Proceedings of the Symposium on Global and Environmental Monitoring: Proceedings of the Symposium on Global and Environmental Monitoring

Bibliographic data

Multivolume work

Persistent identifier:: 856665355

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts ; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856665355

Language:: English

Document type:: Multivolume work

Volume

Persistent identifier:: 856669164

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Scope:: XIV, 912 Seiten

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856669164

Illustration:: Illustrationen, Diagramme, Karten

Signature of the source:: ZS 312(28,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [WP-3 FOREST INVENTORY APPLICATIONS]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: EVALUATING AIRBORNE LINEAR ARRAY TECHNOLOGY FOR OPERATIONAL FOREST INVENTORY APPLICATIONS IN BRITISH COLUMBIA. Paul G. Pilon

Document type:: Multivolume work

Structure type:: Chapter

386 The advantages of the newer generations of airborne linear array systems include: high spatial resolution, good radiometric resolution and sensitivity, flexible wavelength choice and the ability to use narrow wavelength bands. Some linear array systems also offer the ability to produce stereo images from which tree and stand height estimates should be possible. Another technological advance is the incorporation of high qualify inertial navigation data with airborne linear array data to permit more efficient and accurate geometric correction to cartographic coordinates. Linear array data and forest interpretation can then be input directly into a cartographically accurate forest inventory database on a geographic information system. In fact, with stereo capability it may be feasible to produce more accurate base maps using geo- referenced imagery and digital terrain models created from stereo linear array data. The following sections describe in more detail the unique characteristics, advantages and disadvantages of airborne linear array sensor systems. 2.1 Spatial Resolution The spatial resolution of airborne linear array data can be much higher then equivalent satellite-based systems and consequently airborne imagery can used as a viable alternative to medium-scale aerial photography. For forestry applications this means that stand-specific or even tree-specific information can be obtained from airborne imagery. The spatial resolution of these systems is determined by the field of view and the aircraft altitude. The MEIS II system, for example, can provide data at resolutions ranging from 0.25 to 10 meters. For forestry applications where information is often required at a variety of scales, from reconnaissance mapping to detailed forest measurements, imagery can be acquired at spatial resolutions appropriate for each specific application. In addition, this flexibility to choose spatial resolution makes airborne linear array imagery an ideal data source for multistage or multiphase sampling purposes. 2.2 Spectral Range For forestry applications where information on the vigour or condition of the vegetation is important there is often a need to use imagery acquired beyond the visible range in the middle-infrared portion of the electromagnetic spectrum. The MEIS sensor with a spectral range from 390 - 1100 nm can provide data in the important middle-infrared region. The FLI and CASI systems, on the other hand, were designed primarily for ocean applications and consequently are only able to provide data in the visible and near-infrared portions of the spectrum from 430 - 805 nm. There are plans to modify the CASI system to accommodate different sensor heads which would extend its spectral range farther into the infrared region (G.A. Borstad, personal communication) which would make these systems more suitable for forestry applications. 2.3 Spectral Resolution Spectral resolution (the number and width of spectral bands that can be selected) is controlled in one-dimensional linear array systems (e.g. MEIS) through interchangeable optical filters and in two-dimensional systems (e.g. FLI and CASI) through diffraction gratings. The MEIS sensor acquires imagery in up to eight spectral bands. Various sets of spectral filters are available for the MEIS system which have been optimized for specific applications, such as SPOT and TM simulations, stereo applications and forestry. Of particular interest for forestry have been the filter sets for vegetation stress studies (incorporating passbands of 3 nm width located on the chlorophyll red reflectance edge) which have provided more accurate forest insect and disease damage assessments (Kneppeck and Ahem, 1989; Epp and Reed, 1986). The vegetative red reflectance edge, which occurs in the 650-800nm spectral region, has received increased attention during the past several years as a potential indication of vegetative stress (McColl et aL, 1983). The ability to produce filters which isolate spectral bands as small as 3nm in this region provides the potential to detect very small spectral changes in the reflective red edge which could be important for early detection of vegetative stress resulting from insect or disease damage. The disadvantage of using optical filters to obtain spectral bands is the time required to determine the appropriate spectral range for each filter (usually accomplished by using data from non-imaging spectrometers) and the time and cost involved in manufacturing the appropriate filters. As imaging spectrometers, the FLI and CASI systems, have the ability to image 288 bands. For the FLI system each band can be as close as 1.3 nm and as narrow as 2.5 nm (Buxton, 1988). The CASI system can image 288 bands as narrow as 1.8 nm (Gower et al., 1987), when operating in its "spectral" mode. The spectral data from these bands can be used to examine and analyze the spectral signature of a target. The spectral signature can be important in helping to determine optimal spectral band width and positioning for use in acquiring high spatial resolution data. When acquiring data in the "spatial mode" eight spectral bands can be

Access restriction

Copyright

fullscreen: Proceedings of the Symposium on Global and Environmental Monitoring (Part 1)

Multivolume work

Volume

Chapter

Chapter

Table of contents

Cite and reuse

Volume

Chapter

Image

Image fragment

Citation links

Citation recommendation