Resources for Teachers

Construct 3-D Globes

Download, print, and make your own paper globes of planets and moons.

Ganymede Voyager Galileo Image Mosaic Globe || Europa Voyager / Galileo Image Mosaic Globe || Mars Global Surveyor Color-Coded Contour Map || Mars Global Surveyor MOLA Topographic Map || Moon Clementine Topographic Maps || Venus Magellan Globe || Moon Clementine Topographic Globe || Mars Viking Globe || Mars Global Surveyor MOLA Globe || Mars Mini Globes || Callisto Voyager / Galileo Image Mosaic Globe || Io Voyager / Galileo Image Mosaic Globe

 

The images used for the base of this 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. The northern hemisphere is shown on the left, and the southern hemisphere is shown on the right.

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The images used for the base of this globe were chosen from coverage supplied by the Galileo solid-state imaging (SSI) camera and Voyager 1 and 2 spacecraft. 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 200 m/pixel), and availability of moderate emission/incidence angles for topography. Although consistency was achieved where possible, different filters were included for global image coverage as necessary: clear/blue for Voyager 1 and 2, and 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 500 m/pixel, and a final global mosaic was constructed in this same Sinusoidal projection. The global mosaic was then reprojected so that the entire surface of Europa 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 Europa nomenclature can be found at the Gazetteer of Planetary Nomenclature. The northern hemisphere is shown on the left, and the southern hemisphere is shown on the right.

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This map is based on data from the Mars Orbiter Laser Altimeter (MOLA) (Smith and others, 2001), an instrument on NASA's Mars Global Surveyor (MGS) spacecraft (Albee and others, 2001). The image used for the base of this map represents more than 600 million measurements gathered between 1999 and 2001, adjusted for consistency (Neumann and others, 2001, 2002) and converted to planetary radii. These have been converted to elevations above the areoid as determined from a martian gravity field solution GMM2 (Lemoine and others, 2001), truncated to degree and order 50, and oriented according to current standards (see below). The average accuracy of each point is originally ~100 meters in horizontal position, and ~1 meter in radius (Neumann, 2001). However, the total elevation uncertainty is at least ±3 m due to the global error in the areoid (±1.8 meters according to Lemoine and others, 2001) and regional uncertainties in its shape (communication from Neumann, 2002). The measurements were converted into a digital elevation model (DEM) (communication from Neumann, 2002; Neumann and others, 2001; Smith and others, 2001) using Generic Mapping Tools software (Wessel and Smith, 1998), with a resolution of 0.015625 degrees per pixel or 64 pixels per degree. In projection, the pixels are 926.17 meters in size at the equator.

The Mercator projection is used between latitudes ±57°, with a central meridian at 0° and latitude equal to the nominal scale at 0°. The Polar Stereographic projection is used for the polar regions north of the +55° parallel and south of the -55° parallel with a central meridian set for both at 0°. The adopted equatorial radius is 3,396.19 km (Duxbury and others 2002; Seidelmann and others 2002).

The MOLA data were initially referenced to an internally consistent inertial coordinate system, derived from tracking of the MGS spacecraft. By adopting appropriate values for the orientation of Mars as defined by the International Astronomical Union (IAU) and the International Association of Geodesy (IAG) (Seidelmann and others, 2002), these inertial coordinates were converted into the planet-fixed coordinates (longitude and latitude) used on this map. These values include the orientation of the north pole of Mars (including the effects of precession), the rotation rate of Mars, and a value for W0 of 176.630°, where W0 is the angle along the equator to the east, between the 0° meridian and the equator's intersection with the celestial equator at the standard epoch J2000.0 (Seidelmann and others, 2002). This value of W0 was chosen (Duxbury and others, 2002) in order to place the 0° meridian through the center of the small (~500 m) crater Airy-0, located in the crater Airy (de Vaucouleurs and others, 1973; Seidelmann and others, 2002). Longitude increases to the east, and latitude is planetocentric as allowed by IAU/IAG standards (Seidelmann and others, 2002) and in accordance with current NASA and USGS standards (Duxbury and others, 2002). A secondary grid (printed in red) has been added to the map as a reference to the west longitude/planetographic latitude system that is also allowed by IAU/IAG standards (Seidelmann and others, 2002) and has also been used for Mars. The figure adopted to compute this secondary grid is an oblate spheroid with an equatorial radius of 3,396.19 km and a polar radius of 3,376.2 km (Duxbury and others, 2002; Seidelmann and others, 2002).

To create the topographic base image, the original DEM produced by the MOLA team in Simple Cylindrical projection with a resolution of 64 pixels per degree was projected into the Mercator and Polar Stereographic pieces. A shaded relief was generated from each DEM with a sun angle of 30° from horizontal and a sun azimuth of 270°, as measured clockwise from north, and a vertical exaggeration of 100%. Illumination is from the west, which follows a long-standing USGS tradition for planetary maps. This allows for continuity in the shading between maps and quadrangles, and most closely resembles lighting conditions found on imagery. The DEM values were then mapped to a smooth global color look-up table. Note that the chosen color scheme simply represents elevation changes and is not intended to imply anything about surface characteristics (e.g., past or current presence of water or ice). These two files were then merged and scaled to 1:25 million for the Mercator portion and 1:15,196,708 for the two Polar Stereographic portions, with a resolution of 300 dots per inch. The projections have a common scale of 1:13,923,113 at ±56° latitude. Contours were created from the DEM at a 1-kilometer interval. Contours for features with a diameter of 3 km or less (features too small for this map scale) were removed. The contours were then simplified by removing points along the contours spaced less than 1 km apart.

Names on this sheet are approved by the IAU and have been applied for features clearly visible at the scale of this map. For a complete list of the IAU-approved nomenclature for Mars, see the Gazetteer of Planetary Nomenclature. Font color was chosen for readability. Names followed by an asterisk are provisionally approved.

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This map is based on data from the Mars Orbiter Laser Altimeter (MOLA) (Smith and others, 2001), an instrument on NASA's Mars Global Surveyor (MGS) spacecraft (Albee and others, 2001). The image used for the base of this map represents more than 600 million measurements gathered between 1999 and 2001, adjusted for consistency (Neumann and others, 2001, 2002) and converted to planetary radii. These have been converted to elevations above the areoid as determined from a martian gravity field solution GMM2 (Lemoine and others, 2001), truncated to degree and order 50, and oriented according to current standards (see below). The average accuracy of each point is originally ~100 meters in horizontal position, and ~1 meter in radius (Neumann, 2001). However, the total elevation uncertainty is at least ±3 m due to the global error in the areoid (±1.8 meters according to Lemoine and others, 2001) and regional uncertainties in its shape (communication from Neumann, 2002). The measurements were converted into a digital elevation model (DEM) (communication from Neumann, 2002; Neumann and others, 2001; Smith and others, 2001) using Generic Mapping Tools software (Wessel and Smith, 1998), with a resolution of 0.015625 degrees per pixel or 64 pixels per degree. In projection, the pixels are 926.17 meters in size at the equator.

The Mercator projection is used between latitudes ±57°, with a central meridian at 0° and latitude equal to the nominal scale at 0°. The Polar Stereographic projection is used for the polar regions north of the +55° parallel and south of the -55° parallel with a central meridian set for both at 0°. The adopted equatorial radius is 3,396.19 km (Duxbury and others 2002; Seidelmann and others 2002).

The MOLA data were initially referenced to an internally consistent inertial coordinate system, derived from tracking of the MGS spacecraft. By adopting appropriate values for the orientation of Mars as defined by the International Astronomical Union (IAU) and the International Association of Geodesy (IAG) (Seidelmann and others, 2002), these inertial coordinates were converted into the planet-fixed coordinates (longitude and latitude) used on this map. These values include the orientation of the north pole of Mars (including the effects of precession), the rotation rate of Mars, and a value for W0 of 176.630°, where W0 is the angle along the equator to the east, between the 0° meridian and the equator's intersection with the celestial equator at the standard epoch J2000.0 (Seidelmann and others, 2002). This value of W0 was chosen (Duxbury and others, 2002) in order to place the 0° meridian through the center of the small (~500 m) crater Airy-0, located in the crater Airy (de Vaucouleurs and others, 1973; Seidelmann and others, 2002). Longitude increases to the east, and latitude is planetocentric as allowed by IAU/IAG standards (Seidelmann and others, 2002) and in accordance with current NASA and USGS standards (Duxbury and others, 2002). A secondary grid (printed in red) has been added to the map as a reference to the west longitude/planetographic latitude system that is also allowed by IAU/IAG standards (Seidelmann and others, 2002) and has also been used for Mars. The figure adopted to compute this secondary grid is an oblate spheroid with an equatorial radius of 3,396.19 km and a polar radius of 3,376.2 km (Duxbury and others, 2002; Seidelmann and others, 2002).

To create the topographic base image, the original DEM produced by the MOLA team in Simple Cylindrical projection with a resolution of 64 pixels per degree was projected into the Mercator and Polar Stereographic pieces. A shaded relief was generated from each DEM with a sun angle of 30° from horizontal and a sun azimuth of 270°, as measured clockwise from north, and a vertical exaggeration of 100%. Illumination is from the west, which follows a long-standing USGS tradition for planetary maps. This allows for continuity in the shading between maps and quadrangles, and most closely resembles lighting conditions found on imagery. The DEM values were then mapped to a smooth global color look-up table. Note that the chosen color scheme simply represents elevation changes and is not intended to imply anything about surface characteristics (e.g., past or current presence of water or ice). These two files were then merged and scaled to 1:25 million for the Mercator portion and 1:15,196,708 for the two Polar Stereographic portions, with a resolution of 300 dots per inch. The projections have a common scale of 1:13,923,113 at ±56° latitude.

Names on this sheet are approved by the IAU and have been applied for features clearly visible at the scale of this map. For a complete list of the IAU-approved nomenclature for Mars, see the Gazetteer of Planetary Nomenclature. Font color was chosen for readability. Names followed by an asterisk are provisionally approved.

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This sheet is one in a series of topographic maps that presents colorcoded topographic data digitally merged with shaded relief data.

The figure for the Moon, used for the computation of the map projection, is a sphere with a radius of 1737.4 km (Seidelmann and others, 2002). Because the Moon has no surface water, and hence no sea level, the datum (the 0 km contour) for elevations is defined as the radius of 1737.4 km. Coordinates are based on the mean Earth/polar axis (M.E.) coordinates system, the z axis is the axis of the Moon’s rotation, and the x axis is the mean Earth direction. The center of mass is the origin of the coordinate system (Davies and Colvin, 2000). The equator lies in the x–y plane and the prime meridian lies in the x–z plane with east longitude values being positive.

The projection is Lambert Azimuthal Equal Area Projection. The scale factor at the central latitude and central longitude point is 1:10,000,000. For the near side hemisphere the central latitude and central longitude point is at 0° and 0°. For the far side hemisphere the central latitude and central longitude point is at 0° and 180°.

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Venus Magellan Globe (JPEG) (10.3 MB)

The images used for the base of this globe show the northern and southern hemispheres of Venus as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of these images is about 3 kilometers. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from Soviet Venera 15 and 16 spacecraft in the northern quarter of the planet, with images from the Earth-based Arecibo radar in a region centered roughly on 0 degrees latitude and 0 degrees longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions.

The images are presented in a projection that portrays the entire surface of Venus 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 are approved by the International Astronomical Union.

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The photomosaic that forms the base for this globe combines a gray-shaded relief airbrush image with color-coded topographic data. The shaded relief data provide interpretations of lunar morphology based on lunar images and were used as a grayscale image for this global mosaic. Topographic data from the Clementine laser altimeter were combined with topographic data collected photogrammetrically from Clementine stereo images. The resulting topographic product was colored based on elevation value and combined with the shaded relief data to form the final photomosaic.

The shaded relief data were originally published as a series of 1:5 million shaded relief maps. This series included three U.S. Geological Survey maps: I-1218-B, Shaded Relief Map of the Lunar Far Side, 1980; I-1326-A, Shaded Relief Map of the Lunar Polar Regions, 1981; and I-2276, Sheet 2 of 2, Shaded Relief Map of the Lunar Near Side, 1992. These data were digitized and mosaicked into a single digital file. An area of approximately 500,000 km2 near the south pole was not visible in any pre-Clementine images and is blank on the published map. The digitized shaded relief base was updated to show features in this area, based on the Clementine mosaic and recent Earth-based radar images.

The digital shaded relief data were registered to a mosaic produced from Clementine images. This registration process consisted of picking points of features that were visible in both the shaded relief data and the Clementine mosaic. To accomplish this, the files were divided into three areas; north pole, equatorial region, and south pole. They were aligned first in the equatorial region and then in the polar regions. Within the equatorial region, an area from 60° south to 60° north, approximately 1000 points were picked. Within the north polar region, an area from 57° north to 90° north, approximately 1900 points were picked. Within the south polar region, an area from 57° south to 90° south, approximately 1100 points were picked. These points were used to reproject the shaded relief map to match the Clementine mosaic.

The Clementine LASER altimeter collected data between 79° south and 81° north. The along track spacing varied: over some smooth mare surfaces an along-track spacing of 20 km was achieved; where the instrument lost lock over some rough highland terrain, the spacing degraded to 100 km. The across-track spacing was based on the orbital track and is approximately 60 km at the equator. Elevation values were collected at 72,548 points by the Clementine LASER altimeter. These points were used to interpolate a global topographic gridded digital terrain model for the lunar surface. Because the altimeter points were sparse in the polar regions, the polar regions from this digital terrain model were clipped and only data between 75° south and 75° north were used in this photomosaic. To fill in the polar regions, topographic data collected photogrammetrically from Clementine imagery were used.

The Clementine mission collected both oblique and vertical images over the polar regions; these images form stereo pairs that can be used photogrammetrically to collect topographic data. Over the south polar region (90° south - 64° south latitude) topographic data were collected from 667 stereo models. In the north polar region (90° north - 64° north latitude) there were 640 stereo models. Topographic data were collected within each stereo model with a post spacing of 1 km in the x and y directions. This resulted in 1,720,922 points being collected in the south polar region and 1,437,360 points being collected in the north polar region. These data were merged and vertically transformed to align with the Clementine altimeter data. In certain areas, no topographic data were collected; those areas were not colored and the shaded relief image is shown as a grayscale image.

The photomosaic is presented in a projection that portrays the entire lunar surface in a manner suitable for the production of a globe; the number, size, and placement of text annotations were chosen to provide a general orientation of prominent features on a 12-inch globe. Features are labeled with names approved by the International Astronomical Union (for a complete list of lunar nomenclature, see Gazetteer of Planetary Nomenclature). A specialized program was used to create the "flower petal" appearance of the photomosaic; the areas 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 northern hemisphere is shown on the left and the southern hemisphere is shown on the right.

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Mars Viking Globe (JPEG) (6 MB)

The photomosaic that forms the base for this globe was created by merging two global digital image models (DIM's) of Mars, a medium-resolution monochrome mosaic processed to emphasize topographic features, and a lower resolution color mosaic emphasizing color and albedo variations.

 

The medium-resolution (1/256 or roughly 231 m/pixel) monochromatic image model was constructed from about 6,000 images having resolutions of 150-350 m/pixel and oblique illumination (Sun 20 ° -45 ° above the horizon). Radiometric processing was intended to suppress or remove the effects of albedo variations through the use of a high-pass divide filter, followed by photometric normalization so that the contrast of a given topographic slope would be approximately the same in all images.

 

The global color mosaic was assembled at 1/64 or roughly 864 m/pixel from about 1,000 red- and green-filter images having 500-1,000 m/pixel resolution. These images were first mosaicked in groups, each taken on a single orbit of the Viking spacecraft. The orbit mosaics were then processed to remove spatially and temporally varying atmospheric haze in the overlap regions. After haze removal, the per-orbit mosaics were photometrically normalized to equalize the contrast of albedo features and mosaicked together with cosmetic seam removal. The medium-resolution DIM was used for geometric control of this color mosaic. A green-filter image was synthesized by weighted averaging of the red- and violet-filter mosaics. Finally, the product seen here was obtained by multiplying each color image by the medium-resolution monochrome image. The color balance selected for images in this map series was designed to be close to natural color for brighter, redder regions, such as Arabia Terra and the Tharsis region, but the data have been stretched so that the relatively dark regions appear darker and less red than they actually are.

 

The images are presented in a projection that portrays the entire surface of Mars in a manner suitable for the production of a globe; the number, size, and placement of text annotations were chosen for a 12-inch globe (shown above, center image, 23 kB). Prominent features are labeled with names approved by the International Astronomical Union. 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 northern hemisphere of Mars is shown on the left, and the southern hemisphere on the right.

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The color shaded relief image used as the base for this globe has a resolution of 32 pixels per degree (approximately 1850 m/pixel), and was produced and supplied by the MOLA Science Team. The image is shaded as if illuminated everywhere from the west. The elevations represented in color are with respect to a gravitational equipotential surface whose mean equatorial radius is that of the topography. The Astrogeology Research Program of the U.S. Geological Survey reprojected the image into the format displayed above.

The images are presented in a projection that portrays the entire surface of Mars in a manner suitable for the production of a globe; the number, size, and placement of text annotations were chosen for a 12-inch globe. Prominent features are labeled with names approved by the International Astronomical Union. 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 northern hemisphere of Mars is shown on the left, and the southern hemisphere on the right.

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Mars Mini Globes (PDF) (2.41 MB)

Project sheet with instructions for creating the Viking and Global Surveyor Mars globes using tennis balls.

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The images used for the base of this globe were chosen from the best image quality and moderate resolution coverage supplied by Galileo SSI and Voyager 1 and 2 (Batson, 1987; Becker and others, 1998; Becker and others, 1999; Becker and others, 2001). The digital map was produced using Integrated Software for Imagers and Spectrometers (ISIS) (Eliason, 1997; Gaddis and others, 1997; Torson and Becker, 1997). The individual images were radiometrically calibrated and photometrically normalized using a Lunar-Lambert function with empirically derived values (McEwen, 1991; Kirk and others, 2000). 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 150 m/pixel), and availability of moderate emission/incidence angles for topography. Although consistency was achieved where possible, different filters were included for global image coverage as necessary: clear for Voyager 1 and 2; clear and green (559 nm) for Galileo SSI. Individual images were projected to a Sinusoidal Equal-Area projection at an image resolution of 1.0 kilometer/pixel, and a final global mosaic was constructed in this same projection. The final mosaic was enhanced using commercial software.

The global mosaic was then reprojected so that the entire surface of Callisto 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 Callisto nomenclature can be found at the Gazetteer of Planetary Nomenclature. In the image, the northern hemisphere is shown on the left, and the southern hemisphere is shown on the right.

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A global monochrome mosaic of the best resolution images from both Galileo and Voyager 1 was created that includes 51 Voyager 1 images with spatial resolutions sometimes exceeding the 1 km/pixel scale of the final mosaic. Although the subjovian hemisphere of Io was poorly seen by Galileo, superbly detailed Voyager 1 images cover longitudes from 240°W to 40°W and the nearby southern latitudes. Image resolutions in the mosaic range from 1.0 to 10 km/pixel along the equator, with the poorest coverage centered on longitude 50° W.

To present more information-rich views of Io, the global color derived from the Galileo color images was superimposed on the more detailed, higher resolution monochrome (Galileo/Voyager 1) mosaic. The procedure adopted was to calculate color ratio images from the Galileo data and apply them to the monochrome mosaic, requiring that the color ratios of the composite images match the color ratios of the Galileo data. The Galileo SSI camera's silicon CCD was sensitive to longer wavelengths than the vidicon cameras of Voyager, so distinctions between red and yellow hues can be more easily discerned.

The global mosaic was reprojected so the entire surface of Io 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 Io nomenclature can be found at the Gazetteer of Planetary Nomenclature. The northern hemisphere is shown on the left, and the southern hemisphere is shown on the right.

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