This study aims to assess and to evaluate band ratios, brovey and HSV (Hue-Saturation-Value) techniques for discrimination and mapping the basement rock units exposed at Wadi Bulghah area, Saudi Arabia using multispec...This study aims to assess and to evaluate band ratios, brovey and HSV (Hue-Saturation-Value) techniques for discrimination and mapping the basement rock units exposed at Wadi Bulghah area, Saudi Arabia using multispectral Landsat ETM+ and SPOT-5 panchromatic data.?FieldSpec instrument is utilized to collect the spectral data of diorite, marble, gossan and volcanics, the main rock units exposed at the study area. Spectral profile of diorite exhibits very distinguished absorption features around 2.20 μm and 2.35 μm wavelength regions. These absorption features lead to lowering the band ratio values within the band-7 wavelength region. Diorite intrusions appear to have grey and dark grey image signatures on 7/3 and 7/2 band ratio images respectively. On the false color composite ratio image (7/3:R;7/2:G and 5/2:B), diorite, marble, gossan and volcanics have very dark brown, dark blue, white and yellowish brown image signatures respectively. Image fusion between previously mentioned FCC ratio image and high spatial resolution (5 meters) SPOT-5 panchromatic image is carried out by using brovey and HSV transformation methods. Visual and statistical assessment methods prove that HSV fused image yields best image interpretability results rather than brovey image. It improves the spatial resolution of the original FCC ratios image with acceptable spectral preservation.展开更多
高时空分辨率叶面积指数(leaf area index,LAI)数据能反映作物的长势动态变化,为作物长势评估和产量预测提供有效的生长指标依据。该文综合利用混合像元线性分解与数据同化算法,以高空间分辨率SPOT-5数据反演的LAI修正高时间分辨率HJ-CC...高时空分辨率叶面积指数(leaf area index,LAI)数据能反映作物的长势动态变化,为作物长势评估和产量预测提供有效的生长指标依据。该文综合利用混合像元线性分解与数据同化算法,以高空间分辨率SPOT-5数据反演的LAI修正高时间分辨率HJ-CCD数据反演的LAI序列,生成了覆盖冬小麦主要生育期的高空间分辨率LAI序列,并结合SPOT-5反演的LAI和实测LAI值分析了像元纯度、高空间分辨率遥感数据同化景数对融合效果的影响。结果表明,采用数据融合方法生成的LAI与检验LAI具有较高的一致性,但像元纯度对融合效果影响较大;基于2景SPOT-5影像能够提高LAI序列估测精度,且优于基于1景SPOT-5影像的融合效果。该研究结果可为冬小麦生长监测提供技术支撑。展开更多
矿区土地覆盖变化信息的高精度提取,是区域资源环境保护和地质灾害防治领域的关键问题。以SPOT-5高分辨率卫星影像为数据源,以分类后比较法为变化信息提取方法,利用分类性能良好的支持向量机(SVM)为分类算法,分别设置不同SVM核函数及参...矿区土地覆盖变化信息的高精度提取,是区域资源环境保护和地质灾害防治领域的关键问题。以SPOT-5高分辨率卫星影像为数据源,以分类后比较法为变化信息提取方法,利用分类性能良好的支持向量机(SVM)为分类算法,分别设置不同SVM核函数及参数对实验样区进行分类,并评价分析不同核函数及参数对分类效果的影响。实验发现在4种核函数中高斯核函数分类精度最高,为87.1%;Sigmoid和多项式核函数分类精度适中,线性核函数分类精度最低,为78.7%。因此,利用高斯核函数分别对3个时相的大屯矿区影像进行分类,提取出变化信息空间分布并定量统计分析其变化特征。结果表明:矿区植被覆盖面积在近十年内持续减少18.539 km 2,塌陷面积共扩大4.379 km 2,而矿区厂矿增加、煤矿开采规模扩大、采煤塌陷区面积扩大以及耕地占用面积增大等人为因素,是威胁大屯矿区生态环境的主要因素。展开更多
The objective of this study is to evaluate the capability of satellite imagery for the estimation of basal area in Northern Zagros Forests. The data of the high resolution geometric (HRG) sensor of SPOT-5 satellite da...The objective of this study is to evaluate the capability of satellite imagery for the estimation of basal area in Northern Zagros Forests. The data of the high resolution geometric (HRG) sensor of SPOT-5 satellite dated in July 2005 were used. Investigation of the quality of Satellite images shows that these images have no radiometric distortion. Overlaying of geocoded images with the digital topographic maps indicated that the images have high geometric precision. A number of 319 circular plots (0.1 ha) were established using systematic random method in the study area. All trees having diameter at breast height (DBH) (i.e. 1.3 m above ground) greater than 5 cm were callipered in each plot. Basal area in each plot was determined using field data. Main bands, artificial bands such as vegetation indices and principle component analysis (PCA) were studied. Digital numbers related to each plot were extracted from original and artificial bands. All plots were ordinated by major geographic aspects and the best fitted regression models were determined for both the study area without consideration of aspects and with consideration of major geographic aspects by multiple regression analysis (step wise regression). The results from regression analysis indicated that the square root of basal area without consideration of aspects has a high correlation with band B1 (r = –0.60). The consideration of aspects resulted in correlation of different indices with square root of basal area such that in northern forests, band B1 had higher correlation coefficient(r = –0.67) among other indices. In Eastern forests, the same band showed correlation of basal area with different correlation coefficient (r = –0.65). In southern and western forests, the square root of basal area had higher correlation (r = –0.68) with RVI. The use of the square root of basal area as a dependent variable in multivariate linear regression improved the results. The assessment of model validity indicated that the proposed models are properly valid.展开更多
文摘This study aims to assess and to evaluate band ratios, brovey and HSV (Hue-Saturation-Value) techniques for discrimination and mapping the basement rock units exposed at Wadi Bulghah area, Saudi Arabia using multispectral Landsat ETM+ and SPOT-5 panchromatic data.?FieldSpec instrument is utilized to collect the spectral data of diorite, marble, gossan and volcanics, the main rock units exposed at the study area. Spectral profile of diorite exhibits very distinguished absorption features around 2.20 μm and 2.35 μm wavelength regions. These absorption features lead to lowering the band ratio values within the band-7 wavelength region. Diorite intrusions appear to have grey and dark grey image signatures on 7/3 and 7/2 band ratio images respectively. On the false color composite ratio image (7/3:R;7/2:G and 5/2:B), diorite, marble, gossan and volcanics have very dark brown, dark blue, white and yellowish brown image signatures respectively. Image fusion between previously mentioned FCC ratio image and high spatial resolution (5 meters) SPOT-5 panchromatic image is carried out by using brovey and HSV transformation methods. Visual and statistical assessment methods prove that HSV fused image yields best image interpretability results rather than brovey image. It improves the spatial resolution of the original FCC ratios image with acceptable spectral preservation.
文摘高时空分辨率叶面积指数(leaf area index,LAI)数据能反映作物的长势动态变化,为作物长势评估和产量预测提供有效的生长指标依据。该文综合利用混合像元线性分解与数据同化算法,以高空间分辨率SPOT-5数据反演的LAI修正高时间分辨率HJ-CCD数据反演的LAI序列,生成了覆盖冬小麦主要生育期的高空间分辨率LAI序列,并结合SPOT-5反演的LAI和实测LAI值分析了像元纯度、高空间分辨率遥感数据同化景数对融合效果的影响。结果表明,采用数据融合方法生成的LAI与检验LAI具有较高的一致性,但像元纯度对融合效果影响较大;基于2景SPOT-5影像能够提高LAI序列估测精度,且优于基于1景SPOT-5影像的融合效果。该研究结果可为冬小麦生长监测提供技术支撑。
文摘矿区土地覆盖变化信息的高精度提取,是区域资源环境保护和地质灾害防治领域的关键问题。以SPOT-5高分辨率卫星影像为数据源,以分类后比较法为变化信息提取方法,利用分类性能良好的支持向量机(SVM)为分类算法,分别设置不同SVM核函数及参数对实验样区进行分类,并评价分析不同核函数及参数对分类效果的影响。实验发现在4种核函数中高斯核函数分类精度最高,为87.1%;Sigmoid和多项式核函数分类精度适中,线性核函数分类精度最低,为78.7%。因此,利用高斯核函数分别对3个时相的大屯矿区影像进行分类,提取出变化信息空间分布并定量统计分析其变化特征。结果表明:矿区植被覆盖面积在近十年内持续减少18.539 km 2,塌陷面积共扩大4.379 km 2,而矿区厂矿增加、煤矿开采规模扩大、采煤塌陷区面积扩大以及耕地占用面积增大等人为因素,是威胁大屯矿区生态环境的主要因素。
文摘The objective of this study is to evaluate the capability of satellite imagery for the estimation of basal area in Northern Zagros Forests. The data of the high resolution geometric (HRG) sensor of SPOT-5 satellite dated in July 2005 were used. Investigation of the quality of Satellite images shows that these images have no radiometric distortion. Overlaying of geocoded images with the digital topographic maps indicated that the images have high geometric precision. A number of 319 circular plots (0.1 ha) were established using systematic random method in the study area. All trees having diameter at breast height (DBH) (i.e. 1.3 m above ground) greater than 5 cm were callipered in each plot. Basal area in each plot was determined using field data. Main bands, artificial bands such as vegetation indices and principle component analysis (PCA) were studied. Digital numbers related to each plot were extracted from original and artificial bands. All plots were ordinated by major geographic aspects and the best fitted regression models were determined for both the study area without consideration of aspects and with consideration of major geographic aspects by multiple regression analysis (step wise regression). The results from regression analysis indicated that the square root of basal area without consideration of aspects has a high correlation with band B1 (r = –0.60). The consideration of aspects resulted in correlation of different indices with square root of basal area such that in northern forests, band B1 had higher correlation coefficient(r = –0.67) among other indices. In Eastern forests, the same band showed correlation of basal area with different correlation coefficient (r = –0.65). In southern and western forests, the square root of basal area had higher correlation (r = –0.68) with RVI. The use of the square root of basal area as a dependent variable in multivariate linear regression improved the results. The assessment of model validity indicated that the proposed models are properly valid.
