Maps of Io
Ionian Feature Names
Color Map of
Io
1961
Ground based map of Io
In 1961 A. Dollfus and his colleagues at the Pic du Midi observatory in
France produced some preliminary mercator maps of Io, Europa, Ganymede
and Callisto. Although inevitably very rough, these maps at least demonstrate
that a certain amount of surface detail can be seen from Earth using very
large telescopes. The orange colour of Io was also discernible. Since
the Pioneer and Voyager missions, however, it has been possible to produce
far more detailed and accurate maps.
Some of the features that can be seen on this map are Babbar Patera (the
dark, circular spot in the bottom left corner of the map) and Lei-Kung
Fluctus.
This map was provided by John Cody.
Map
of Io using images from Galileo AND Voyager
This map, produced by Jason Perry, uses the best global images taken by
Galileo and Voyager. This map does not reflect Io's current look.
However, in a few areas I chose the best Galileo images even if there
were better Voyager images. I did that for Pele-Pillan and for a
caldera west of Karei Patera that had a plume deposit for much of the
Galileo mission. This map is a rough copy of a map to be produced
later. The areas where Galileo data and Voyager data meet are quite obvious.
In a later release, I hope to fix that.
Galileo-Based Maps
Galileo
Color Map of Io -- 1996-1997
Global Color of Io in an equal-area cylindrical projection. This
mosaic of low phase images from Galileo's second, fourth, sixth, and ninth
orbits is a false-color composite made up of NIR (0.76 µm), green, and
violet filter images. The top frame is linearly contrast-stretched
from 0 to the maximum digital number, and approximates the visual appearance
of Io in 1996-1997. At bottom is an enhanced color representation,
for which each of the NIR, green, and violet filter mosaics have been
stretched individually. (From Geissler et al., 1999)
North
and South Poles of Io
North (left) and south (right) polar projections of Io's color.
(From Geissler et al., 1999)
Galileo Io Base Map, released June 1999, by the USGS. Available
here in various resolutions, all JPEG compressed but with negligible loss
of detail. Documentation,
from Alfred McEwen. 
0.25 degrees/pixel, 1440 x 720 pixels, 214 kbytes.
0.25 degrees/pixel, 1440 x 720 pixels, with lat/lon grid, 220 kbytes.
Original resolution, 2 km/pixel, 5748 x 2874 pixels, 2.0 Mbytes.
Io
map with recent names, in PDF format, at the USGS
Solar System Nomenclature site. UPDATED
The above USGS map in JPEG form. 2954 x 1473 pixels, 1.4 Mbyte image.UPDATED
Galileo image mosaic of Io, with lat/lon grid and names. Not photometric:
good for positions only. From McEwen et al. 1998, Active volcanism on
Io as seen by Galileo SSI, Icarus 135, 181-219. A press
release on the Galileo Web site.
Voyager-Based Maps
Geological Map of Io
Equatorial
Region
North
Polar Region
South
Polar Region
Map
Key
Voyager
1 Color Map
These Voyager-based JPEG-format images have compression artifacts, though
these are very minor. Note: Some of these images are very large-
consider downloading the smaller versions instead.
Voyager image mosaic of Io, using the latest Io control network (accurate
to < 1 degree). Not photometric: good for positions only. Courtesy
Alf
red McEwen. 3600 x 1800 byte array with 0.1 x 0.1 degree pixels, x value
goes from 179.95 to -179.95 degrees longitude, y value from 89.95 to -89.95
degrees in latitude.
Like iobase.jpg but 1800 x 900 with 0.2 x 0.2 degree pixels, from 179.9
to -179.9 in longitude, 89.9 to -89.9 in latitude.
Voyager-era
topographic map of Io.
Global Io topography from Gaskell et al. 1988 (GRL 15, 581), superimposed
on a blue-wavelength Voyager 2 mosaic of Io prepared by Alfred McEwen.
Contour interval 0.5 km, illumination from the upper right. This was an
illustration in the review article by Spencer and Schneider 1996 (Ann.
Rev. Earth. Planet. Sci. 24, 125) but was mostly destroyed by poor image
reproduction.
Documentation
from Alfred McEwen describing the "iobase" mosaic, plus the
above details about the JPEG versions of the mosaics.
Voyager image of Loki, FDS 16389.42, blue filter, reprojected to simple
cylindrical projection and tied to same control net as the iobase mosaic.
Courtesy Alfred McEwen. 848 x 976 byte array with 1/16 degree pixels,
from 275 to 328 in longitude, -11 to +50 in latitude. No photometric corrections
or filtering applied: I/F=DN*0.00294 assuming the narrow-angle blue correction
factor is 1.000.
Voyager 2 global mosaics of Io, by Alfred McEwen.
UV filter mosaic
Violet
filter mosaic
Blue filter mosaic
Green filter mosaic
Orange filter mosaic
Color composite of the above violet, blue, and orange maps.
Global mosaic of Voyager hi-res and med-res images of Io, resampled to
16 pixels per degree or 1.99 km/pixel, size 5760 x 2880 pixels. From Tony
Rosanova at USGS Flagstaff. Longitude range 360 - 0 degrees, latitude
range 90 - -90 degrees.
Global mosaic of lo-res and med-res images of Io, 8 pixels per degree,
Longitude range 180 - -180 degrees, latitude range -90 - 90 degrees. From
Tony Rosanova, USGS Flagstaff
