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

A fieldwork campaign was undertaken in East Anglia, UK (52° 37.2´ N 0° 32.0´ E), during the winter/spring growing 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) with the aim of exploring and validating 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, percentage 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 percentage cover and LAI values are more variable. This may be due to the difficulty of characterising inherently variable parameters with limited manual measurements