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Investigation:

LC-07 (Melack / Novo / Forsberg)

LBA Dataset ID:

LC07_Amazon_Videography_1999

Originator(s):

1. Melack, John M.
2. Novo, Evlyn Marcia Leao de Moraes
3. Hess, Laura
4. Mertes, Leal, (deceased)
5. Slaymaker, Dana Munro
6. Gastil-Buhl, Mary (Gastil)
      7. Valeriano, Dalton De Morisson
8. Krug, Thelma
9. Hayward, Chris
10. Holt, J.
11. Steffen, C.
12. Holmes, C.

Point(s) of Contact:

Gastil-Buhl, Mary (Gastil) (mary@icess.ucsb.edu)
Affonso, Adriana (affonso@ltid.inpe.br)

Dataset Abstract:

Four Validation Overflights for Amazon Mosaics (VOAM) aerial video surveys have been carried out in the Brazilian Amazon to provide ground verification for mapping of wetland cover with the Global Rain Forest Mapping (GRFM) Project JERS-1 (Japanese Earth Remote Sensing Satellite) mosaics of the Amazon basin. Surveys in 1995 and 1996, acquired with handheld analog camcorders from small aircraft, were timed to imaging of the GRFM low- and high-water mosaics, and limited to within 600 km of Manaus. For the 1997 and 1999 flights, digital camcorder systems were installed in the Bandeirante survey plane operated by Brazil\'s National Institute for Space Research. The VOAM97 and VOAM99 surveys circumscribed the Brazilian Amazon, documenting ground conditions at resolutions on the order of 1m (wide-angle format) and 10 cm (zoom format) for wetlands, forests, savannas, and human-impacted areas. Global Positioning System (GPS) information encoded on the video audio track was extracted by mosaicking software that automatically generates geocoded digital mosaics from video clips. On the 1999 survey, a laser altimeter recorded profiles of terrain and vegetation canopy heights. A validation dataset was compiled from the videography for a portion of the GRFM mosaics extending 6 degrees by 4 degrees in longitude and latitude, using randomly selected points along flight lines. Other applications of the VOAM videography include acquisition of ground control points for image geolocation, creation of a high-resolution geocoded mosaic of a forest study area, forest biomass estimation, and rapid assessment of fire damage. Geocoded digital videography provides a cost-effective means of compiling high resolution validation datasets for land cover mapping in remote, cloud-covered regions.

Beginning Date:

1999-06-01

Ending Date:

1996-06-30

Metadata Last Updated on:

2012-07-31

Data Status:

In Preparation for Archive

Access Constraints:

Public

Data Center URL:

http://www.obt.inpe.br/videografia/

Distribution Contact(s):

mary@icess.ucsb.edu and affonso@ltid.inpe.br

Access Instructions:

Public

Data Access:

IMPORTANT: The LBA-ECO Project website is no longer being supported. Links to external websites may be inactive. Final data products from the LBA project can be found at the ORNL DAAC. Please follow the fair use guidelines found in the dataset documentation when using or citing LBA data.
Datafile(s):

The 1999 Amazon Videography data available via ORNL DAAC:  Search at ORNL DAAC
The 1999 VOAM (INPE):  http://www.obt.inpe.br/videografia/
Example video clip:  http://www.icess.ucsb.edu/LBA/archives/LC07/hess/IJRS2002_LH4_VOAM99/

Documentation/Other Supporting Documents:

Example video mosaic described:  http://www.icess.ucsb.edu/LBA/data/VIDEO/Slide7.JPG
browse jpg of example video clip:  http://www.icess.ucsb.edu/LBA/archives/LC07/hess/IJRS2002_LH4_VOAM99/example_video_clip/19990617_16525915_16533111_wg_lowres.jpg
Data Set User's Guide (Draft):  Search at ORNL DAAC
Early introductory material describing VOAM99:  http://www.icess.ucsb.edu/LBA/data/VIDEO/
readme.txt file for example video clip files:  http://www.icess.ucsb.edu/LBA/archives/LC07/hess/IJRS2002_LH4_VOAM99/example_video_clip/readme.txt
panel from LBA poster for VOAM99:  http://www.icess.ucsb.edu/LBA/data/VIDEO/LBA_poster_panel_digital_videography.pdf

Citation Information - Other Details:

Hess L.L., J.M. Melack, E.M.L.M. Novo, C.C.F. Barbosa, M. Gastil-Buhl. 2008. LBA-ECO LC-07 Validation Overflight for Amazon Mosaics (VOAM): June 1999. Data set. Available on-line [http://lba.cptec.inpe.br/] from LBA Data and Information System, National Institute for Space Research (INPE/CPTEC), Cachoeira Paulista, Sao Paulo, Brazil.

Keywords - Theme:

Parameter Topic Term Source Sensor
LAND COVER LAND SURFACE LAND USE/LAND COVER CANON X-1 DIGITAL CAMCORDERS DIGITAL VIDEO CAMERA
WETLANDS LAND SURFACE LAND USE/LAND COVER CANON X-1 DIGITAL CAMCORDERS DIGITAL VIDEO CAMERA
LAND COVER CLASSES LAND SURFACE LAND USE/LAND COVER CANON X-1 DIGITAL CAMCORDERS DIGITAL VIDEO CAMERA

Uncontrolled Theme Keyword(s):  ACCURACY ASSESSMENT;AERIAL VIDEOGRAPHY;AIRBORNE VIDEO;AMAZON;AMAZON BASIN;AREA;AREAS;BASIN;BIOMASS;B, aerial survey, aquatic macrophyte, aquatic macrophytes, classification, digital videography, flooded forest, flooding, floodplain, habitats, inundation, land cover classification, river, rivers, varzea, vegetation, video mosaic, wetland, wetlands

Keywords - Place (with associated coordinates):

Region
(click to view profile)
Site
(click to view profile)
North South East West
Amazon Basin Amazon Basin 4.00000 -12.00000 -44.00000 -68.00000

Related Publication(s):

Hess, L.L., E.M.L.M. Novo, D.M. Slaymaker, J. Holt, C. Steffen, D.M. Valeriano, L.A.K. Mertes, T. Krug, J.M. Melack, M. Gastil, C. Holmes, and C. Hayward. 2002. Geocoded digital videography for validation of land cover mapping in the Amazon basin. International Journal of Remote Sensing 23(7):1527-1555.

Hess, L.L., J.M. Melack, E.M.L.M. Novo, C.C.F. Barbosa, and M. Gastil. 2003. Dual-season mapping of wetland inundation and vegetation for the central Amazon basin. Remote Sensing of Environment, Vol. 87, No. 4, pp. 404-428.

Powell RL, Matzke N, de Souza C, Clark M, Numata I, Hess LL, Roberts DA, Clark M, Numata I, Hess LL, Roberts DA. 2004. Sources of error in accuracy assessment of thematic land-cover maps in the Brazilian Amazon. Remote Sensing of Environment, 90, 221-234.

Data Characteristics (Entity and Attribute Overview):

Data Characteristics:

The VOAM99 dataset consists of video clips and mosaics made from video clips.

The video files are in file format mp4.

The mosaic images are in file format tiff.



The full set of digital video is best accessed from the INPE website

http://www.obt.inpe.br/videografia/



An example video clip is available at

http://www.icess.ucsb.edu/LBA/archives/LC07/hess/IJRS2002_LH4_VOAM99/



The dataset is described in the reference (Hess, 2002).

________________________________________________________

Image Resolution:

(copied from Hess, 2002)

4.2. Resolution and swath width

Flying height for the VOAM99 survey ranged from 100 to 900 m, with a median

of 350 m. For segments where laser data was required, flying height was selected to maximize swath width while remaining within the range of the laser instrument and below the cloud ceiling. At the median flying height, swath width was about 550m (wide-angle) and 55m (zoom), with pixel dimensions of about 0.75m (wide) and 7.5 cm (zoom). Resolution of the VOAM99 video data was in general equivalent to pixel dimension, with the exception of occasional loss of focus over smooth water surfaces. On the high-resolution zoom footage, features such as individual branches, leaves, and grass stems are distinguishable.

Data Application and Derivation:

Data Application:

The VOAM99 dataset was used to validate three other LBA-ECO LC-07 data products: the Central Amazon Wetlands Mask, the Central Amazon Wetlands Habitat Map, and the Amazon Basinwide Wetlands Mask. (These are listed under Related Datasets.)



The VOAM99 data was also used by other LBA-ECO projects, including LC-20.

This data will also be used by LBA-ECO LC-32 projects.



The VOAM99 data can be used to generate ground control points of known geographic location in remote, unmapped, regions.



Data Derivation:

The GRFM JERS Mosaic was used to plan the route of the VOAM99 survey.

Quality Assessment (Data Quality Attribute Accuracy Report):

Quality Assessment:

Quality Assessment:



Geolocation accuracy and altitude measurement accuracy are discussed in Hess (2002) sections 4.3 and 4.4.





[Excerpt from p.1540] 4.3. Geolocation accuracy of VOAM97 and VOAM99 data

The absolute geolocation accuracy of mosaics generated from VOAM97 and

VOAM99 data is affected by errors from several sources.

1. Aircraft GPS location. For the real-time, diVerentially corrected GPS signal

received once per second during the VOAM99 survey, expected probabilities

of horizontal error are 67 to 73% that location error will be less than 0.5 m,

95 to 97% that it will be less than 1.0 m, and 99% that it will be less than 1.5 m.

The range of vertical error is 2 to 2.5 times as great, resulting in a 67 to 73% probability of vertical error less than 1.25 m, 95 to 97% probability of error less than 2.5 m, and 99% probability of error less than 3.75 m. For the VOAM97 survey, which was based on non-differentially corrected GPS readings every 2 s, horizontal error probabilities are estimated at 95% for errors <100m.

2. Frame centre location, pre-mosaicking. For VOAM99, calculation of the horizontal offset between aircraft location and frame centre location is affected by errors in GPS-based vertical position of the aircraft, in range to ground (measured by laser rangefinder), and in aircraft tip and tilt (measured by AHRS). At an aircraft height above ground of 350m and aircraft tip/tilt of

5 degrees, and assuming instrument errors of plus or minus 2.5m from the GPS, plus or minus 15 cm from the laser rangefinder and plus or minus 0.3 degrees from the AHRS, the resulting error in offset calculation would be 3 m, 2.5m of which is owing to error in tip/tilt measurement.

Adding this to the 1.0m horizontal error achieved 95 to 97% of the time

for aircraft position yields an error of up to 4m in horizontal positions of

frame centres. Air turbulence would add further error to frame centre location.

The 1997 survey did not include AHRS or laser measurements. Again assuming

an aircraft height above ground of 350m and aircraft tip/tilt of 5 degrees, a horizontal error of plus or minus 43m would result from the lack of correction owing to tip/tilt.

3. Pixel location, post-mosaicking. The amount of error introduced during

mosaicking is estimated to be on the order of two or three pixels, or about

1 to 3m for wide-angle mosaics at typical flight altitudes, for the centre track of the mosaic. Relative and absolute geolocation errors can be expected to

increase along the margins of mosaics, owing to lens distortions and to terrain

height effects where terrain height varies across the video swath. Optical

distortion models for the lenses used in the two surveys are not currently

available.

Because of the number of interacting factors affecting geolocation accuracy, and

the large amount of data collected, a comprehensive assessment of geolocation error is not feasible for the VOAM97 and VOAM99 datasets. Comparison with field GPS measurements for a small number of sites indicates that absolute errors are in the range of 5 to 10m (1999) and 50 to 150m (1997) along the centre third of mosaicked swaths.

Process Description:

Data Acquisition Materials and Methods:

For detailed description of Materials and Methods used, please see (Hess, 2002), from which the following was excerpted.</p>

<p>[caption, Figure 3.] Digital video acquisition system for VOAM99 survey. OmniSTAR real-time, differential GPS signal received by Trimble 132 GPS using externally mounted L-band receiver was converted to SMPTE format by Horita GPS3 time-code generator, for encoding on audio tracks of digital videotapes. GPS data were also used for continuous updating of flight track on navigation computer. Wide-angle and zoom format videography acquired simultaneously by two Canon XL-1 digital camcorders was recorded in mini-DV format and viewed using Sony GV-D900 Video Walkman VCRs. Data streams from Watson Industries BA303 AHRS (attitude and heading reference system),

Laser Atlanta Advantage laser rangefinder, and GPS were time-stamped and recorded by flight data acquisition computer for post-flight processing.</p>

<p>[from p.1533] Acquisition. The 1999 survey, again in the INPE Bandeirante survey plane, was conducted using a video acquisition system (Figure 3) developed by the departments of Natural Resource Conservation and Computer Science of the University of Massachusetts (UMass) Amherst (Schultz et al 1999a) . A laser rangefinder (904 nm wavelength) measured aircraft height above ground or canopy, and an attitude and heading reference system (AHRS) measured aircraft tip and tilt. Aircraft position could then be projected to ground coordinates corrected for deviations from a vertical viewing

angle. To improve the accuracy with which aircraft position was known, the UMass

system GPS was upgraded to receive a real-time, differentially corrected GPS signal from the Omnistar commercial GPS satellite network. Both VOAM99 camcorders were digital and both were vertically oriented, one in wide-angle mode and one in zoom mode. The camcorders, laser and AHRS were mounted on an INPE-built frame. Camcorder shutter speeds were fixed at 0.001 s (wide-angle) and 0.0005 s

(zoom).</p>







Also see:

http://www.obt.inpe.br/videografia/the_1999_voam.htm

References:

Hess, L.L., E.M.L.M. Novo, D.M. Slaymaker, J. Holt, C. Steffen, D.M. Valeriano, L.A.K. Mertes, T. Krug, J.M. Melack, M. Gastil, C. Holmes, and C. Hayward. 2002. Geocoded digital videography for validation of land cover mapping in the Amazon basin. International Journal of Remote Sensing 23(7):1527-1555.



Hess LL, Melack JM, Novo EMLM, Barbosa CCF, Gastil M. (2003) Dual-season mapping of wetland inundation and vegetation for the central Amazon basin. Remote Sensing of Environment, 87, 404-428.

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