VOLUME 63, NUMBER 3
PHOTOGRAMMETRIC ENGINEERING & REMOTE
SENSING
JOURNAL OF THE AMERICAN SOCIETY FOR PHOTOGRAMMETRY
AND REMOTE SENSING
Cover Image
This image shows the site of the tragic ValuJet Flight 592 crash in the Florida
Everglades on 11 May 1996. The image was acquired on 15 August 1996, as part
of a U.S. Geological Survey ecosystem study, using the Digital Multispectral
Video (DMSV) system developed by SpecTerra Ltd., Perth, Australia, and the
U.S. Army Topographic Engineering Center. The DMSV is a four-camera, multispectral
imaging system that allows specific spectral bands to be selected using filtered
fore-optics. The false color composite comprises three 25-nm-wide spectral
bands centered at 770 nm (red), 650 nm (green), and 550 nm (blue). The image
array is 740 by 578 pixels with a resolution of about 0.3 m, and covers an
area of 5.2 hectares in this scene. Evident features include the impact zone
where open water appears black along with the major airboat trails that resulted
from recovery operations. Sawgrass (Cladium jamaicense) and other
types of aquatic vegetation are shown in hues of red, pink, and orange, with
numerous airboat scars that are evident as striations throughout the image.
Algal periphyton is shown in white, and dead vegetation caused by spilled jet
fuel adjacent to the impact zone is shown in bluish green. The DMSV was mounted
in a Piper Aztec twin-engine aircraft operated by Pro-Flight Aviation of Macon,
Ga., and is one of several sensors being used to develop land characteristics
data sets in support of USGS's South Florida Ecosystem Program.
Concurrent in situ measurements of Chlorophyll a, pheophytin a,
total suspended solids, total dissolved solids, and turbidity were compared
with SPOT data for three reservoirs in north Texas.
The regressed relationship between in situ suspended sediment concentration
level and its digital number from scanned aerial photographs was tested and
was most accurate at 10 m among the four spatial resolutions studied.
Utilizing digitized aerial photographs and topographic maps in a GIS, changes
in area, shift of centroid, and rotation of marsh islands were quantified.
The results from the radar observations were found to be consistent with theoretical
microwave scattering models that predict variations in backscatter as a function
of vegetation structure, soil moisture, surface roughness, and the presence
or absence of standing water.
Comparison of three sites before, during, and after the hurricane passage
corraborated the atypical phenology of the impacted forested wetland and directly
related the cause to the hurricane passage.
Digitized infrared photographs can be used to map crop growth within fields
for precision farming applications, but multi-year studies are recommended
to determine effects of climate on crop variability and mapping precision.
Announcements
ASPRS 1997 Annual Meeting
General Information
ASPRS Workshops
Advance Registration Form
Housing Form
ASPRS/ACSM/RT/Auto-Carto 13
Technical Sessions
1997 Geospatial Information Age- ACSM/ASPRS/RTI Annual Meeting & AutoCarto
13
Meeting: Softcopy Photogrammetry Applications: Using the Tools
Call for Papers: GIS Special PE&RS Issue
Call for Papers: 12th Intl. Conference & Workshops on Applied Geologic Remote
Sensing
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Softcopy
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Meeting Report: Eco-Informa `96
In Memoriam — Richard E. Dahlberg, Gary Nies
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