, because NOAA-AVHRR also problem of low resolution, data distortion and geometrical distortion, in the area of application of NOAA-AVHRR in largescale vegetation - mapping, the accuracy of vegetation classification should be improved. This paper discuss the feasibilityof integrating the geographic data in GIS(Geographical Information System) and remotely sensed data in GIS. Under theenvironment of GIS, temperature, precipitation and elevation, which serve as main factors affecting vegetation growth,were processed by a mathematical model and qualified into geographic image under a certain grid system. The geographicimage were overlaid to the NOAA-AVHRR data which had been compressed and processed. In order to evaluate the usefulness of geographic data for vegetation classification, the area under study was digitally classified by two groups of interpreter: the proposed methodology using maximum likelihood classification assisted by the geographic database and a conventional maximum likelihood classification only. Both result were compared using Kappa statistics. The indices to both theproposed and the conventional digital classification methodology were 0. 668(yew good) and 0. 563(good), respetively.The geographic database rendered an improvement over the conventional digital classification. Furthermore, in this study,some problems related to multi-sources data integration are also discussed.

Dynamic analysis of mainstream area and vegetation coverage degree of Songhua River based on RS and GIS techniques

Based on remote sensing technique,using 1990's Landsat TM data and 2000's Landsat ETM data,the authors conducts the comparative study of mainstream area of Songhua River by means of human-computer inter-action method.The results show that the area of Songhua River mainstream was 738 102 km 2 in 1990,and was 810.451 km 2 in 2000.From 1990 to 2000,the increased area of river mainstream is up to 72.349 km2 due to soil erosion and water loss.Meanwhile,the dynamic changes of surrounding vegetation cover are also studied.It is estimated that the trend of surrounding soil erosion and water loss of Songhua River mainstream becomes worse in Jilin Province.

Diachronic Study of the Vegetation Covers Spatiotemporal Change Using GIS and Remote Sensing in the Ferkla Oasis: Case Study, Bour El Khourbat, Tinjdad, Morocco

The Oasis of Ferkla is part of the Oases of Tafilalt in southern Morocco. These are classified by UNESCO as the Oases of Southern Morocco Biosphere Reserve. The Ferkla Oasis is increasingly experiencing a situation of increased regression and degradation, aggravated by the effects of climate change. These foreshadow a considerable acceleration of desertification and drought with the effect of the loss of production systems whose social, ecological and economic role remains major for the whole country. In order to contribute to a better understanding of the dynamics of the vegetation in this territory and the impact of climate change in the Oasis of Ferkla, we used spatial remote sensing to trace the evolution of changes in the vegetation cover in an agricultural extension called Bour El Khourbat. Calculation of the Normalized Difference Vegetation Index for seven multidate satellite images allowed us to follow the vegetation in this oasis zone from the year 1984 to 2019. Indeed, from these multi-temporal images, this study clearly shows the evolution of the vegetation with a remarkable agricultural extension towards the South-East of the zone. This extension is due not only to the installation of a diversion dam upstream but also to the development of the localized irrigation system “Drop by Drop” which is a technique that saves water resources in addition to the presence in the area. Bour El Khourbat specifies a geological structure, in the primary, relatively favorable to having water linked to cracks.

VEGETATION MAPPING USING REMOTE SENSING AND GIS

Classification accuracy of satellite imagery in complex terrain environments can be improvd by using ancillary daa and imasery spaial features extracted from the images. The classification mny be accomplished by using spaial analysis methods of geographic information System (GIS) that provide a tool for integrating all Kinds of ancillare data, or using ancillare data as an augmented subset of bands in processing imagery. The purpose of the study is to test the role of GIS spatial and spectra analysis medel in aiding the classification of satellite data and to compare the ability Of two satellite systems, SPOT and Landsat Thematic Mapper (TM) in vegetation mapping in mountainous region.

基于RS与GIS方法的海南植被变化分析

遥感和地理信息系统技术的发展为研究植被变化提供了有效手段 .该文以 1987年海南植被类型分布图和1998年的TM遥感资料为信息源 ,综合GIS参与监督分类及目视判读的方法 ,以GIS为工具对海南岛的植被变化进行了分析研究 .结果表明 ,海南岛建省后人类活动对森林生态系统影响加剧 ,人工植被面积明显增加 ,但空间差异大 ;自然植被面积减少 ,边缘线在向中部山区退缩 。

Using multispectral landsat and sentinel-2 satellite data to investigate vegetation change at Mount St. Helens since the great volcanic eruption in 1980

Long-term analyses of vegetation succession after catastrophic events are of high interest for an improved understanding of succession dynamics. However, in many studies such analyses were restricted to plot-based measurements. Contrarily, spatially continuous observations of succession dynamics over extended areas and timeperiods are sparse. Here, we applied a change vector analysis(CVA) to investigate vegetation succession dynamics at Mount St. Helens after the great volcanic eruption in 1980 using Landsat. We additionally applied a supervised random forest classification using Sentinel-2 data to map the currently prevailing vegetation types. Change vector analysis was performed with the normalized difference vegetation index(NDVI) and the urban index(UI) for three subsequent decades after the eruption as well as for the whole observation time between 1984 and 2016. The influence of topography on the current vegetation distribution was examined by comparing altitude, slope angles and aspect values of vegetation classes derived by the random forest classification. WilcoxRank-Sum test was applied to test for significant differences between topographic properties of the vegetation classes inside and outside of the areas affected by the eruption. For the full time period, a total area of 516 km2 was identified as re-vegetated, whereas the area and magnitude of re-growing vegetation decreased during the three decades and migrated closer to the volcanic crater. Vegetation losses were mainly observed in regions unaffected by the eruption and related mostly to timber harvesting. The vegetation type classification reached a high overall accuracy of approximately 90%. 36 years after the eruption, coniferous and deciduous trees have established at formerly devastated areas dominating with a proportion of 66%, whereas shrubs are more abundant in riparian zones. Sparse vegetation dominates at regions very close to the crater. Elevation was found to have a great influence on the reestablishment and distribution of the vegetation classes within the devastated areas showing in almost all cases significant differences in altitude distribution. Slope was less important for the different classes-only representing significantly higher values for meadows, whereas aspect seems to have no notable influence on the reestablishment of vegetation at Mount St. Helens. We conclude that major vegetation succession dynamics after catastrophic events can be assessed and characterized over large areas from freely available remote sensing data and hence contribute to an improved understanding of succession dynamics.

基于RS和GIS的大渡河上游植被覆盖时空变化

【目的】在RS和GIS技术的支持下,对大渡河上游丹巴段1989—2012年的植被覆盖状况及时空变化特征进行分析研究,为区域生态环境保护和建设提供理论依据。【方法】以1989,2000和2012年3期TM遥感影像和ASTER GDEM数字高程模型为数据源,首先运用RS软件计算提取研究区3个时期基于TM影像的归一化植被指数的植被覆盖度图和基于ASTER GDEM数字高程模型的海拔、坡度、坡向地形因子图;然后在Arc GIS软件平台下,对植被覆盖度图及3种地形因子图进行等级划分;最后将对应年份的植被覆盖度等级图分别与海拔等级图、坡度等级图、坡向等级图进行叠加,统计分析获得3个时期的植被覆盖状况及时空变化特征。【结果】1989,2000和2012年3个年份的植被覆盖度fc≥0.5的区域面积比例均达研究区总面积的58%以上;1989—2012年间Ⅰ级（fc≥0.7）和Ⅱ级（0.5≤fc〈0.7）植被覆盖度区域面积分别减少2.98%和4.72%,而Ⅲ级（0.3≤fc〈0.5）、Ⅳ级（0.15≤fc〈0.3）和V级（fc〈0.15）植被覆盖度区域面积分别增加10.88%,1.22%和9.39%;不同时段研究区植被覆盖度呈现出不同的变化特征,其中,1989—2000年,由于人为砍伐和过度放牧等原因,植被覆盖度整体呈下降趋势,2000—2012年,由于退耕还林和天然林保护工程,植被覆盖度整体呈上升趋势。不同海拔、坡度和坡向地带植被覆盖具有不同的分布和变化特征,植被覆盖度较高的区域主要分布在海拔2 500~4 500 m以及坡度30°~45°的地带,而海拔〈2 500 m、〉4 500 m和坡度〈30°的地带,植被覆盖度相对较低;不同坡向植被覆盖呈现出半阳坡〉阳坡〉半阴坡〉阴坡的特征。植被覆盖变化较为明显的区域集中海拔〈2 500 m和坡度〈30°的地带,海拔〉4 500 m和坡度〉45°的地带受人为活动影响小,植被覆盖变化不明显。【结论】1989—2012年间研究区植被覆盖状况较好,但总体呈现降低的变化特征;研究区植被覆盖状况受海拔、坡度和坡向等地形因子和人类活动等2方面因素影响较大。因此,森林资源的保护一方面要加强退耕还林、天然林保护等措施的力度,另一方面也应利用有利的地形来提高和改善植被覆盖状况,以避免研究区植被覆盖度逐渐降低。

基于RS和GIS的毛乌素沙地植被盖度定量估测

选取毛乌素沙地东北部的伊金霍洛旗为研究区域,以少量野外定位调查数据与其对应的遥感信息和GIS信息为基础,利用岭估计分析方法,对植被盖度估测模型及其影响因子进行系统研究.结果表明,植被盖度除受NDVI影响外,还与其他遥感信息紧密相关,岭估计方法明显地改善了最小二乘估计的缺陷,克服了变量间由于存在复共线性关系对求解待定参数所造成的不利影响,提高了估测精度.建立了以像元为单位的植被盖度估测模型,其模型检验精度达98.7%.此外,还建立了区域性植被盖度地理信息系统,实现了研究区域内任意一点(像元)或任意土地单元植被盖度的查询、更新及自动制图.

基于RS和GIS的中国西北不同生态类型区生态环境时空变化研究

采用定性与定量相结合的方法,在遥感(RS)和地理信息系统(GIS)支持下,利用1982-2000年的空间分辩率为8 km×8 km的NDVI数据(由NOAA-AVHRR提供)和地面气象资料,联合分析西北不同生态类型区生态环境的变化过程,得出中国西北地区NDVI的年平均值及其历年变化曲线、NDVI年平均值分布图和每隔10 a的差值变化图。由此可以看出,生态环境变化时空特点明显:20世纪80年代生态环境的变化波动不大,90年代以来波动变化明显,而且从1998年以后生态环境总体呈下降趋势;不同生态类型区植被指数年际变化的驱动因子不同,黄土高原区植被指数年际变化与降水量的相关性显著,而青藏高原高寒区与气温的相关性显著,其他分区与降水量和气温的相关性都不显著;生态环境变化的地域差异性明显,西北不同生态类型区中生态环境由好到差依次是陕南-陇南湿润半湿润区、黄土高原区、青藏高原高寒区、干旱区。四个分区1990年比1982年生态环境有所提高,但干旱区退化面积较大,2000年与1990年相比,生态环境都出现不同程度的退化,其中,陕南-陇南湿润半湿润区退化面积最大,其次是黄土高原区。整体生态环境状况不佳,而且近年的退化应该引起重视。

基于RS和GIS分析干旱区土地利用/覆盖变化对陆地植被碳储量的影响——以新疆鄯善县绿洲为例

土地利用馒被变化是影响陆地碳循环的一个重要因子。依据鄯善平原绿洲群1990、1999两年9月TM与SPOT4（P）的融合影像以及2004年9月SPOT5（XS／XI）影像数据，采用混合分类法对研究区土地覆被进行分类，估算其变化面积以及林地与各土地覆被类型的面积转换。结果显示：1990～1999年、1999～2004年研究区林地面积年变化率分别为＋4．59％、-1．70％，植被碳库1999年比1990年增加了264．13×10^3t，2004年较之1999年减少了70．75×10^3t，但2004年植被碳储量较1990年上升212．04×10^3t，研究区总体上为一小的净碳汇。15a间天然草地的植被碳储量一直下降，并在后期呈现更为严峻的态势。说明在极端干旱区，生态系统的稳定仍面临极大挑战。如何实现丰富矿产资源的开采与人居生存环境相协调，做好土地、水资源管理与生态环境保护工作，仍需更为深入、审慎的研究。

基于RS与GIS地震灾害后森林植被重建的关键技术探讨

简要分析地震灾害对森林植被造成的破坏,指出森林植被灾后重建的必要性和重要性。探讨分析RS与GIS技术在地震灾害后森林植被重建中林区道路选址与区划、森林植被受害状况统计、生产恢复条件调查、林地适宜性评价与树种选择、森林植被空间优化配置及恢复评价等方面的重要作用,以期为灾后森林植被的重建工作提供理论参考与技术支持。

基于RS和GIS的毛乌素沙地荒漠化程度定量估测

选取内蒙古自治区毛乌素沙地东北部伊金霍洛旗为研究区域,以少量野外定位调查数据与其对应的RS和GIS信息为基础,利用主成分分析、因子分析和多元线性回归分析方法,建立以像元为单位的植被盖度和生物量的定量估测模型。通过对数学模型的分析,得到影响植被盖度和生物量的主要指标(因子)。在对荒漠化程度量化分级后,建立以植被盖度和生物量2个重要指标为影响因子的荒漠化程度定量估测模型,实现区域性荒漠化程度的定量估测。

运用RS和GIS进行植被覆盖分级研究——以重庆合川市为例

RS和GIS技术的发展为研究植被覆盖信息提供了有效手段,该文以重庆合川市为例,以TM图像资料为信息源,结合GIS管理工具进行了植被覆盖分级研究。研究结果表明合川市植被覆盖分布不均,植被覆盖分级属于较低等级。这一研究对确定水土流失强度等级具有十分重要的意义,有助于政府部门制定防止植被退化和水土流失的相应对策。

基于RS、GIS重庆市都市圈生态绿地特征研究

在TM影像的基础上,应用REDAS和GIS软件,对重庆市都市区的绿地生态进行了研究。为了提取正确的生态绿地专题信息,对TM影像进行了波段组合从而完成解译、监督分类,导入GIS软件进行绿地属性信息的提取。分析了重庆绿地的总体情况,并提出了一定的建议。

基于RS/GIS公路路域水土流失动态变化的研究——以榆靖高速公路为例

基于RS数据源,利用ERDAS和ArcG IS软件技术,对榆靖高速公路两侧300 m范围水土流失动态变化开展研究。通过遥感图像数字处理方法,提取对水土流失起主导作用的植被覆盖度、土地利用类型、沟谷密度等因子;在矢量化等高线数据的基础上生成数字高程模型(DEM),提取地形坡度因子,将这4个因子在G IS中进行空间叠加分析。参照《土壤侵蚀分级标准》,生成研究区不同时段水土流失强度等级图,利用G IS属性统计功能对公路沿线各等级水土流失区面积进行统计,参照研究区不同侵蚀类型的土壤侵蚀模数,得出1996年和2006年公路沿线各流失区的水土流失量,并对公路沿线水土流失动态变化进行分析。结果表明:榆靖高速公路修建后沿线600 m范围水土流失总量减少19.26万t/a,水土流失呈减弱趋势。公路施工期导致水土流失增强的各种因素随着营运期固化路面的形成而逐渐消失,防沙固沙和生态恢复等措施有效改善了公路路域生态环境,对公路沿线水土流失防治起到了积极作用。

基于RS、GIS重庆市都市区生态绿地分析

基于TM影像的基础上,应用REDAS和GIS软件,对重庆市都市区的绿地生态进行了研究.为了提取正确的生态绿地专题信息,对TM影像进行了波段组合从而进行解译,监督分类,导入GIS软件进行绿地属性信息的提取,分析了重庆绿地的总体情况,并提出了一定的建议.

基于RS与GIS密云区植被盖度动态演变及其预测研究

基于RS和GIS技术,以密云区2001年和2010年两期Landsat TM5遥感影像为主要数据源,在定量反演研究区归一化植被指数(NDVI)基础上,研究该区域植被覆盖度并分析其时空演变,并基于马尔科夫模型完成其植被盖度动态预测。结果表明:密云区整体植被状况较好,中高覆盖和高盖度植被是研究区植被覆盖的主体,占总面积89.39%,近10 a密云区植被盖度总体呈上升趋势,高盖度面积增加448.87 km^2,其它类型的植被盖度面积减少,中高盖度植被面积减少最大,为401.01 km^2,且植被盖度重心总体向高覆盖度移动。基于马尔科夫模型的预测发到2091年,各植被类型的面积比例达到相对稳定状态,分别为0.48%、1.75%、2.68%、6.94%和88.15%,高盖度植被占据绝对的优势地位。

基于RS和GIS的农作物估产方法研究进展

实时获取农作物长势及产量等信息对于现代农业的发展具有重要意义。近年来,随着遥感技术(remote sensing,RS)和地理信息系统(geographic information system,GIS)广泛应用于农作物估产领域,相继出现了一些较为实用的估产方法,主要有结合辅助数据的估产方法、基于植被指数的估产方法、基于特定模型的估产方法和基于农作物估产平台(软件)的开发等。其中,基于植被指数的估产方法又分为单一和多植被指数估产2类方法。在对近年来该领域大量文献深入研究的基础上,着重就几类热点方法展开论述,并对每类方法的优势和缺陷进行了评述,最后对该领域需要进一步研究的方向进行了探讨和展望,以期为后续研究提供参考。

基于RS与GIS的太行山山地丘陵区水土流失风险评价——以河北省赞皇县为例

太行山山地丘陵区由于地形、地貌、气候等自然条件和人类活动的干扰,出现了一定程度的水土流失。本文以河北省赞皇县为例,选取美国陆地卫星2010年Landsat5TM遥感影像、DEM数据和土地利用现状等数据,在RS和GIS的技术支持下,提取对水土流失影响较大的植被覆盖度、地形坡度和土地利用类型等因子,对赞皇县水土流失强度进行等级划分。结果表明:赞皇县水土流失程度有微度、轻度、中度、强度、极强度和剧烈几种情况,其中以微度、轻度和中度为主,分别占土地总面积的69.27%、19.30%和10.86%,主要集中分布于自然保留地、旱地和园地。

基于RS&GIS的西部干旱区植被覆盖变化的研究

以新疆阜康地区为研究区,利用遥感和GIS技术及数理统计学方法,利用ERDAS软件,通过对70年代MSS和2000年ETM影象的几何校正、图象增强、应用目视解译方法,在地理信息系统软件ArcGIS中编制两期生态景观图,利用矢栅转换和叠置功能来研究土地及植被类型的面积及空间分布状况在两期图中的变化,并通过土地利用与土地覆被变化来研究70年代到2000年西部干旱区土地及植被类型变化过程和趋势。