应用MSS数字图像处理进行森林资源动态监测的探讨

本文探讨了应用多时相Landsat Mss图像进行森林动态监测的方法。研究了差值图像法、比值植被指数差值法、归一化植被指数差值法、多时相主分量分析法(垂直植被指数法)和分类比较法对提取森林动态变化信息的作用。结果表明,3种植被指数法都能较好地提取植被动态信息,可用于森林面积消长的动态监测。     

基于遥感技术的汪清县森林资源动态监测研究与实践

以吉林省汪清县为研究区,根据地理国情普查成果应用及监测工作通知要求,探讨了遥感技术在汪清县森林资源监测应用上的主要内容和方法。利用吉林省地理国情普查、基础测绘成果数据,结合Landsat、SPOT、ALOS等卫星影像数据,进行汪清县土地覆盖信息提取及动态监测、森林类型提取及动态监测、植被覆盖度提取及动态监测、森林参数模型反演及动态监测、驱动因子选取等内容进行了详细地说明,同时,针对汪清县森林资源各项的动态变化情况进行了驱动力分析。     

基于"3S"的梵净山自然保护区植被分布探讨

利用“3S”技术对梵净山国家自然保护区森林植被类型的空间分布进行分析,并为森林植被的监测与管理提供依据,更好地对各个区域(核心区、缓冲区、影响区)危害因子进行监控,从而有效地对其森林植被进行有效的保护。     

基于时间序列统计特性的森林变化监测

森林动态变化分析对揭示生态系统环境变化及植被恢复和布局重建等具有重要意义,时间序列的遥感数据为森林监测提供了基础数据。本文根据森林植被的统计学特性,在暗目标法的基础上,利用归一化植被指数NDVI实现森林样本自动选择;并融合NDVI构建了新的综合森林特征指数(Integrated Forest Z-Score,IFZ);以时间序列的IFZ分析森林动态信息,实现森林变化动态监测。以三峡大坝及周边区域森林为研究区,利用2001年至2012年每年生长季节(5月—10月)的Landsat TM影像检验本文算法。基于2002年、2006年和2010年三期7月—9月的Quick Bird影像的精度分析结果发现:研究区森林变化检测的总体精度可达96.53%,Kappa系数为0.9512。在添加NDVI指数后构建的IFZ提高了总体监测精度。其中,毁林类别的检测精度提高显著,漏检率和误检率分别为2.74%和3.64%;干扰后重建的森林类别的检测精度有一定提高,其漏检率和误检率分别为10.79%和10.51%。研究结果表明,改进暗目标法能提高森林样本的选样效率,添加NDVI的IFZ能提高森林动态变化的识别度。此外,本算法不仅能定性识别森林变化,而且能定量提供森林干扰发生时间和干扰强度。     

汶川地震灾后农田和森林植被恢复遥感监测

2008年汶川8.0级特大地震对当地的生态系统造成了极大的破坏,为了评估5年来灾区农田和森林植被的恢复情况,利用逐年机载高分辨率遥感影像,结合星载遥感数据和地面调查数据,开展了灾区农林植被恢复状况监测。在农田恢复监测方面,结合2008年地震发生后以及2013年5月中旬的机载高分辨率遥感数据,采用目视解译的方式对汶川地震中受损农田的恢复状况进行监测与评估,同时利用GVG(GPS、Video和GIS)农情采样系统的作物种植成数调查结果,分析了灾后作物种植结构的变化。结果表明,灾区1592 ha受损农田,5年后仅有约17.5%得到了恢复和耕种使用。就耕地利用强度而言,重灾区耕地利用率较高,作物种植结构没有发生重大变化。在森林恢复状况监测方面,对典型区(岷江干旱河谷区和盆周山地区的3个重点区域)采用目视解译方式识别出森林变化,并结合大区域尺度规一化植被指数(NDVI)时间序列变化分析,对整个灾区的森林损毁和恢复情况做出评价。监测结果显示,汶川县、什邡市和绵竹市的森林植被恢复情况总体较好,但是一些坡度较大的损毁区、次生灾害频发区的森林尚未恢复,大区域尺度的统计结果显示,地震重灾区的46381 ha重度损毁森林植被和177025 ha中度损毁森林植被区域,完全恢复的区域占13.52%和25.84%,部分恢复的区域都占到50%。在自然恢复较为困难的区域,如汶川县中部和东北部、都江堰市北部、彭州市北部、什邡市北部、绵竹市北部、安县北部及北川县南部等,需要加强人工干预。遥感监测方法既适用于震后的农田和森林恢复状况动态监测,也适用于其他自然灾害发生时对灾区农田和森林植被破坏状况进行应急监测,具有实际应用价值和良好的发展前景。     

Sentinel-2A数据支持下的雷州半岛植被类型识别

本文以雷州半岛为研究区,利用Sentinel-2A影像数据和真实植被样本数据,综合探讨了机器学习中随机森林与支持向量机的分类效果,并与传统的最大似然法进行比较。提取Sentinel-2A影像9个波段、7个植被指数、72个纹理特征,通过递归特征消除法挑选了10个特征组合,并将其应用于3种分类方法中,对其分类效果进行比较。结果表明:①有效使用多种特征变量是提高植被类型识别精度的关键,就不同特征对植被类型识别的重要性而言,光谱特征与纹理特征相当且大于植被指数,三者重要性相差不大;②随机森林分类效果最佳,不但能对特征进行有效选择,而且能保证植被类型提取精度,提高运行效率;③基于随机森林特征选择的递归特征消除法得到的特征组合不能对其他分类器性能进行优化,对随机森林模型本身的优化效果也有限。     

利用光学和SAR遥感数据的若尔盖湿地植被分类与变化监测

湿地植被在固碳过程中扮演重要角色。作为高寒湿地生态系统的典型代表，若尔盖湿地的植被分类与变化监测对于研究其碳汇功能具有重要意义。光学遥感和微波遥感在植被监测中各有其优缺点，因此本研究提出结合Sentinel-2光学数据和Sentinel-1合成孔径雷达SAR (Synthetic Aperture Radar)数据的若尔盖湿地植被分类与变化监测方法。基于动态时间归整算法DTW (Dynamic Time Warping)提取Sentinel-1 SAR数据的时间序列物候特征，结合Sentinel-2多光谱数据的光谱特征，以2020年实地获取的植被样本及使用样本迁移得到的2017年样本，通过随机森林算法分别对两个时期的若尔盖湿地植被进行分类并对其变化进行分析。研究表明：(1)结合Sentinel-1和Sentinel-2数据，充分发挥各自多时相、多光谱的优势对若尔盖湿地植被进行分类得到可靠的分类结果，总精度达到了97.43%,Kappa系数为0.96。(2)基于样本迁移原理，本研究通过将2020年实地采集的样本迁移至2017年，解决了历史时期实地样本不可得的问题，并针对SAR数据的特点提...     

利用多种传感器信息编制热带森林植被图的研究

本文介绍了利用卫星遥感编制西双版纳州热带森林植被图的研究方法。论述了以森林生态规律为导向,以多种传感器遥感信息为基础,通过计算机图像处理和森林植被分类判读,编制了热带森林植被图的技术过程。研究结果表明,利用多种传感器卫星遥感数据SPOT XS和TM,结合部份航空像片编制热带森林植被图是可行的。该图件的编制为西双版纳珍贵的热带森林植被的保护管理提供了重要的基础信息。     

基于随机森林分类方法和多源遥感数据的湿地植被精细分类

利用大丰市沿海滩涂湿地区域的高光谱影像和同时期的机载LIDAR数据,结合影像的光谱信息,采用随机森林算法(RF)对研究区进行湿地植被精细分类,并分析和评价分类模型参数设置对总体精度的影响,最后与SVM分类结果进行对比。结果表明:随机森林分类方法的总体精度为90.3%、卡帕(Kappa)系数为0.874;与传统的SVM分类方法相比,RF法均提高了4种湿地植被的生产者精度和使用者精度。通过分析RF分类模型参数设置对总体精度的影响,得出当生长树个数为30、生长树深度为30时,分类精度最高。     

利用MERIS数据植被指数分析福建省植被长势季节变化

监测植被长势动态变化可以提供生态系统状况有价值的信息,可以检测到人类或气候作用引起的变化。本研究利用2004—2005年间10期MERIS影像数据,以福建省为例,探讨MERIS数据在区域植被长势季节变化监测中的应用效果;分析了MERIS数据用于区域植被季节变化监测时的数据处理方法;比较了MERIS数据几种植被指数,提出了利用10和8波段组合改进MERISNDVI的建议;利用多时相合成的NDVI简单分析了2004年夏季—2005年夏季三个季节的植被长势状况。结果表明,MERIS植被指数的时空变化有效反映了气候变化对植被长势的影响。     

Interpretation of Synthetic Aperture Radar (SAR) imagery for geological appraisal: A comparative study in Anantapur district of Andhra Pradesh

The paper describes the details of a comparative study of geological interpretations carried out from Synthetic Aperture Radar (SAR) imagery, Landsat MSS (B & W) imagery and Aerial Photographs, covering 2100 sq km of area in Anantapur district of Andhra Pradesh. The area comprises Peninsular—Gneissic Complex and rocks of Dharwar and Cuddapah Super Groups beside the Quaternary alluvial deposits along the Penneru river and its tributaries. Geomorphologically the areas is represented by denudational, fluvial and structural landforms. The study indicates that the details of the geological and geomorphological maps prepared from SAR imagery and aerial photographs are comparable despite the smaller scale of SAR imagery while the same are not exhibited in Landsat imagery mainly due to its low resolution. Although broad lithological units are possible to be discriminated on SAR as well as aerial photographs, some of the finer rock types viz. gabbroic dykes could be discriminated from the delerite dykes in the SAR imagery due to their different surface roughness. Stereoscopic coverage and enhanced micro-relief of SAR imagery gives better geomorphological details in comparison to aerial photographs. A detailed study of lineaments has also been carried out which shows that in SAR imagery there is over-representation of short lineaments due to enhanced micro-relief and radarshadow effects across the look direction and under-representation of lineaments along the look direction. Landsat imagery is perhaps the best for demarcating lineaments of regional magnitude while aerial photographs are good for depicting shorter lineaments. However, certain lineaments seen in SAR imagery are often not continuously seen on aerial photographs.     

Utilisation of integrated remote sensing technique for coastal geomorphic and geologic data extraction—A case study for Coondapur,south Kanara district (Karnataka)

Coastal zone is associated with several geomorphic features of erosional and depositional nature, be sides the broad geologic information. The area around Coondapur of south Kanara district, Karnataka, possesses all the major characteristics of coastal zone and these are extractable through intergated remotely sensed data namely Landsat-1 MSS imagery, Salyut-7 KATE space photograph and aerial photographs. The visual interpretation is carried out with developing remote sensing keys to decipher major geomorphic-geologic information like: spit, double spit, beach deposit, alluvium, levee deposit, la|terite and other rock types. It is concluded that the major geomorphic-geologic characteristics as well as subdeltaic drainage, soil erosoin are obtained through space borne data. The aerial photographs provide the detailed geomorphic and geologic information.     

Vegetation recovery monitoring over the waste dump in Haizhou opencast coalmine area,China, during 1975–2000 using NDVI and VF index

Vegetation condition monitoring has been done from 1975 to 2000 in the waste dump of Haizhou opencast coalmine area, China, using remote sensing techniques with the objective of improving our understanding of the temporal and spatial variation of vegetation recovery in the mining dump. Four historical vegetation indexes (NDVI, VF, soil brightness and vegetation greenness) from two Landsat 2 MSS images and two Landsat 5 TM images are extracted and analyzed. For the purpose of comparison and analysis two improved techniques such as normalization grading of change slope and image segmentation were used in this study. Based on the results obtained through the above analysis two conclusions are derived: (1) vegetation recovery in the study area is in an improved condition, (2) two remote sensing based vegetation indexes such as VF and NDVI are the optimal parameters to monitor vegetation condition, which could be used as the indicators of land reclamation progress in the mining area.     

Geology of the area around Katta,sindhudurg district,Maharashtra. Based on aerospace data

Geological studies of the area around Katta, in the southern part of the Ratnagiri District of Maharashtra, were carried out with the help of visual remote sensing techniques using LANDSAT imageries on 1:250,000 scale and aerial photographs on 1:60,000 scale. The major stratigraphic units represented in the area under study are the Archean Complex, Kaladgi Supergroup, Deccan Trap, Laterite and Alluvium. The Kaladgis unconformably overlie the Archean metasediments and also at places exhibit faulted contacts with the latter. The major part of the area is covered by a thick evergreen vegetation. The interpretation followed by field work and laboratory work revealed the following:

1. The different lithologic units could be delineated on the aerial photographs.
2. Different lineaments marked on the imagery were found to be due either to faults or fracture zones. Some of the older faults appear to have been rejuvenated after the formation of the laterites.
3. Some of the lithologic horizons can be identified on the Landsat imagery by virtue of their spatial signatures.

These studies indicate that even in the area covered with thick vegetation, aerospace imagery in appropriate band and data scale can provide significant geological information.     

塔里木盆地周边地区泥石流灾害的遥感分析

本文以MSS图像和TM图像为基本信息源,从影响泥石流灾害形成的自然要素,如地质（岩性、构造）、地形地貌、植被、水文（河流、冰川、雪被）、地面物质组成以及泥石流沟的遥感判读入手,结合气象资料分析,对塔里木盆地周边地区泥石流灾害的类型、分布状况、孕育和诱发条件进行探讨,进一步对该区泥石流灾害发育程度进行区划,并对危险区进行预测。     

基于混合像元分解理论的路域植被等量水厚度遥感反演

为削弱混合像元对植被参数反演的影响,提出了基于混合像元分解理论反演路域植被等量水厚度的方法。利用PRO4SAIL模型正演获得的高光谱窄波段数据,模拟Landsat 8遥感影像宽波段植被冠层光谱数据,并进行等量水厚度的敏感植被指数的筛选;对覆盖研究区域的Landsat 8遥感影像进行线性混合像元分解,获取更加精确的植被冠层光谱反射率;同时,利用支持向量机构建等量水厚度估测模型,实现对路域植被等量水厚度的遥感反演。研究结果表明,利用混合像元分解后得到的植被冠层光谱参与模型反演得到的路域植被等量水厚度更加符合实际情况,为遥感影像反演植被参数提供了有效数据。     

3D Visualization for the Analysis of Forest Cover Change

Abstract

Visualization techniques have been developed to recreate natural landscapes, but little has been done to investigate their potential for illustrating land cover change using spatio‐temporal data. In this work, remote sensing, geographic information systems (GIS) and visualization techniques were applied to generate realistic computer visualizations depicting the dynamic nature of forested environments. High resolution digital imagery and aerial photography were classified using object‐oriented methods. The resulting classifications, along with preexisting land cover datasets, were used to drive the correct placement of vegetation in the visualized landscape, providing an accurate representation of reality at various points in time. 3D Nature's Visual Nature Studio was used to construct a variety of realistic images and animations depicting forest cover change in two distinct ecological settings. Visualizations from Yellowstone National Park focused on the dramatic impact of the 1988 fire upon the lodgepole pine forest. For a study area in Kansas, visualization techniques were used to explore the continuous human‐land interactions impacting the eastern deciduous forest and tallgrass prairie ecotone between 1941 and 2002. The resulting products demonstrate the flexibility and effectiveness of visualizations for representing spatio‐temporal patterns such as changing forest cover. These geographic visualizations allow users to communicate findings and explore new hypotheses in a clear, concise and effective manner.     

Study of geology and structure of perungulathur area in thiruvannamalai sambuvarayar district,tamil nadu,using remote sensing techniques

Remote sensing technique can play a vital role in geological, geomorphological and structural studies. Geology and structure of Perungulathur area in Thiruvannamalai Sambuvarayar district was studied by using Landsat imagery and aerial photographs with limited field checks. Charnockite, which forms the country rock of the area, and the interbedded pink granite and amphibolite exhibit typical tonal and textural characters on aerial photographs. The study has brought out a partly exposed structural basin which is represented by the folded structure of amphibolite and pink granite within the charnockitic country rock.     

一种利用多时相TM影像分析地表植被变化的新方法：——以敦煌地区绿洲植 …

变化分析是多时相遥感影像的主要应用领域。以敦煌绿洲为例,探讨一种应用多时相ＴＭ影像进行地表植被变化分析的新方法。结果证明,用不同时相的ＮＤＶＩ影像进行彩色合成可以直观地反映地表植被的变化,而利用色彩变换得到的各分量可以对变化特点进行定量分析。其中色度反映变化类型,饱和度反映变化强度,而亮度图像则反映地表植被多年来的总体长势。除了直观和定量的特性之外,该方法还可以用于其它类型的变化分析,具有可扩展性     

一种利用多时相TM影像分析地表植被变化的新方法--以敦煌地区绿洲植被变化分析为例

变化分析是多时相遥感影像的主要应用领域。以郭煌绿洲为例 ,探讨一种应用多时相TM影像进行地表植被变化分析的新方法。结果证明 ,用不同时相的NDVI影像进行彩色合成可以直观地反映地表植被的变化 ,而利用色彩变换得到的各分量可以对变化特点进行定量分析。其中色度反映变化类型 ,饱和度反映变化强度 ,而亮度图像则反映地表植被多年来的总体长势。除了直观和定量的特性之外 ,该方法还可以用于其它类型的变化分析 ,具有可扩展性