DOI: 10.1016/j.jag.2013.05.003
Scopus记录号: 2-s2.0-84897572445
论文题名: Combining airborne laser scanning data and optical satellite data for classification of alpine vegetation
作者: Rees H ; , Nyström M ; , Nordkvist K ; , Olsson H
刊名: International Journal of Applied Earth Observation and Geoinformation
ISSN: 15698432
出版年: 2014
卷: 27, 期: PARTA 起始页码: 81
结束页码: 90
语种: 英语
英文关键词: Alpine
; Elevation derivatives
; Laser data metrics
; Shrub
; SPOT
; Willow
Scopus关键词: alpine environment
; canopy
; climate change
; image classification
; laser method
; optical method
; satellite data
; shrub
; SPOT
; subalpine environment
; vegetation cover
; Abisko
; Norrbotten
; Sweden
; Betula pubescens subsp. tortuosa
; Salix
; Salix petrophila
英文摘要: Climate change and outdated vegetation maps are among the reasons for renewed interest in mapping sensitive alpine and subalpine vegetation. Satellite data combined with elevation derivatives have been shown to be useful for mapping alpine vegetation, however, there is room for improvement. The inclusion of airborne laser scanning data metrics has not been widely investigated for alpine vegetation. This study has combined SPOT 5 satellite data, elevation derivatives, and laser data metrics for a 25 km × 31 km study area in Abisko, Sweden. Nine detailed vegetation classes defined by height, density and species composition in addition to snow/ice, water, and bare rock were classified using a supervised Random Forest classifier. Several of the classes consisted of shrub and grass species with a maximum height of 0.4 m or less. Laser data metrics were calculated from the nDSM based on a 10 m × 10 m grid, and after variable selection, the metrics used in the classification were the 95th and 99th height percentiles, a vertical canopy density metric, the mean and standard deviation of height, a vegetation ratio based on the raw laser data point cloud with a variable height threshold (from 0.1 to 1.0 m with 0.1 m intervals), and standard deviation of these vegetation ratios. The satellite data used in classification was all SPOT bands plus NDVI and NDII, while the elevation derivatives consisted of elevation, slope and the Saga Wetness Index. Overall accuracy when using the combination of laser data metrics, elevation derivatives and SPOT 5 data increased by 6% as compared to classification of SPOT and elevation derivatives only, and increased by 14.2% compared to SPOT 5 data alone. The classes which benefitted most from inclusion of laser data metrics were mountain birch and alpine willow. The producer's accuracy for willow increased from 18% (SPOT alone) to 41% (SPOT + elevation derivatives) and then to 55% (SPOT + elevation derivatives + laser data) when laser data were included, with the 95th height percentile and Saga Wetness Index contributing most to willow's improved classification. Addition of laser data metrics did not increase the classification accuracy of spectrally similar dry heath (<0.3 m height) and mesic heath (0.3-1.0 m height), which may have been a result of laser data penetration of sparse shrub canopy or laser data processing choices. The final results show that laser data metrics combined with satellite data and elevation derivatives contributed overall to a better classification of alpine and subalpine vegetation. © 2013 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/79756
Appears in Collections: 气候变化事实与影响
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作者单位: Section of Forest Remote Sensing, Department of Forest Resource Management, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden
Recommended Citation:
Rees H,, Nyström M,, Nordkvist K,et al. Combining airborne laser scanning data and optical satellite data for classification of alpine vegetation[J]. International Journal of Applied Earth Observation and Geoinformation,2014-01-01,27(PARTA)