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Collection:
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NASA Planetary Photo Journal Collection
Collection
NASA Planetary Photo Journal Collection
Collection
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Title:
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Global Map of Ganymede
Title
Global Map of Ganymede
Title
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Original Caption Released with Image:
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The images used for the base of this Ganymede globe were chosen from coverage supplied by the Galileo solid-state imaging (SSI) camera and Voyager 1 and 2 spacecraft. The monochrome and color data were both processed using Integrated Software for Imagers and Spectrometers (ISIS). The individual images were radiometrically calibrated and photometrically normalized using a Lunar-Lambert function with empirically derived values. A linear correction based on the statistics of all overlapping areas was then applied to minimize image brightness variations. The image data were selected on the basis of overall image quality, reasonable original input resolution (from 20 km/pixel for gap fill to as much as 180 m/pixel), and availability of moderate emission/incidence angles for topography and albedo. The black and white monochrome base mosaic was constructed separately from the three-band color mosaic. Although consistency was achieved where possible, different filters were included for monochrome global image coverage as necessary: clear for Voyager 1 and 2; clear, near-IR (757 nm), and green (559 nm) for Galileo SSI. Individual images were projected to a Sinusoidal Equal-Area projection at an image resolution of 1 km/pixel. The global color mosaic was processed in Sinusoidal projection with an image resolution of 6 km/pixel. The color utilized the SSI filters 1-micron(991 nm) wavelength for red, SSI 559 nm for green, and SSI 413 nm for violet. Where SSI color coverage was lacking in the longitude range of 210°-250°, Voyager 2 wide-angle images were included to complete the global coverage. The chosen filters for the Voyager 2 data were ~530 nm for green, and ~480-500 nm for blue. The red band was synthesized in this area based on statistics calculated from the surrounding SSI 1-micron (991 nm) data and SSI and Voyager data in the blue and green bands. The final global color mosaic was then scaled up to 1 km/pixel and merged with the monochrome mosaic. The north pole and south pole regions that lack digital color coverage have been completed with the monochrome map coverage. The final global mosaic was then reprojected so that the entire surface of Ganymede is portrayed in a manner suitable for the production of a globe. A specialized program was used to create the "flower petal" appearance of the images; the area of each petal from 0 to 75 degrees latitude is in the Transverse Mercator projection, and the area from 75 to 90 degrees latitude is in the Lambert Azimuthal Equal-Area projection. The projections for adjacent petals overlap by 2 degrees of longitude, so that some features are shown twice. Names shown on the globe are approved by the International Astronomical Union. The number, size, and placement of text were chosen for a 9-inch globe. A complete list of Ganymede nomenclature can be found at the Gazetteer of Planetary Nomenclature at http://planetaryname s.wr.usgs.gov. The northern hemisphere is shown on the left, and the southern hemisphere
Original_Caption_Rel eased_with_Image
The images used for the base of this Ganymede globe were chosen from coverage supplied by the Galileo solid-state imaging (SSI) camera and Voyager 1 and 2 spacecraft. The monochrome and color data were both processed using Integrated Software for Imagers and Spectrometers (ISIS). The individual images were radiometrically calibrated and photometrically normalized using a Lunar-Lambert function with empirically derived values. A linear correction based on the statistics of all overlapping areas was then applied to minimize image brightness variations. The image data were selected on the basis of overall image quality, reasonable original input resolution (from 20 km/pixel for gap fill to as much as 180 m/pixel), and availability of moderate emission/incidence angles for topography and albedo. The black and white monochrome base mosaic was constructed separately from the three-band color mosaic. Although consistency was achieved where possible, different filters were included for monochrome global image coverage as necessary: clear for Voyager 1 and 2; clear, near-IR (757 nm), and green (559 nm) for Galileo SSI. Individual images were projected to a Sinusoidal Equal-Area projection at an image resolution of 1 km/pixel. The global color mosaic was processed in Sinusoidal projection with an image resolution of 6 km/pixel. The color utilized the SSI filters 1-micron(991 nm) wavelength for red, SSI 559 nm for green, and SSI 413 nm for violet. Where SSI color coverage was lacking in the longitude range of 210°-250°, Voyager 2 wide-angle images were included to complete the global coverage. The chosen filters for the Voyager 2 data were ~530 nm for green, and ~480-500 nm for blue. The red band was synthesized in this area based on statistics calculated from the surrounding SSI 1-micron (991 nm) data and SSI and Voyager data in the blue and green bands. The final global color mosaic was then scaled up to 1 km/pixel and merged with the monochrome mosaic. The north pole and south pole regions that lack digital color coverage have been completed with the monochrome map coverage. The final global mosaic was then reprojected so that the entire surface of Ganymede is portrayed in a manner suitable for the production of a globe. A specialized program was used to create the "flower petal" appearance of the images; the area of each petal from 0 to 75 degrees latitude is in the Transverse Mercator projection, and the area from 75 to 90 degrees latitude is in the Lambert Azimuthal Equal-Area projection. The projections for adjacent petals overlap by 2 degrees of longitude, so that some features are shown twice. Names shown on the globe are approved by the International Astronomical Union. The number, size, and placement of text were chosen for a 9-inch globe. A complete list of Ganymede nomenclature can be found at the Gazetteer of Planetary Nomenclature at http://planetaryname s.wr.usgs.gov. The northern hemisphere is shown on the left, and the southern hemisphere
Original Caption Released with Image
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Original Caption Released with Image:
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is shown on the right.
Original_Caption_Rel eased_with_Image
is shown on the right.
Original Caption Released with Image
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Produced By:
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U.S. Geological Survey
Produced_By
U.S. Geological Survey
Produced By
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Mission:
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Voyager
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Mission:
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Galileo
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Spacecraft:
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GALILEO ORBITER
Spacecraft
GALILEO ORBITER
Spacecraft
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Spacecraft:
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VOYAGER 1
Spacecraft
VOYAGER 1
Spacecraft
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Spacecraft:
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VOYAGER 2
Spacecraft
VOYAGER 2
Spacecraft
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Target Name:
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Ganymede
Target_Name
Ganymede
Target Name
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Is a satellite of:
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Jupiter
Is_a_satellite_of
Jupiter
Is a satellite of
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Instrument:
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Imaging Science Subsystem - Narrow Angle
Instrument
Imaging Science Subsystem - Narrow Angle
Instrument
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Instrument:
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Imaging Science Subsystem
Instrument
Imaging Science Subsystem
Instrument
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Product Size:
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8817 samples x 4382 lines
Product_Size
8817 samples x 4382 lines
Product Size
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facet_what:
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Jupiter
facet_what
Jupiter
facet_what
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facet_what:
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Voyager
facet_what
Voyager
facet_what
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facet_what:
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Voyager 2
facet_what
Voyager 2
facet_what
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facet_what:
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Voyager 1
facet_what
Voyager 1
facet_what
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facet_what:
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Galileo
facet_what
Galileo
facet_what
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facet_what:
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Galileo Orbiter
facet_what
Galileo Orbiter
facet_what
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facet_what:
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Solid-State Imaging
facet_what
Solid-State Imaging
facet_what
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facet_what:
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Ganymede
facet_what
Ganymede
facet_what
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facet_what:
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Imaging Science Subsystem (ISS)
facet_what
Imaging Science Subsystem (ISS)
facet_what
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facet_what:
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Ganymede (Jupiter Moon)
facet_what
Ganymede (Jupiter Moon)
facet_what
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facet_where:
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Jupiter
facet_where
Jupiter
facet_where
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facet_where:
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Ganymede
facet_where
Ganymede
facet_where
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facet_where:
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Jet Propulsion Laboratory (JPL)
facet_where
Jet Propulsion Laboratory (JPL)
facet_where
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Image #:
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PIA03781
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UID:
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SPD-PHOTJ-PIA03781
UID
SPD-PHOTJ-PIA03781
UID
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orignial url:
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orignial_url
orignial url
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