85°W

–3°

–4°

–5°

–6°

–7°

85°W 84°W 83°W

81°W

80°W

–7°

–6°

–5°

–4°

–3°

81°W 80°W

84°W 83°W 82°W

82°W

MC–17

MC–2

MC–3

MC–4

MC–8 MC–9 MC–10 MC–11

MC–1

MC–16 MC–18 MC–19

MC–24

MC–25

MC–26

MC–30

120°

120° 60°

60°

30°

65°

180° 135° 90° 45° 0°

–30°

–65°

30°

65°

–30°

–65°

–2.5°

275°E

–3°

–4°

–5°

–6°

–7°

–7.5°

275°E 276°E 277°E

278°E

279°E

280°E

–7.5°

–7°

–6°

–5°

–4°

–3°

–2.5°

279°E 280°E

277°E 278°E 276°E

–1000

–4000

3000

4000

4000

4000

–3000

–3000

0

–2000

0

2000

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–3000

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1000

–1000

0

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TITHONIUM 

CHASMA

Tithoniae

Fossae

Tithoniae 

Catenae

Tithoniae 

Fos sae

IUS 

CHASMA

Geryon Montes

NOTES ON BASE

This map, compiled photogrammetrically from Viking Orbiter stereo image pairs, 

is part of a series of topographic maps of areas of special scientific interest on 

Mars.

ADOPTED FIGURE

The figure of Mars used for the computation of the map projection is an oblate 

spheroid (flattening of 1/176.875) with an equatorial radius of 3396.0 km and a 

polar radius of 3376.8 km (Kirk and others, 2000). The datum (the 0-km contour 

line) for elevations is defined as the equipotential surface (gravitational plus rotational) whose average value at the equator is equal to the mean radius as determined by Mars Orbiter Laser Altimeter (MOLA; Smith and others, 2001).

PROJECTION

The projection is part of a Mars Transverse Mercator (MTM) system with 20° wide 

zones. For the area covered by this map sheet the central meridian is at 270° E. (70° 

W.). The scale factor at the central meridian of the zone containing this quadrangle 

is 0.9960 relative to a nominal scale of 1:500,000.

COORDINATE SYSTEM

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 been used for previous Mars maps.

CONTROL

Horizontal and vertical control was established using the Mosaicked Digital Image 

Model 2.0 (MDIM 2.0; Kirk and others, 2000) and MOLA data. A portion of 

MDIM 2.0 covering the mapping area was extracted in simple cylindrical projection. This MDIM image was georeferenced to the MOLA data with an affine transformation. The MDIM image and georeferencing information were imported into a 

digital photogrammetric workstation (Miller and Walker, 1993) and used as an 

orthophoto to provide horizontal control to stereopairs of Viking imagery. The horizontal information was used to extract vertical control from the MOLA data. Note 

that the distribution of Viking Orbiter images suitable for mapping at a scale of 

1:500,000 is uneven. Areas mapped in this series are chosen, often in blocks of two 

or more adjacent quadrangles, based on scientific interest as well as on the availability of suitable data for accurate mapping.

CONTOURS

Contours were derived from a digital terrain model (DTM) compiled on a digital 

photogrammetric workstation using Viking Orbiter stereo image pairs with orientation parameters derived from an analytic aerotriangulation. Contours were drawn 

automatically using a commercial geographic information system (GIS) software 

package (Environmental Systems Research Institute, 1994). For the stereomodels, 

the local expected vertical precision, based on image resolutions, parallax-to-height 

ratio (that is, convergence angle), and a matching accuracy of 0.2 pixel ranges from 

42 m to 403 m, with a mean of 83 m. Elevation (in meters) is given with respect to 

the adopted Mars topographic datum (see "Adopted Figure" section). A comparison 

of the DTM values at the MOLA point locations shows that the DTM is on average 

7 meters higher than the MOLA points (n=248,951; μ=7 m; σ=152 m). Contour 

lines were generated automatically using GIS software and were not edited. 

Because the contour lines were not edited, small closed contour lines, contour lines 

that intersect, and contour lines that do not match features are present. The post 

spacing for the DTM is 600 m; features that are less than 600 m in size will not be 

resolved and features that are smaller than 1800 m in size may only have four elevation measurements associated with them. This lack of elevation measurements 

may result in contour lines that do not adequately represent some features. The purpose of this mapping project is to produce the digital orthophoto and DTM. This 

map provides a graphical representation of the digital products that are available.

IMAGE BASE

The image base for this map employs Viking Orbiter images from orbits 682, 608, 

912, and 334. An orthophotomosaic was created on the digital photogrammetric 

workstation using the DTM compiled from stereo models. Integrated Software for 

Imagers and Spectrometers (ISIS; Torson and Becker, 1997) provided the software 

to project the orthophotomosaic into the Transverse Mercator Projection.

NOMENCLATURE

Names on this sheet are approved by the International Astronomical Union (IAU). 

For a complete list of IAU approved names, see the Gazeteer of Planetary Nomenclature at http://planetarynames.wr.usgs.gov.

MTM 500k –05/277E OMKT: Abbreviation for Mars Transverse Mercator; 

1:500,000 series; center of sheet latitude 5° S., longitude 277.5° E. in 

planetocentric coordinate system (this corresponds to –05/082; latitude 5° 

S., longitude 82.5° W. in planetographic coordinate system); orthophotomosaic (OM) with color-coded (K) topographic contours and nomenclature (T) [Greeley and Batson, 1990]

REFERENCES

Duxbury, T.C., Kirk, R.L., Archinal, B.A., and Neumann, G.A., 2002, Mars Geodesy/Cartography Working Group Recommendations on Mars Cartographic 

Constants and Coordinate Systems, in Joint International Symposium on Geospatial Theory, Processing and Applications, Ottawa, Canada, 2002, Commission IV, Working Group 9—Extraterrestrial Mapping, Proceedings: Ottawa, 

Canada, International Society for Photogrammetry and Remote Sensing 

[http://www.isprs.org/commission4/proceedings/ paper.html].

Environmental Systems Research Institute, 1994, Arc commands: Redlands Calif., 

Environmental Systems Research Institute, Inc.

Greeley, Ronald, and Batson, R.M., 1990, Planetary mapping: New York, Cambridge University Press, p. 261–276.

Kirk, R.L., Lee, E.M., Sucharski, R.M., Richie, J., Grecu, A., and Castro, S.K., 

2000, MDIM 2.0: A revised global digital image mosaic of Mars in Lunar and 

Planetary Science XXXI:Houston, Lunar and Planetary Institute, abstract 2011 

[CD–ROM].

Miller, S.B., and Walker, A.S., 1993, Further developments of Leica Digital Photogrammetric Systems by Helava, ACSM/ASPRS Annual Convention and 

Exposition, Technical Papers, v. 3, p. 256–263.

Seidelmann, P.K. (chair), Abalakin, V.K., Bursa, M., Davies, M.E., De Bergh, C., 

Lieske, J.H., Oberst, J., Simon, J.L., Standish, E.M., Stooke, P., and Thomas, 

P.C., 2002, Report of the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites: 2000: Celestial 

Mechanics and Dynamical Astronomy, v. 82, p. 83–110.

Smith, D.E., Zuber, M.T., Frey, H.V., Garvin, J.B., Head, J.W., Muhleman, D.O., 

Pettengill, G.H., Phillips, R.J., Solomon, S.C., Zwally, H.J., Banerdt, W.B., 

Duxbury, T.C., Golombek, M.P., Lemoine, F.G., Neumann, G.A., Rowlands, 

D.D., Aharonson, O., Ford, P.G., Ivanov, A.B., McGovern, P.J., Abshire, J.B., 

Afzal, R.S., and Sun, X., 2001, Mars Orbiter Laser Altimeter (MOLA)–Experiment summary after the first year of global mapping of Mars: 

Journal of Geophysical Research, v. 106, p. 23,689–23,722.

Torson, J.M., and K.J., Becker, 1997, ISIS—A software architecture for processing 

planetary images (abs.), in Lunar and Planetary Science Conference XXVIII: 

Houston, Lunar and Planetary Institute, p. 1443.

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

GEOLOGIC INVESTIGATIONS SERIES I–2806

Version 1.0

Prepared for the

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

NORTH

SOUTH

WEST

EAST

Prepared on behalf of the Planetary Geology and Geophysics Program, Solar System Exploration Division, Office of Space Science, 

National Aeronautics and Space Administration.

Manuscript approved for publication August 14, 2003

SCALE 1:502 000 (1 mm = 502 m) AT 270° E. (90° W.) LONGITUDE

TRANSVERSE MERCATOR PROJECTION

10 20 30 40 60 80 90 70 100

KILOMETERS

CONTOUR INTERVAL 250 METERS

Planetocentric latitude and east longitude coordinate system shown in black.

Planetographic latitude and west longitude coordinate system shown in red.

10

4113 5758

648334

6457

5759

4112

6358 6558

5964

6559

6558

6558

The following is a list of image pairs used to produce the topographic information 

for this map. Numbers below correspond to the numbers on the diagram above.

 ID IMAGE PAIR ID IMAGE PAIR ID IMAGE PAIR

6559 065A12–059A22 065A11–059A22 059A25–064A27

 065A22–059A25 065A11–059A20 059A25–064A25

 065A20–059A25 065A10–059A20 059A24–064A27

 065A19–059A25 648334 648A10–334S44 059A24–064A26

 065A19–059A23 6558 065A21–058A73 059A24–064A25

 065A18–059A25 065A19–058A73 059A24–064A24

 065A18–059A24 065A13–058A71 059A24–064A23

 065A18–059A23 065A12–058A72 059A22–064A21

 065A17–059A23 065A11–058A74 5758 057A47–058A67

 065A16–059A24 6457 064A26–057A47 057A45–058A70

 065A16–059A23 064A24–057A45 057A43–058A70

 065A16–059A22 064A21–057A45 5759 057A43–059A22

 065A15–059A23 6358 063A44–058A73 057A43–059A20

 065A15–059A21 063A42–058A75 057A41–059A20

 065A14–059A22 063A42–058A73 4112 041A30–012A13

 065A13–059A21 063A40–058A76 4113 041A20–013A13

 065A13–059A20 5964 059A26–064A27

 065A12–059A20 059A26–064A26

MTM –05/277E QUADRANGLE VIKING STEREOMODEL COVERAGE

QUADRANGLE LOCATION

Photomosaic showing location of map area. An outline of 

1:5,000,000-scale quadrangles is provided for reference.

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Dimensional calibration may vary between electronic plotters and between X and Y 

directions on the same plotter, and paper may change size due to atmospheric conditions; therefore, scale and proportions may not be true on plots of this map.

Digital files available on World Wide Web at http://pubs.usgs.gov/imap/i2806

Topographic Map of the Tithonium Chasma Region of Mars

MTM 500k –05/277E OMKT

By

U.S. Geological Survey

2004

5250

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1500 

1250 

1000 

750

500 

250 

0 

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–5250

Contour Guide, in meters