Io Galileo SSI Global Color Merge Mosaic 1km v1
Product Information:
This global false color mosaic was constructed from low phase angle violet, green, and near-infrared (756 nanometer) images from orbits G2, E6, C9, and C21 of the Galileo spacecraft and its Solid-State Imaging (SSI) camera. The images were calibrated using the best end-of-mission calibration information, corrected empirically for limb-darkening, and map projected using the camera-pointing corrections of Archinal et al. (2001). The co-registered color images were next hand-edited to remove topographic shadows and pixels too near the limb, and mosaicked using a numerical procedure that reduces the mismatch at the seams.
This mosaic represents our best understanding of Io's color as pictured during the Galileo Mission. The true colors that would be visible to the eye are similar but much more muted than shown here. The spatial resolution of the mosaic ranges from 1.3 to 21 kilometers per pixel (km) at the equator, with the poorest resolution on the Jupiter-facing hemisphere of Io.
Mission and Instrument Information:
Galileo launched on October 18, 1989 from the Kennedy Space Center in Florida aboard the space shuttle Atlantis with the aim to study Jupiter and its moons. It arrived at Jupiter on December 7th, 1995 and ended when the spacecraft entered Jupiter’s atmosphere on September 21, 2003. Galileo made seven flybys of Io during its fourteen-year mission in the Jovian system.
Galileo's Solid-State Imaging (SSI) experiment was designed to study Jupiter and it’s satellites using multi-spectral, high-resolution, charge-coupled device (CCD) camera. The camera was operated in eight filtered band passes from 350-1100nm, the eight-position filter wheel consisted of three broad-band filters: violet(404nm), green(559nm), and red(671nm). The broad-band filters allowed for the reconstruction of visible color photographs. The use of a CCD permitted the SSI to have an image geometry which was independent of brightness gradients, greater sensitivity to incident photons, and a wider spectral range than any camera previously flown on a planetary mission.
References:
Archinal, B. A., Davies, M. E., Colvin, T. R., Becker, T. L., Kirk, R. L., & Gitlin, A. R. (2001). An Improved Rand-USGS control network and size determination for IO. Paper presented at the 32nd Lunar and Planetary Science Conference, Lunar and Planetary Institute, Houston, TX. https://www.lpi.usra.edu/meetings/lpsc2001/pdf/1746.pdf
Barth, B., Radebaugh, J., & Christiansen, E. H. (2009). Classification of Io's Paterae: Active vs Inactive. Paper presented at the 40th Lunar and Planetary Institute Science Conference, Lunar and Planetary Institute, Houston, TX. https://www.lpi.usra.edu/meetings/lpsc2009/pdf/2397.pdf
Becker, T. L., & Geissler, P. E. (2005). Galileo Global Color Mosaics of Io. Paper presented at the 36th Lunar and Planetary Science Conference, Lunar and Planetary Institute, Houston, TX. http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1862.pdf
Belton, M. J. S., Klassen, K. P., Clary, M. C., Anderson, J. L., Anger, C. D., Carr, M. H., Chapman, C. R., et al. (1992). The Galileo Solid-State Imaging experiment. Space Science Reviews, 60(1-4), 413-455. https://doi.org/10.1007/BF00216864
Geissler, P. E., McEwan, A. S., Keszthelyi, L., Lopes-Gautier, R., Granahan, J., & Simonelli, D. P. (1999). Global color variations on Io. Icarus, 140(2), 265–282. https://doi.org/10.1006/icar.1999.6128
Soderblom, L. A., Edwards, K., Eliason, E. M., Sanchez, E. M., & Charette, M. P. (1978). Global color variations on the Martian surface. Icarus, 34(3), 446-464. https://doi.org/10.1016/0019-1035(78)90037-4
Veeder, G. J., Davies, A. G., Matson, D. L., & Johnson, T. V. (2009). Io: Heat flow from dark volcanic fields. Icarus, 204(1), 239-253. https://doi.org/10.1016/j.icarus.2009.06.027
Williams, D. A., Keszthelyi, L. P., Crown, D. A., Yff, J. A., Jaeger, W. L., Schenk, P. M., Geissler, P. E., & Becker, T. L. (2011). Volcanism on Io: New insights from global geologic mapping. Icarus, 214(1), 91-112. https://doi.org/10.1016/j.icarus.2011.05.007
- Publisher
- USGS Astrogeology Science Center
- Author
- USGS Astrogeology Science Center
- Originator
- Group
- PDS
- Added to Astropedia
- 14 March 2012
- Modified
- 3 February 2020
General
- Purpose
This mosaic updates Voyager mission global maps with Galileo Solid-State Imaging (SSI) data of superior resolution and geometric fidelity. The color mosaic improves the previous product of Geissler (1999) [2]by using later, higher resolution images with better geometric control and a more consistent range of phase angles. This product has been used as a base to map global geologic units [3], paterae [4], and volcanic fields [5] and as a base map for formal planetary nomenclature. An animated globe produced from the merged mosaic is available from NASA’s Planetary Photojournal http://photojournal.jpl.nasa.gov/catalog/PIA09257.
- Geospatial Data Presentation Form
- Global Mosaic, Remote-sensing Data
- Online Linkage
- https://planetarymaps.usgs.gov/mosaic/Io_Galileo_SSI_Global_Mosaic_ClrMerge_1km.tif
- Native Data Set Environment
- ISIS v3
- Supplemental Information
- http://photojournal.jpl.nasa.gov/catalog/PIA09257
Keywords
- System
- Jupiter
- Target
- Io
- Theme
- Geographic Information System (GIS), Image Processing, Remote Sensing, Satellites
- Mission
- Galileo, Voyager
- Instrument
- SSI, ISS
Contact and Distribution
- Access Constraints
- public domain
- Use Constraints
- None
Data Status and Quality
- Currentness Reference
- Publication date
- Progress
- Complete
- Update Frequency
- None planned
- Logical Consistency Report
- All data were projected to a triaxial ellipsoid shape model using the best available Galileo control network (Archinal, B.A., Davies, M.E., Colvin, T.R., Becker, T.L., Kirk, R.L., Gitlin, A.R., 2001. An improved RAND-USGS control network and size determination for Io. Lunar Planet. Sci. XXXII. Abstract #1746). This network suffers from a lack of control points in the region of 320° to 20° (east) longitude. The Voyager 1 images of regions west of 0° longitude appeared displaced from the positions predicted from the control net derived from the solution of the combined Galileo and Voyager data set. We suspect that the discrepancy arises from regional topography west of the sub-Jupiter point, and have adjusted the positions of the Voyager 1 images (all acquired near the limb of Io) to match the best-fit geometry. Horizontal accuracy is nominally 1 pixel, translating to 1 kilometer in low latitude regions with good coverage.
- Completeness Report
The color mosaic has no coverage within ~5° of the north and south poles. The poles are filled in by interpolation in the merged mosaic.
The mosaic is made up of images with mixed resolution, with the poorest coverage on the Jupiter-facing hemisphere. Resolution of this merged mosaic range from 1 to 10 km/pixel.
- Process Date
- 15 March 2009
- Process Description
PDS images were ingested into Integrated Software for Imagers and Spectrometers (ISIS, version 2) and were calibrated using the best end-of-mission calibration information, co-registered to subpixel precision, and map projected using the camera-pointing corrections of Archinal et al. (2001). A Lunar–Lambert limb-darkening correction was next performed, after having first determined that a coefficient of 0.7 was adequate for all three colors. Finally, the images were mosaicked together using a numerical procedure that reduces the mismatch at the seams (Soderblom, L.A., Edwards, K., Eliason, E.M., Sanchez, E.M., and Charette, M.P. 1978. Global color variations on the Martian surface. Icarus 34. doi:10.1016/0019-1035(78)90037-4). The merged mosaic was created by superimposing the color mosaic on the more detailed combined monochrome 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. That is, the red brightness was computed as the product of the monochrome mosaic multiplied by the ratio of the Galileo 756 nm/GRN, and the blue brightness as the monochrome mosaic times the Galileo VIO/GRN ratio.
- Horizontal Positional Accuracy Value
- 1000
- Horizontal Positional Accuracy Report
- Accurate to Control Net
Lineage
- PDS Status
- PDS 3 Like
- Source Originator
- Planetary Data System
- Source Title
- Galileo and Voyager PDS Archives
- Source Online Linkage
- https://pds-imaging.jpl.nasa.gov/volumes/galileo.html#gllSSIREDR, https://pds-imaging.jpl.nasa.gov/volumes/voyager.html#vgrISSEDR-J, http://pds-imaging.jpl.nasa.gov/portal/galileo_mission.html, https://pds-imaging.jpl.nasa.gov/portal/voyager_mission.html
- Type of Source Media
- Online
- Attribute Accuracy Report
- Accurate to Control Net
Geospatial Information
- Minimum Latitude
- -90
- Maximum Latitude
- 90
- Minimum Longitude
- -180
- Maximum Longitude
- 180
- Direct Spatial Reference Method
- Raster
- Object Type
- Pixel
- Lines (pixels)
- 5723
- Samples (pixels)
- 11445
- Bit Type
- 8
- Quad Name
- Radius A
- 1821460
- Radius C
- 1821460
- Bands
- 3
- Pixel Resolution (meters/pixel)
- 1000
- Scale (pixels/degree)
- 31.79
- Horizontal Coordinate System Units
- Meters
- Map Projection Name
- Simple Cylindrical
- Latitude Type
- Planetocentric
- Longitude Direction
- Positive West
- Longitude Domain
- -180 to 180