Tree Crown Mapping in Managed Woodlands (Parklands) of Semi-Arid West Africa Using WorldView-2 Imagery and Geographic Object Based Image Analysis

Sensors

Martin Karlson²  Heather Reese¹ 

[1] Section of Forest Remote Sensing, Department of Forest Resource Management, Swedish University of Agricultural Sciences, Umeå 901 83, Sweden; E-Mail:;Centre for Climate Science and Policy Research, Department of Thematic Studies/Environmental Change, Linköping University, Linköping 58183, Sweden; E-Mail:

关键词: remote sensing;    high spatial resolution;    WorldView-2;    tree crown mapping;    tree crown delineation;    geographic object based image analysis;    woodland;    agroforestry;    parkland;    Burkina Faso;   

DOI  :  10.3390/s141222643

来源: mdpi

【 摘 要 】

Detailed information on tree cover structure is critical for research and monitoring programs targeting African woodlands, including agroforestry parklands. High spatial resolution satellite imagery represents a potentially effective alternative to field-based surveys, but requires the development of accurate methods to automate information extraction. This study presents a method for tree crown mapping based on Geographic Object Based Image Analysis (GEOBIA) that use spectral and geometric information to detect and delineate individual tree crowns and crown clusters. The method was implemented on a WorldView-2 image acquired over the parklands of Saponé, Burkina Faso, and rigorously evaluated against field reference data. The overall detection rate was 85.4% for individual tree crowns and crown clusters, with lower accuracies in areas with high tree density and dense understory vegetation. The overall delineation error (expressed as the difference between area of delineated object and crown area measured in the field) was 45.6% for individual tree crowns and 61.5% for crown clusters. Delineation accuracies were higher for medium (35–100 m²) and large (≥100 m²) trees compared to small (<35 m²) trees. The results indicate potential of GEOBIA and WorldView-2 imagery for tree crown mapping in parkland landscapes and similar woodland areas.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.