Validation of a manual measurement method for deriving 3D canopy structure using the BPMS

Abstract

A fieldwork campaign was undertaken in East Anglia, UK (52 minutes 37.2 seconds N 0 minute 32.0 seconds E), during the winter/spring growing season of 1997. Manual structural measurements were made of individual plants from a variety of crops in order to allow detailed geometric representations of these plants to be constructed within the Botanical Plant Modelling System (BPMS) [1] [2] with the aim of exploring and validating the extraction of canopy structural information from a variety of remotely sensed data. Results are presented from simulations carried out using BPMS data of barley crops at a variety of stages of growth. Measured directional reflectance data are compared with BPMS simulations, and derived structural parameters (LAI, %age cover) compared with independent measurements made in the field. Results show that the derived reflectance values are generally in good agreement with those obtained by direct measurement, whilst the %age cover and LAI values are more variable. This may be due to the difficulty of characterising inherently variable parameters with limited manual measurements.