Fixed-base large-scale photographs for forest sampling

Spencer, R. D.

doi:10.1016/0031-8663(79)90010-3

Cited by 8 publications

(5 citation statements)

References 3 publications

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“…Remote sensing has a long history in the study of ecosystems. The first studies using remote sensing were based on airborne (infrared) imagery that allowed for a birds-eye view of ecosystems (Estes 1966;Bowden and Brooner 1970), as well as for the stereographic analysis of vegetation properties (Spencer 1979). Repeating aerial image analysis over time revealed novel insights into how ecosystems change (Mast and others 1997), insights that were impossible to generate with field data alone.…”

Section: A Brief History Of Remote Sensing For Studying Ecosystem Dyn...mentioning

confidence: 99%

Seeing the System from Above: The Use and Potential of Remote Sensing for Studying Ecosystem Dynamics

Senf

2022

Ecosystems

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Remote sensing techniques are increasingly used for studying ecosystem dynamics, delivering spatially explicit information on the properties of Earth over large spatial and multi-decadal temporal extents. Yet, there is still a gap between the more technology-driven development of novel remote sensing techniques and their applications for studying ecosystem dynamics. Here, I review the existing literature to explore how addressing these gaps might enable recent methods to overcome longstanding challenges in ecological research. First, I trace the emergence of remote sensing as a major tool for understanding ecosystem dynamics. Second, I examine recent developments in the field of remote sensing that are of particular importance for studying ecosystem dynamics. Third, I consider opportunities and challenges for emerging open data and software policies and suggest that remote sensing is at its most powerful when it is theoretically motivated and rigorously ground-truthed. I close with an outlook on four exciting new research frontiers that will define remote sensing ecology in the upcoming decade.

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Section: A Brief History Of Remote Sensing For Studying Ecosystem Dyn...mentioning

confidence: 99%

Seeing the System from Above: The Use and Potential of Remote Sensing for Studying Ecosystem Dynamics

Senf

2022

Ecosystems

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“…Progressive accounts of developments in large-scale photographic equipment and methods have been published over the past 35 years by various authors, principally from Canada as summarised by Spencer and Hall ( 1988) and more recently in Australia (Spencer 1979, Biggs et a/. 1989, Biggs 1990, Biggs and Spencer 1990, Spencer 1992.…”

Section: Large-scale Photo-mensurationmentioning

confidence: 99%

“…The first method uses a twin-camera fixed-base system and relies on the known air-base and precise synchronisation of the cameras during exposure to calculate photographic scale, with the fixed orientation of the cameras being used to control tilts (Lyons 1966, 1967, Spencer 1979, Spencer and Hall 1988. The second method uses a single-camera and timedinterval photography, with a laser altimeter and tilt recorder to determine scale and tilts respectively Lowe 1978, Nielsen et a/.…”

Section: Large-scale Photo-mensurationmentioning

confidence: 99%

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Small format aerial photography: methods and achievements in Australian forestry

Spencer

1998

Australian Forestry

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Since the mid 1960s Australian forestry has benefited from small format aerial photography (SFAP) for testing new films, scales and photographic conditions; for supplementing major aerial surveys by monitoring changes on small-scale images and using this information to intensify maps, such as plantings and roads in new plantations; for achieving special effects, such as shadowless large-scale coverage to detect understorey details (e.g. disease symptoms) and for double sampling at large scales in conjunction with Global Positioning System (GPS) navigation and Geographic Information Systems (GIS) analysis to obtain quantitative data for a flexible, responsive information system. Results from early photographic and mapping trials were quickly incorporated into operational procedures which are now widely applied. Likewise, a major program utilising the special effects of large scale shadow less SFAP for disease detection has been operational for many years. However, double sampling for volume inventories has only recently been applied, in spite of trials in the 1960s. The paper outlines requirements in each of these categories and uses examples from operational programs to illustrate their application.

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“…Others encountered image blur (caused by helicopter vibration) and an unstable base (when twin cameras were mounted parallel to the flight path). Numerous designs have been modified (Befort, 1988;Forest Research Institute, 1989;Lyons, 1966;Spencer, 1979;Williams, 1978) but, for the most part, few have become operational because of geometric instability or expense.…”

Section: Introductionmentioning

confidence: 99%

Application and Accuracy of Two Fixed Base Camera Systems

Warner¹,

Reutebuch

1999

The Photogrammetric Record

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This paper discusses the application of two fixed base non-metric camera systems. The first is a helicopter supported 5 m boom carrying two 70 mm Hasselblad cameras, fired simultaneously. The 1Ϻ850 scale stereomodels, each covering about 40ϫ45 m, were used to measure individual tree characteristics, such as crown closure and size. The second system is a portable camera platform designed for microtopography, which used sequential Minolta 35 mm photography (1Ϻ80 scale) for generating DEMs and computing volume of soil erosion. In both cases, an analytical plotter was used to collect measurements without ground control. With the helicopter boom system, distances and heights were measured to within 5 per cent of true dimensions. With the portable platform system, volume estimates were within 1 per cent of field measurement values. Particular attention is given to the orientation and scaling of stereopairs. Because the air base is used to scale the model, errors in scale due to non-parallel lines of sight are avoided. Advantages and disadvantages of both systems are discussed.

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Fixed-base large-scale photographs for forest sampling

Cited by 8 publications

References 3 publications

Seeing the System from Above: The Use and Potential of Remote Sensing for Studying Ecosystem Dynamics

Seeing the System from Above: The Use and Potential of Remote Sensing for Studying Ecosystem Dynamics

Small format aerial photography: methods and achievements in Australian forestry

Application and Accuracy of Two Fixed Base Camera Systems

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