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在总结分析山东省典型区域填海造地现状的基础上,对数据包络分析法在填海造地有效性综合评价领域进行了尝试应用,包括构建填海造地影响评价指标体系,以及以山东烟台、威海、潍坊、青岛和日照5个典型区域为例进行填海造地的有效性评价。 相似文献
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针对基岩、人工、砂质和淤泥质海岸四种海岸类型,采用数据挖掘算法中的C4.5决策树算法对Landsat 8OLI多光谱影像数据进行分析。首先得出4种海岸类型中所包含的海水、陆地、植被、养殖区、淤泥、沙滩六种地物的识别规则;然后利用不同海岸类型所包含的地物类型差异,分别提出了基岩、人工建筑、人工养殖、沙滩、淤泥五种海岸类型的自动识别规则。实例验证结果表明,对于地物特征明显的人工海岸和基岩海岸,我们提出的海岸类型自动识别方法的精度可达到100%,而对于光谱相近的淤泥质海岸和人工养殖海岸其识别精度较低,大于80%。 相似文献
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Since the atmospheric correction is a necessary preprocessing step of remote sensing image before detecting green tide, the introduced error directly affects the detection precision. Therefore, the detection method of green tide is presented from Landsat TM/ETM plus image which needs not the atmospheric correction. In order to achieve an automatic detection of green tide, a linear relationship(y =0.723 x+0.504) between detection threshold y and subtraction x(x=λ_(nir)–λ_(red)) is found from the comparing Landsat TM/ETM plus image with the field surveys.Using this relationship, green tide patches can be detected automatically from Landsat TM/ETM plus image.Considering there is brightness difference between different regions in an image, the image will be divided into a plurality of windows(sub-images) with a same size firstly, and then each window will be detected using an adaptive detection threshold determined according to the discovered linear relationship. It is found that big errors will appear in some windows, such as those covered by clouds seriously. To solve this problem, the moving step k of windows is proposed to be less than the window width n. Using this mechanism, most pixels will be detected[n/k]×[n/k] times except the boundary pixels, then every pixel will be assigned the final class(green tide or sea water) according to majority rule voting strategy. It can be seen from the experiments, the proposed detection method using multi-windows and their adaptive thresholds can detect green tide from Landsat TM/ETM plus image automatically. Meanwhile, it avoids the reliance on the accurate atmospheric correction. 相似文献
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大西洋牙鲆胚胎发育的形态观察 总被引:9,自引:0,他引:9
为了掌握大西洋牙鲆早期发育的规律,2005年2月在实验室利用显微镜和显微数码摄像显示系统观察测量拍摄大西洋牙鲆受精卵胚胎发育和初孵仔鱼的形态特征,描述并记录其发育过程和时间。大西洋牙鲆的卵为球形游离的浮性卵,卵径平均977μm,单油球,偶见2或3油球,油球径180μm。在水温19~20.8℃时孵化,大约受精后50 min胚盘形成,5 h30 min进入囊胚期,8 h后进入原肠胚期,21 h左右进入胚体器官分化期,40 h后尾部游离,心跳开始,胚体搐动,51~52 h孵出。实验表明,大西洋牙鲆受精卵的孵化进度与水温相关。孵化时间(Ht)与水温(t/℃)关系方程为Ht=3 154.8t-1.333 6(R2=0.925 4)。 相似文献
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