Mua lại các hình ảnh Chúng tôi có thể mong đợi bản dịch của những khả năng này của xe không gian và cảm biến từ xa liên quan đến một loạt các chương trình ứng dụng. - E. M. Risley, 1967 Lĩnh vực, trên không, và hình ảnh vệ tinh Hình ảnh kỹ thuật số từ xa cảm ứng của rừng có thể được mua từ trên hiện trường, không khí, và các nền tảng vệ tinh. Hình ảnh từ mỗi nền tảng có thể cung cấp một tập hợp dữ liệu để hỗ trợ phân tích và mô hình hóa rừng,. | Acquisition of Imagery We can look forward to the translation of these capabilities of space vehicles and associated remote sensors into a variety of applications programs. E. M. Risley 1967 FIELD AERIAL AND SATELLITE IMAGERY Digital remote sensing images of forests can be acquired from field-based airborne and satellite platforms. Imagery from each platform can provide a data set with which to support forest analysis and modeling and those data sets may be complementary. For example field-based remote sensing observations might be comprised of a variety of plot or site photographs or images Chen et al. 1991 and nonimaging spectroscopy measurements Miller et al. 1976 which together with airborne or satellite data can be used to extend the detailed analysis of a small site to larger and larger study areas. Many types of ground platforms . handheld tripod ladder mast tower tramway or cable car boom cherry picker have been used in remote sensing of forest canopy spectral reflectance Blackburn and Milton 1997 . The variety of free-flying airborne platforms that have been employed in collecting remote sensing observations is nothing short of astonishing at various times airships Inoue et al. 2000 balloons paragliders remotely piloted aircraft ultralight aircraft and all manner of fixed-wing light aircraft have all been used with varying degrees of success in remote sensing. While not all of these have operational potential it is a virtual certainty that in supporting sustainable forest management activities in a forest region a variety of imagery and data from field-based airborne and satellite platforms will be required. Photographic systems have been designed for plot or site hemispherical photography to characterize canopy conditions Figure . A hemispherical photograph is a permanent record and a valuable source of canopy gap position size density and distribution information Frazer et al. 1997 . Measurements on the photograph can lead to estimates of selected
