QuickBird影像目视解译法提取切沟形态参数的精度分析
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摘要
为了研究QuickBird影像提取切沟形态参数的精度,该文选取陕北黄土区吴起县合沟与绥德县桥沟小流域,分别利用同时相的三维激光扫描全站仪和QuickBird影像数据源提取切沟形态参数,分析QuickBird影像提取切沟形态参数的精度,探究误差产生原因。研究结果表明:与三维激光扫描全站仪相比,QuickBird影像目视解译合沟和桥沟小流域切沟面积、周长的平均相对误差都在5%左右;沟缘线边界偏差大于0.6 m(相当于QuickBird影像的一个像元值)的面积百分比的均值都能控制在4%以内;2个小流域中沟长的平均相对误差分别在2%和5%左右,沟长的平均绝对误差分别在0.5和0.75 m左右;目视解译面积、沟长的平均相对误差、最大相对误差、不同解译人员的最大误差与参数值之间都具有显著地负相关,即切沟越大,误差越小;沟缘线附近的植被类型影响目视解译精度,与灌草植被覆盖的小流域相比,草本覆盖的小流域中切沟参数的解译精度更高。总体上来看,QuickBird影像为小流域尺度上监测切沟发育提供了便捷、可靠地数据源。
High-resolution satellite images such as those from Ikonos and QuickBird are increasingly available and are considered a valuable tool for extracting the consequences of gully erosion, and QuickBird imagery has been used to map gully features. To evaluate the accuracy of extracting morphological parameters of bank gullies including area, perimeter, and length from QuickBird imagery by manual visual interpretation, and to analyze the causes of errors, 20 bank gullies were selected in Hegou catchment and Qiaogou catchment located in the Loess Plateau of northern Shaanxi province, respectively. 3D laser scanner was used to measure the topography of bank gullies within two weeks after the QuickBird images were taken. The interval among measurement points of 3D laser scanner was set as 0.15 m. 3D laser scanner had been increasingly used to measure the topography as it can provide a high accuracy, non-contacted, penetrating and rapid method that enables the rapid production of accurate, high-resolution digital elevation model(DEM). Based on Delaunay triangulated irregular networks(TIN), then DEM with the pixel size of 0.15 m × 0.15 m was created using the 3D Analyst extension of ArcGIS 9.3. On this basis, the values of morphological parameters extracted from DEM were taken as actual values and errors of morphological parameters of bank gullies extracted from QuickBird imagery were determined. The average absolute error, maximum absolute error, average relative error, maximum relative error, and maximum relative error among different interpretation persons were used to assess the accuracy of manual visual interpretation of QuickBird imagery. The results showed that maximum relative error of area and perimeter ranged from 4.1% to 22.2% and 1.4% to 22.2% in Hegou catchment, respectively, while maximum relative error ranged from 2.4% to 22.6% for area and 4.5% to 29.7% for perimeter in Qiaogou catchment, respectively. Although maximum relative error appeared to be large for some gullies, average relative error of area and perimeter were both about 5% in two study areas. In addition, by overlaying the two valley regions extracted from QuickBird imagery and DEM, the area that the distance offsets was larger than 0.6 m(QuickBird image one pixel value) remained below 4%. Average relative error of gully length in Hegou catchment and Qiaogou catchment were about 2% and 5%, respectively, with corresponding average of the average absolute error of 0.5 m and 0.75 m. Correlation analysis showed that average relative error, maximum relative error and maximum relative error among different interpretation persons were negatively correlated with the area and length of bank gully(P<0.05), which meant that the larger the area and length of bank gully were, the smaller the errors were. This suggested that choosing large gullies would reduce the errors when the morphological parameters were extracted manually from QuickBird imagery. The accuracy of manual visual interpretation was also influenced by the vegetation types near the gully boundary. Catchments which land was covered with native grassland had higher precision than those were covered with shrub and grass. Overall, QuickBird imagery can provide reliable data source for extracting morphological parameters of bank gullies. The results can provide the references for assessing gully erosion using QuickBird imagery at larger spatial scales rather than direct field measurements.
High-resolution satellite images such as those from Ikonos and QuickBird are increasingly available and are considered a valuable tool for extracting the consequences of gully erosion, and QuickBird imagery has been used to map gully features. To evaluate the accuracy of extracting morphological parameters of bank gullies including area, perimeter, and length from QuickBird imagery by manual visual interpretation, and to analyze the causes of errors, 20 bank gullies were selected in Hegou catchment and Qiaogou catchment located in the Loess Plateau of northern Shaanxi province, respectively. 3D laser scanner was used to measure the topography of bank gullies within two weeks after the QuickBird images were taken. The interval among measurement points of 3D laser scanner was set as 0.15 m. 3D laser scanner had been increasingly used to measure the topography as it can provide a high accuracy, non-contacted, penetrating and rapid method that enables the rapid production of accurate, high-resolution digital elevation model(DEM). Based on Delaunay triangulated irregular networks(TIN), then DEM with the pixel size of 0.15 m × 0.15 m was created using the 3D Analyst extension of ArcGIS 9.3. On this basis, the values of morphological parameters extracted from DEM were taken as actual values and errors of morphological parameters of bank gullies extracted from QuickBird imagery were determined. The average absolute error, maximum absolute error, average relative error, maximum relative error, and maximum relative error among different interpretation persons were used to assess the accuracy of manual visual interpretation of QuickBird imagery. The results showed that maximum relative error of area and perimeter ranged from 4.1% to 22.2% and 1.4% to 22.2% in Hegou catchment, respectively, while maximum relative error ranged from 2.4% to 22.6% for area and 4.5% to 29.7% for perimeter in Qiaogou catchment, respectively. Although maximum relative error appeared to be large for some gullies, average relative error of area and perimeter were both about 5% in two study areas. In addition, by overlaying the two valley regions extracted from QuickBird imagery and DEM, the area that the distance offsets was larger than 0.6 m(QuickBird image one pixel value) remained below 4%. Average relative error of gully length in Hegou catchment and Qiaogou catchment were about 2% and 5%, respectively, with corresponding average of the average absolute error of 0.5 m and 0.75 m. Correlation analysis showed that average relative error, maximum relative error and maximum relative error among different interpretation persons were negatively correlated with the area and length of bank gully(P<0.05), which meant that the larger the area and length of bank gully were, the smaller the errors were. This suggested that choosing large gullies would reduce the errors when the morphological parameters were extracted manually from QuickBird imagery. The accuracy of manual visual interpretation was also influenced by the vegetation types near the gully boundary. Catchments which land was covered with native grassland had higher precision than those were covered with shrub and grass. Overall, QuickBird imagery can provide reliable data source for extracting morphological parameters of bank gullies. The results can provide the references for assessing gully erosion using QuickBird imagery at larger spatial scales rather than direct field measurements.
引文
[1]景可.黄土高原沟谷侵蚀研究[J].地理科学,1986,6(4):340-347.Jing Ke.A study on gully erosion on the Loess Plateau[J].Scientia Geographic Sinica,1986,6(4):340-347.(in Chinese with English abstract)
[2]伍永秋,刘宝元.切沟、切沟侵蚀与预报[J].应用基础与工程科学学报,2000,8(2):134-142.Wu Yongqiu,Liu Baoyuan.Gully,Gully erosion and predicition[J].Journal of Basic Science and Engineering,2000,8(2):134-142.(in Chinese with English abstract)
[3]Poesen J,Nachtergale J,Vertstraeten G,et al.Gully erosion and environmental change:Importance and research needs[J].Catena,2003,50(2/3/4):91-133.
[4]Li Y,Poesen J,Yang J C,et al.Evaluating gully erosion using 137Cs and 210Pb/137Cs ratio in a reservoir catchment[J].Soil&Tillage Research,2003,69(1/2):107-115.
[5]Wu Yongqiu,Cheng Hong.Monitoring of gully erosion on the Loess Plateau of China using a global positioning system[J].Catena,2005,50(2/3):154-166.
[6]Crouch R J.The relationship of gully sidewall shape to sediment production[J].Australian Journal of Soil Research,1987,25(4):531-539.
[7]Vandekerckhove L,Poesen J,Govers G.Medium-term gully headcut retreat rates in Southeast Spain determined from aerial photographs and ground measurements[J].Catena,2003,50(2/3/4):329-352.
[8]Wu Yongqiu,Zheng Qiuhong,Zhang Yongguang,et al.Development of gullies and sediment production in black soil region of northeastern China[J].Geomorphology,2008,101(4):683-691.
[9]Perroy R L,Bookhagen B,Asner G P,et al.Comparison of gully erosion estimates using airborne and ground-based LiDAR on Santa Cruz Island California[J].Geomorphology,2010,118(3/4):288-300.
[10]秦伟,朱清科,赵磊磊,等.基于RS和GIS的黄土丘陵沟壑区浅沟侵蚀地形特征研究[J].农业工程学报,2010,26(6):58-64.Qin Wei,Zhu Qingke,Zhao Leiei,et al.Topographic characteristics of ephemeral gully erosion in loess hilly and gully region based on RS and GIS[J].Transactions of the Chinese Society of Agricultural Engineering(Transaction of the CSAE),2010,26(6):58-64.(in Chinese with English abstract)
[11]Cheng Hong,Zou Xueyong,Wu Yongqiu,et al.Morphology parameters of ephemeral gully in characteristics hillslopes on the Loss Plateau of China[J].Soil&Tillage Research,2007,94(1):4-14.
[12]Jackson T J,Ritchie J C,White J,et al.Airborne laser profile data for measuring ephemeral gully erosion[J].Photogrammetric Engineering and Remote Sensing,1988,54(8):1181-1185.
[13]Ritchie J C,Grissinger E H,Murphey J B,et al.Measuring channel and gully cross-sections with an airborne laser altimeter[J].Hydrological Processes,1994,8(4):237-244.
[14]Romanescu G,Cotiuga V,Asandulesei A,et al.Use of the 3-D scanner in mapping and monitoring the dynamic degradation of soils:Case study of the Cucuteni-Baiceni Gully on the Moldavian Plateau(Romania)[J].Hydrology and Earth System Sciences,2012,16(3):953-966.
[15]Hancock G R,Evans K G.Channel head location and characteristics using digital elevation models[J].Earth Surface Processes and Landforms,2006,31(7):809-824.
[16]Evans M,Lindsay J.High resolution quantification of gully erosion in upland peatlands at the landscape scale[J].Earth Surface Process Land forms,2010,35(8):876-886.
[17]张姣,郑粉莉,温磊磊,等.利用三维激光扫描技术动态监测沟蚀发育过程的方法研究[J].水土保持通报,2011,31(6):89-94.Zhang Jiao,Zheng Fenli,Wen Leilei,et al.Methodolody of dynamic monitoring gully erosion process using 3D laser scanning technology[J].Bulletin of Soil and Water Conservation,2011,31(6):89-94.(in Chinese with English abstract)
[18]张鹏,郑粉莉,王彬,等.高精度GPS,三维激光扫描和测针板三种测量技术监测沟蚀过程的对比研究[J].水土保持通报,2008,28(5):11-15.Zhang Peng,Zheng Fenli,Wang Bin,et al.Comparative study of monitoring gully erosion morphology change process by using high precision GPS,Leica HDS 3000laser scanner and needle board method[J].Bulletin of Soil and Water Conservation,2008,28(5):11-15.(in Chinese with English abstract)
[19]马玉凤,严平,时云莹,等.三维激光扫描全站仪在土壤侵蚀监测中的应用——以青海省共和盆地威连滩冲沟监测为例[J].水土保持通报,2010,30(2):177-179.Ma Yufeng,Yan Ping,Shi Yunying,et al.Application of laser 3D scanner in soil erosion research:Taking gully erosion monitoring in Weiliantan,Gonghe Basin,Qinghai Province as an example[J].Bulletin of Soil and Water Conservation,2010,30(2):177-179.(in Chinese with English abstract)
[20]张大林,刘希林.应用三维激光扫描监测崩岗侵蚀地貌变化——以广东五华县莲塘岗崩岗为例[J].热带地理,2014,34(2):133-140.Zhang Dalin,Liu Xilin.Application of 3D laser scanning to monitoring the landform changes of collapsing hill and gully.A case study of Liantanggang collapsing hill and gully in the Wuhua county of Guangdong[J].Tropical Geography,2014,34(2):133-140.(in Chinese with English abstract)
[21]Knight J,Spencer J,Brooks A,et al.Large-area,high-resolution remote sensing based mapping of alluvial gully erosion in Australia's tropical rivers[C].Proceedings of the 5th Australian Stream Management Conference.Australian Rivers:Making a Difference.Charles Sturt University,Thurgoona,New South Wales,2007:199-204.
[22]马玉凤,严平,王耿锐,等.青海共和盆地威连滩冲沟侵蚀遥感监测的初步结果[J].水土保持研究,2009,16(2):1-5.Ma Yufeng,Yan Ping,Wang Gengrui,et al.Preliminary results of gully erosion by remote sensing monitoring in Weiliantan,Gonghe Basin,Qinghai Province[J].Research of Soil and Water Conservation,2009,16(2):1-5.(in Chinese with English abstract)
[23]Tebebu T Y,Abiy A Z,Zegeye A D,et al.Surface and subsurface flow effect on permanent gully formation and upland erosion near Lake Tana in the northern highlands of Ethiopia[J].Hydrology and Earth System Sciences,2010,14(11):2207-2217.
[24]Shruthi R B V,Kerle N,Jetten V.Object-based gully feature extraction using high spatial resolution imagery[J].Geomorphology,2011,134(3/4):260-268.
[25]朱岩,张岩,朱清科,等.半干旱黄土区沟间天然草地植被空间分异特征[J].生态学杂志,2011,30(6):1063-1069.Zhu Yan,Zhang Yan,Zhu Qingke,et al.Spatial distribution patterns of vegetations on natural grassland in Loess Plateau interfluve[J].Chinese Journal of Ecology,2011,30(6):1063-1069.(in Chinese with English abstract)
[26]游智敏,伍永秋,刘宝元.利用GPS进行切沟侵蚀监测研究[J].水土保持学报,2004,18(5):91-94.You Zhimin,Wu Yongqiu,Liu Baoyuan.Study of monitoring gully erosion using GPS[J].Journal of Soil and Water Conservation,2004,18(5):91-94(in Chinese with English abstract)
[27]Frankl A,Poesen J,Scholiers N,et al.Factors controlling the morphology and volume(V)—length(L)of permanent gullies in the northern Ethiopian Highlands[J].Earth Surface Processes and Landforms,2013,38(14):1672-1684.
[2]伍永秋,刘宝元.切沟、切沟侵蚀与预报[J].应用基础与工程科学学报,2000,8(2):134-142.Wu Yongqiu,Liu Baoyuan.Gully,Gully erosion and predicition[J].Journal of Basic Science and Engineering,2000,8(2):134-142.(in Chinese with English abstract)
[3]Poesen J,Nachtergale J,Vertstraeten G,et al.Gully erosion and environmental change:Importance and research needs[J].Catena,2003,50(2/3/4):91-133.
[4]Li Y,Poesen J,Yang J C,et al.Evaluating gully erosion using 137Cs and 210Pb/137Cs ratio in a reservoir catchment[J].Soil&Tillage Research,2003,69(1/2):107-115.
[5]Wu Yongqiu,Cheng Hong.Monitoring of gully erosion on the Loess Plateau of China using a global positioning system[J].Catena,2005,50(2/3):154-166.
[6]Crouch R J.The relationship of gully sidewall shape to sediment production[J].Australian Journal of Soil Research,1987,25(4):531-539.
[7]Vandekerckhove L,Poesen J,Govers G.Medium-term gully headcut retreat rates in Southeast Spain determined from aerial photographs and ground measurements[J].Catena,2003,50(2/3/4):329-352.
[8]Wu Yongqiu,Zheng Qiuhong,Zhang Yongguang,et al.Development of gullies and sediment production in black soil region of northeastern China[J].Geomorphology,2008,101(4):683-691.
[9]Perroy R L,Bookhagen B,Asner G P,et al.Comparison of gully erosion estimates using airborne and ground-based LiDAR on Santa Cruz Island California[J].Geomorphology,2010,118(3/4):288-300.
[10]秦伟,朱清科,赵磊磊,等.基于RS和GIS的黄土丘陵沟壑区浅沟侵蚀地形特征研究[J].农业工程学报,2010,26(6):58-64.Qin Wei,Zhu Qingke,Zhao Leiei,et al.Topographic characteristics of ephemeral gully erosion in loess hilly and gully region based on RS and GIS[J].Transactions of the Chinese Society of Agricultural Engineering(Transaction of the CSAE),2010,26(6):58-64.(in Chinese with English abstract)
[11]Cheng Hong,Zou Xueyong,Wu Yongqiu,et al.Morphology parameters of ephemeral gully in characteristics hillslopes on the Loss Plateau of China[J].Soil&Tillage Research,2007,94(1):4-14.
[12]Jackson T J,Ritchie J C,White J,et al.Airborne laser profile data for measuring ephemeral gully erosion[J].Photogrammetric Engineering and Remote Sensing,1988,54(8):1181-1185.
[13]Ritchie J C,Grissinger E H,Murphey J B,et al.Measuring channel and gully cross-sections with an airborne laser altimeter[J].Hydrological Processes,1994,8(4):237-244.
[14]Romanescu G,Cotiuga V,Asandulesei A,et al.Use of the 3-D scanner in mapping and monitoring the dynamic degradation of soils:Case study of the Cucuteni-Baiceni Gully on the Moldavian Plateau(Romania)[J].Hydrology and Earth System Sciences,2012,16(3):953-966.
[15]Hancock G R,Evans K G.Channel head location and characteristics using digital elevation models[J].Earth Surface Processes and Landforms,2006,31(7):809-824.
[16]Evans M,Lindsay J.High resolution quantification of gully erosion in upland peatlands at the landscape scale[J].Earth Surface Process Land forms,2010,35(8):876-886.
[17]张姣,郑粉莉,温磊磊,等.利用三维激光扫描技术动态监测沟蚀发育过程的方法研究[J].水土保持通报,2011,31(6):89-94.Zhang Jiao,Zheng Fenli,Wen Leilei,et al.Methodolody of dynamic monitoring gully erosion process using 3D laser scanning technology[J].Bulletin of Soil and Water Conservation,2011,31(6):89-94.(in Chinese with English abstract)
[18]张鹏,郑粉莉,王彬,等.高精度GPS,三维激光扫描和测针板三种测量技术监测沟蚀过程的对比研究[J].水土保持通报,2008,28(5):11-15.Zhang Peng,Zheng Fenli,Wang Bin,et al.Comparative study of monitoring gully erosion morphology change process by using high precision GPS,Leica HDS 3000laser scanner and needle board method[J].Bulletin of Soil and Water Conservation,2008,28(5):11-15.(in Chinese with English abstract)
[19]马玉凤,严平,时云莹,等.三维激光扫描全站仪在土壤侵蚀监测中的应用——以青海省共和盆地威连滩冲沟监测为例[J].水土保持通报,2010,30(2):177-179.Ma Yufeng,Yan Ping,Shi Yunying,et al.Application of laser 3D scanner in soil erosion research:Taking gully erosion monitoring in Weiliantan,Gonghe Basin,Qinghai Province as an example[J].Bulletin of Soil and Water Conservation,2010,30(2):177-179.(in Chinese with English abstract)
[20]张大林,刘希林.应用三维激光扫描监测崩岗侵蚀地貌变化——以广东五华县莲塘岗崩岗为例[J].热带地理,2014,34(2):133-140.Zhang Dalin,Liu Xilin.Application of 3D laser scanning to monitoring the landform changes of collapsing hill and gully.A case study of Liantanggang collapsing hill and gully in the Wuhua county of Guangdong[J].Tropical Geography,2014,34(2):133-140.(in Chinese with English abstract)
[21]Knight J,Spencer J,Brooks A,et al.Large-area,high-resolution remote sensing based mapping of alluvial gully erosion in Australia's tropical rivers[C].Proceedings of the 5th Australian Stream Management Conference.Australian Rivers:Making a Difference.Charles Sturt University,Thurgoona,New South Wales,2007:199-204.
[22]马玉凤,严平,王耿锐,等.青海共和盆地威连滩冲沟侵蚀遥感监测的初步结果[J].水土保持研究,2009,16(2):1-5.Ma Yufeng,Yan Ping,Wang Gengrui,et al.Preliminary results of gully erosion by remote sensing monitoring in Weiliantan,Gonghe Basin,Qinghai Province[J].Research of Soil and Water Conservation,2009,16(2):1-5.(in Chinese with English abstract)
[23]Tebebu T Y,Abiy A Z,Zegeye A D,et al.Surface and subsurface flow effect on permanent gully formation and upland erosion near Lake Tana in the northern highlands of Ethiopia[J].Hydrology and Earth System Sciences,2010,14(11):2207-2217.
[24]Shruthi R B V,Kerle N,Jetten V.Object-based gully feature extraction using high spatial resolution imagery[J].Geomorphology,2011,134(3/4):260-268.
[25]朱岩,张岩,朱清科,等.半干旱黄土区沟间天然草地植被空间分异特征[J].生态学杂志,2011,30(6):1063-1069.Zhu Yan,Zhang Yan,Zhu Qingke,et al.Spatial distribution patterns of vegetations on natural grassland in Loess Plateau interfluve[J].Chinese Journal of Ecology,2011,30(6):1063-1069.(in Chinese with English abstract)
[26]游智敏,伍永秋,刘宝元.利用GPS进行切沟侵蚀监测研究[J].水土保持学报,2004,18(5):91-94.You Zhimin,Wu Yongqiu,Liu Baoyuan.Study of monitoring gully erosion using GPS[J].Journal of Soil and Water Conservation,2004,18(5):91-94(in Chinese with English abstract)
[27]Frankl A,Poesen J,Scholiers N,et al.Factors controlling the morphology and volume(V)—length(L)of permanent gullies in the northern Ethiopian Highlands[J].Earth Surface Processes and Landforms,2013,38(14):1672-1684.