Improved Classification of Urban Trees Using a Widespread Multi-Temporal Aerial Image Dataset

• Main Authors: Daniel S. W. Katz, Stuart A. Batterman, Shannon J. Brines
• Format: Article
• Language: English
• Published: MDPI AG 2020-08-01
• Series: Remote Sensing
• Subjects: LiDAR; remote sensing; tree classification; GEOBIA; urban forests
• Online Access: https://www.mdpi.com/2072-4292/12/15/2475

Urban tree identification is often limited by the accessibility of remote sensing imagery but has not yet been attempted with the multi-temporal commercial aerial photography that is now widely available. In this study, trees in Detroit, Michigan, USA are identified using eight high resolution red, green, and blue (RGB) aerial images from a commercial vendor and publicly available LiDAR data. Classifications based on these data were compared with classifications based on World View 2 satellite imagery, which is commonly used for this task but also more expensive. An object-based classification approach was used whereby tree canopies were segmented using LiDAR, and a street tree database was used for generating training and testing datasets. Overall accuracy using multi-temporal aerial images and LiDAR was 70%, which was higher than the accuracy achieved with World View 2 imagery and LiDAR (63%). When all data were used, classification accuracy increased to 74%. Taxa identified with high accuracy included <i>Acer platanoides</i> and <i>Gleditsia</i>, and taxa that were identified with good accuracy included <i>Acer</i>, <i>Platanus, Quercus,</i> and <i>Tilia</i>. Our results show that this large catalogue of multi-temporal aerial images can be leveraged for urban tree identification. While classification accuracy rates vary between taxa, the approach demonstrated can have practical value for socially or ecologically important taxa.