面向对象的湖北省土地覆被变化遥感快速监测

为了快速监测湖北省土地覆被变化,以HJ-CCD、TM以及ETM影像为数据源,探索出了集成面向对象技术与"3S"技术的中尺度土地覆被变化遥感流程和方法。该方法首先基于HJ-CCD影像和面向对象技术进行2010年湖北省土地覆被信息的提取,并用野外采样点对结果进行验证。在保证高精度的情况下利用向量相似性函数对湖北省2000－2005年以及2005－2010年进行变化检测,从而获得2个变化时期影像的变化区域,然后利用面向对象技术中的最邻近分类器对变化区进行自动化分类。最后分别将2期的变化结果与未变化结果融合后获得湖北省2000年、2005年和2010年的土地覆被图,在GIS中处理后建成县、市、省3级行政级别的湖北省土地覆被变化本底数据库。试验表明分类结果的总体精度为93.24%,Kappa系数为0.914;2000－2005年与2005－2010年变化检测的总体精度分别为90.88%和90.75%。同时研究发现景观破碎的地区应用面向对象技术有一定的局限性。     

A method for mapping the distribution of willow at a catchment scale using bi-seasonal SPOT5 imagery

This study showed that seasonal imagery acquired at specific stages of phenology can be used to improve the mapping accuracy of invasive willow at a catchment scale. SPOT5 XI (10 m) satellite imagery was acquired for early autumn and winter to represent the phenological stages of leaf cover and leaf fall respectively. Four classification regimes were evaluated using single‐ and bi‐seasonal composite imagery to determine the most accurate method. Significant spectral noise was found in willow populations, especially in the winter image, due to the effects of undergrowth exposure, shadowing, topography and boundary‐mixed pixels. Two noise reduction techniques were applied to the bi‐seasonal composite image to improve the classification results. The noise‐reduced bi‐seasonal composite image was classified using the spectral angle mapper (SAM) algorithm before importation into a geographical information system. Aerial photography was used to reduce the errors of commission associated with misclassification of pastures. The class accuracy achieved for willow using the method described in this study was 77.5% (Kappa =0.87). The high cost of eradicating willow means that managers must establish priorities for control; this technique can provide a powerful tool for prioritizing control programmes and for monitoring results at a catchment scale.     

竹林禅韵——论竹的环境意象之一

作为一种具体环境构成的植物元素，竹与其它元素一起可形成一种充满寂、空、静、虚的空无境界，具有佛家禅韵。本文通过对竹与佛教的渊源、若干竹环境实例的分析，加以论证。     

ER Mapper软件进行几何精校正的原理和方法

几何精校正是利用地面控制点(GCP)对遥感图像进行几何校正.用ER Mapper软件进行几何精校正,主要包括参数设置、控制点输入和几何精校正.影响几何精校正的因素,主要表现在GCP的数量、分布和本身的定位精度,校正方法不同,影响也不同.     

无人机多光谱影像辐射一致性自动校正

针对一个架次内无人机影像由于光照度变化、拍摄角度等原因引起的相同地物点在不同影像上的辐射信息不一致的问题,验证了利用SIFT(scale invariant feature transform)算法匹配同名点,然后利用同名点灰度值的相关关系建立校正模型,再用该校正模型校正整幅影像的辐射一致性校正方法。对比评价了基于直方图匹配的色彩一致性校正方法、原始色彩空间辐射一致性校正、针对三波段影像的HSV(hue,saturation,value)色彩空间亮度一致性校正以及双边滤波去噪的效果。试验结果表明:基于直方图匹配的色彩一致性校正能在视觉上达到很好的效果,但是会造成校正后影像的灰度级严重缺失;基于同名点灰度值相关关系的校正模型能够很好地恢复待校正影像与基准影像的辐射一致性;HSV色彩空间亮度一致性校正能够在色彩上和辐射信息上与基准影像均达到很好的一致性,但只适用于三波段影像;双边滤波在去除噪声的同时,能够保持甚至提高校正后影像与基准影像的辐射一致性。     

Analysis of Land use and Land Cover Changes in the Coastal Area of Bangladesh using Landsat Imagery

Coastal land use across the globe has experienced remarkable rapid change over the recent decades because of extraordinary anthropogenic pressure and climate variability and change. Therefore, quantitative information about coastal land use change is imperative for effective management and planning resources for sustainable development. We analysed the quantitative land use and land cover changes during 1989–2000–2010 periods in three important agroecological zones of the most vulnerable coastal region of Bangladesh using Landsat images (Thematic Mapper/Enhanced Thematic Mapper Plus). In the Ganges Tidal Floodplain, the area under shrimp cultivation greatly increased at the rate of 2·05% per annum. The majority of the shrimp area gained from conversion of single cropland. In the Meghna Estuarine Floodplain, decreased mudflat and water bodies were observed, which was predominantly converted into cropland. In Chittagong Coastal Plain, salt pan–shrimp area increased with the expense of single and/or double cropland. In all the study areas, settlement area considerably increased over time. The dynamics of land use change have been attributed to low and unstable food production in the coastal region. The approach adopted in study and the results obtained from the study would likely be useful for policy making and identifying direction for future studies on the coastal land use in Bangladesh. Copyright © 2015 John Wiley & Sons, Ltd.     

试用“气韵生动”分析中国古典园林造园艺术

从“气韵生动”这一绘画美学理论的特殊视角来分析中国古典园林的造园艺术，阐述了“气”和“韵”在中国古典园林的具体体现。说明“气韵生动”是中国古典园林的一个重要特征，从这一角度来研究中国古典园林会给我们带来新的启发。     

黑河流域ASTER与MODIS融合生成高分辨率地表温度的验证

融合多源遥感数据生成高时空分辨率数据具有重要的应用价值。为了解决高空间分辨率数据重访周期长及云雨天气带来的数据短缺问题,该文基于增强自适应的遥感图像时空融合方法(enhanced spatial and temporal adaptive reflectance fusion model,ESTARFM),使用多时相MODIS数据提供地物时间变化信息,结合ASTER影像提供的空间细节信息,选择多波段数据(可见光近红外数据和地表温度数据)共同作为输入变量融合生成高时空地表温度。融合结果分别与地表红外辐射计观测温度和ASTER温度产品进行了验证。验证结果表明:基于ESTARFM方法降尺度地表温度影像清晰,融合结果与地表红外辐射计观测温度呈显著的线性正相关关系,相关系数均高于为0.71,预测得到的地表温度与真实测得的数据的平均绝对偏差均低于2.00 K,均方根误差均低于2.60 K。与ASTER地表温度产品的验证中,整体验证结果的R2均在0.95以上。此外,ESTARFM方法在各个地类中的融合效果较好,均表现出非植被区域的相关性高于植被和水体,尤其在2012年8月27日非植被的R2达到0.91。     

Comparison of QuickBird Satellite Imagery and Airborne Imagery for Mapping Grain Sorghum Yield Patterns

Timely and accurate information on crop conditions obtained during the growing season is of vital importance for crop management. High spatial resolution satellite imagery has the potential for mapping crop growth variability and identifying problem areas within fields. The objectives of this study were to use QuickBird satellite imagery for mapping plant growth and yield patterns within grain sorghum fields as compared with airborne multispectral image data. A QuickBird 2.8-m four-band image covering a cropping area in south Texas, USA was acquired in the 2003 growing season. Airborne three-band imagery with submeter resolution was also collected from two grain sorghum fields within the satellite scene. Yield monitor data collected from the two fields were resampled to match the resolutions of the airborne imagery and the satellite imagery. The airborne imagery was related to yield at original submeter, 2.8 and 8.4 m resolutions and the QuickBird imagery was related to yield at 2.8 and 8.4 m resolutions. The extracted QuickBird images for the two fields were then classified into multiple zones using unsupervised classification and mean yields among the zones were compared. Results showed that grain yield was significantly related to both types of image data and that the QuickBird imagery had similar correlations with grain yield as compared with the airborne imagery at the 2.8 and 8.4 m resolutions. Moreover, the unsupervised classification maps effectively differentiated grain production levels among the zones. These results indicate that high spatial resolution satellite imagery can be a useful data source for determining plant growth and yield patterns for within-field crop management.     

山区林地多季相TM影像综合分类研究

为了提高陆地卫星TM数据在山区林地的分类精度,利用4个季节的帽儿山TM数据进行植被分类,并辅助以物候特征和地面GIS专题信息 采用由简单到复杂的信息提取过程,先利用基于光谱知识的林地提取模型提取林地边界,再用有监分类方法分别进行林地和非林地内部类型信息的提取,生成多季相综合分类图 分类精度比单时相提高了19 6%