Sfap

Small-format aerial photography is based on lightweight cameras with 35- or 70-mm film format as well as equivalent digital cameras and other electronic imaging devices. For the most part, these are "popular" cameras designed for hand-held or tripod use by amateur and professional photographers. Such cameras lack the geometric fidelity and exceptional spatial resolution of aerial mapping cameras. However, the case for SFAP depends on cost and accessibility.

• Low cost: SFAP cameras are relatively inexpensive, few $100 to several $1000, compared with large-format aerial cameras at several $100,000. The cost of SFAP platforms ranges from only a few $100 for kites to tens of $1000 for larger and more sophisticated aircraft. These costs put SFAP within the financial means for many individuals and organizations that could otherwise not afford to acquire conventional aerial photography suitable for their needs.

FIGURE1-14 Overview of the forest blowdown zone on the southern flank of the Tatra Mountains at Tatranska Polianka, Slovakia. Three years after the windstorm, pink-purple common fireweed (Epilobium angustifolium) bloomed profusely in the blowdown zone across the middle portion of this scene. Kite aerial photo by SWA and JSA, July 2007.

FIGURE1-14 Overview of the forest blowdown zone on the southern flank of the Tatra Mountains at Tatranska Polianka, Slovakia. Three years after the windstorm, pink-purple common fireweed (Epilobium angustifolium) bloomed profusely in the blowdown zone across the middle portion of this scene. Kite aerial photo by SWA and JSA, July 2007.

• Logistics: low-height, large-scale imagery is feasible with various manned or unmanned platforms. SFAP may be acquired in situations that would be impractical, risky, or impossible for operating larger aircraft.

• SFAP has high portability, rapid field setup and use, and limited need for highly trained personnel, all of which makes this means for aerial photography logistically possible for many applications.

Low-cost availability of cameras and lifting platforms is a combination that renders SFAP desirable for many people and organizations (Malin and Light, 2007). SFAP is self-made remote sensing—system design, technical implementation, and image analysis may be in the hands of a single person, granting utmost flexibility and specialization.

Manned platforms include single-engine airplanes, helicopters, ultralight aircraft, hot-air balloons, large blimps, and sailplanes. These are necessarily more expensive and require specialized pilot training in contrast to most unmanned platforms, such as balloons, blimps, kites, model airplanes, and drones. Within the field of aerial photography, much innovation is taking place nowadays with all types of platforms and imaging equipment.

As a specialty within remote sensing, SFAP fills a niche of observational scale, resolution, and height between the ground and conventional aerial photography or satellite imagery—a range that is particularly valuable for detailed site investigations of environmental conditions at the Earth's surface. SFAP is employed in various applications ranging from geoscience to wildlife habitat, archaeology, crime-scene investigation, and real-estate development.

Within the past decade, commercial satellite imagery of the Earth has achieved 1-m, panchromatic, spatial resolution, and resolution less than half a meter may come soon (Tatem et al., 2008). Such resolution may be possible in principle; however, satellite systems must look through atmospheric haze 100s of kilometers thick, which degrades image quality. Operating close to the surface, SFAP provides sub-decimeter, multispectral, spatial resolution with usually insignificant atmospheric effects.

As an example, consider mapping vegetation at Kushiro wetland on Hokkaido, northern Japan. Aerial photography is hampered at Kushiro by persistent sea fog derived from cold offshore currents during the summer growing season when vegetation is active. Miyamoto et al. (2004) utilized two tethered helium balloons to acquire vertical airphotos of a study site in Akanuma marsh (Fig. 1-15). A standard Nikon F-801 camera was utilized with a 28 mm lens, skylight filter, and color negative film. Combined weight of the radio-controlled camera rig and balloon tether was ~ 3.5 kg. In total, 66 pictures were taken from 120 m height over the study site.

FIGURE 1-15 Ground views of balloons and camera rig used for aerial photography at Kushiro wetland, Japan. Each balloon is 2.4 m in diameter with a helium capacity of 7 m3. Taken from Miyamoto et al. (2004, fig. 3); used with permission of the authors.

Original photographs were scanned at 600 dots per inch (dpi), which yielded spatial resolution of 15 cm/ pixel. Twenty-three images were selected for mosaicking and georeferencing based on ground control points surveyed with GPS. The mosaic was inspected visually; vegetation types were identified with the help of ground observations, and polygons were digitized on-screen to delineate each vegetation class. On this basis, a detailed map of vegetation was prepared (Fig. 1-16). These results were considered superior to an earlier attempt using high-cost Ikonos satellite imagery, which was obscured by typical fog. The balloon system allowed the investigators to take quick advantage of brief fog-free conditions to acquire useful imagery. This example demonstrates the spatial, temporal, and cost advantages of SFAP to succeed in a situation where other remote-sensing techniques had not proven capable.

Digital Camera and Digital Photography

Digital Camera and Digital Photography

Compared to film cameras, digital cameras are easy to use, fun and extremely versatile. Every day there’s more features being designed. Whether you have the cheapest model or a high end model, digital cameras can do an endless number of things. Let’s look at how to get the most out of your digital camera.

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