Gessner, Ursula and Machwitz, Miriam and Conrad, Christopher and Dech, Stefan (2013) Estimating the fractional cover of growth forms and bare surface in savannas. A multi-resolution approach based on regression tree ensembles. Remote Sensing of Environment, 129, pp. 90-102. Elsevier. doi: 10.1016/j.rse.2012.10.026.
![]() |
PDF
2MB |
Abstract
Evaluations of existing land cover maps have revealed that high landscape heterogeneity and small patch sizes are a major reason for misclassification. These problems globally occur in biomes of mixed vegetation structure and are particularly relevant for African savannas. This paper presents a multi-resolution approach to derive fractional cover of vegetation growth forms at sub-pixel level, aiming at an improved mapping of land cover in the African grassland, savanna and shrubland biome. Fractional cover is delineated for woody growth forms (trees and shrubs), herbaceous growth forms, and bare surface. The approach incorporates very high resolution (QuickBird/IKONOS, 0.6–1 m), high resolution (Landsat TM/ETM+, 30 m), and medium resolution data (MODIS, 250 m). While QuickBird/IKONOS data are classified into discrete classes, at Landsat and MODIS resolutions, sub-pixel cover is delineated using non-parametric ensemble regression trees from the random forest family. The propagation of errors in the hierarchical multi-resolution approach is assessed with Monte Carlos simulations. The multi-resolution approach allows the adequate description of the heterogeneous vegetation structure in selected study regions of Southern Africa. The RMSE of the delineated fractional cover values range between 3.1% and 8.2% when compared with higher resolution data and between 4.4% and 9.9% when compared with field surveys. Errors at the Landsat resolution show minor influence on the accuracy of the MODIS results. Regarding the inter-resolution error propagation, for 90% of the Monte Carlo simulations, errors at the Landsat resolution resulted in RMSEs for MODIS increased by less than 4% (woody vegetation), 3.5% (herbaceous vegetation) and 2% (bare surface).
Item URL in elib: | https://elib.dlr.de/79611/ | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Document Type: | Article | |||||||||||||||
Title: | Estimating the fractional cover of growth forms and bare surface in savannas. A multi-resolution approach based on regression tree ensembles | |||||||||||||||
Authors: |
| |||||||||||||||
Date: | 2013 | |||||||||||||||
Journal or Publication Title: | Remote Sensing of Environment | |||||||||||||||
Refereed publication: | Yes | |||||||||||||||
Open Access: | Yes | |||||||||||||||
Gold Open Access: | No | |||||||||||||||
In SCOPUS: | Yes | |||||||||||||||
In ISI Web of Science: | Yes | |||||||||||||||
Volume: | 129 | |||||||||||||||
DOI: | 10.1016/j.rse.2012.10.026 | |||||||||||||||
Page Range: | pp. 90-102 | |||||||||||||||
Publisher: | Elsevier | |||||||||||||||
Status: | Published | |||||||||||||||
Keywords: | Sub-pixel fractional cover; Savanna; Grassland and shrubland biome; Africa; Vegetation structure; Land cover; Multi-resolution analysis | |||||||||||||||
HGF - Research field: | Aeronautics, Space and Transport | |||||||||||||||
HGF - Program: | Space | |||||||||||||||
HGF - Program Themes: | Earth Observation | |||||||||||||||
DLR - Research area: | Raumfahrt | |||||||||||||||
DLR - Program: | R EO - Earth Observation | |||||||||||||||
DLR - Research theme (Project): | R - Vorhaben Fernerkundung der Landoberfläche (old) | |||||||||||||||
Location: | Oberpfaffenhofen | |||||||||||||||
Institutes and Institutions: | German Remote Sensing Data Center > Land Surface | |||||||||||||||
Deposited By: | Gessner, Ursula | |||||||||||||||
Deposited On: | 14 Feb 2013 10:19 | |||||||||||||||
Last Modified: | 31 Jul 2019 19:38 |
Repository Staff Only: item control page