–6000

–5000

–6000

–6000

–5000

–6000

–5000

–6000

–5000

–6000

–6000

–6000

–5000

–6000

–5000

280°W

279°W

278°W

277°W

276°W

275°W

280°W

279°W

278°W

277°W

275°W

276°W

–42°

–42°

–41°

–40°

–39°

–38°

–41°

–40°

–39°

–38° 80°E

–37.5°

81°E

82°E

83°E

84°E

85°E

80°E

81°E

82°E

83°E

85°E

84°E

–42.5°

–42°

–41°

–40°

–39°

–38°

–37.5°

–42.5°

–42°

–41°

–40°

–39°

–38°

Dao Val lis

HELLAS

PLANITIA

Photogrammetry by M.R. Rosiek

Map compilation by M.R. Rosiek and B.L. Redding

Digital terrain model review by B.L. Redding and D.M. Galuszka

Nomenclature by J.S. Blue

Technical review by D. Crown and E. Howington-Kraus

Editing by J.L. Zigler

Cartography by D.A. Ryan

Manuscript approved for publication May 31, 2006

Prepared on behalf of the Planetary Geology and Geophysics 

Program, Solar System Exploration Division, Office of Space 

Science, National Aeronautics and Space Administration.

SCIENTIFIC INVESTIGATIONS MAP 2926

–4,500

–4,750

–5,000

–5,250

–5,500

–5,750

–6,000

–6,250

–6,500

–6,750

–7,000

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.

MTM 500k –40/082E OMKT

The map code identifies the Mars topographic maps:

MTM 500k –40/082E OMKT: Mars transverse Mercator projection 

(MTM); 1:500,000 series; center of sheet lat 40° S., long 82.5° E. in 

planetocentric coordinate system (this corresponds to –40/277; lat 40° S., 

long 277.5° W. in planetographic coordinate system); orthophotomosaic 

(OM) with color-coded (K) topographic contours and nomenclature (T) 

(Greeley and Batson, 1990)

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 3,396.19 km 

and a polar radius of 3,376.2 km (Seidelmann and others, 2002). 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, 2002).

PROJECTION

The projection is part of a Mars transverse Mercator (MTM) system with 

20°-wide zones. For the area covered by this map, the central meridian is at 

90° E. (270° 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 (black) as allowed 

by International Astronomical Union/International Association of Geodesy 

(IAU/IAG) standards (Seidelmann and others, 2002) and in accordance with 

current National Aeronautics and Space Administration (NASA) and U.S. 

Geological Survey (USGS) standards (Duxbury and others, 2002). A secondary grid (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 map 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 stereomodels based on orbit 406, 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 85 m to 

105 m with a mean of 95 m. For stereomodels based on orbits 329 and 363, 

the local expected vertical precision ranges from 115 m to 130 m with a mean 

of 122 m. Elevation (in meters) is given with respect to the adopted Mars 

topographic datum (see section named "Adopted Figure"). A comparison of 

the DTM with the MOLA grid shows that the DTM is on average 6.2 m lower 

than the MOLA points (n=202,078; μ=–6.2 m; σ=45.5 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 most of the DTM is 600 m; features that are less than 600 m in 

diameter will not be resolved, and features that are smaller than 1,800 m in 

diameter 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 406 

and 363. 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 map are approved by the IAU. For a complete list of IAUapproved names, see the Gazetteer of Planetary Nomenclature at 

http://planetarynames.wr.usgs.gov.

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, 

Commission IV, Working Group 9—Extraterrestrial Mapping, Ottawa, 

Canada, 2002, 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.O., Grecu, A.E., and Castro, 

S.K., 2000, MDIM 2.0—A revised global digital image mosaic of Mars in

Lunar and Planetary Science XXXI: Houston, Texas, 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, American Society for Photogrammetry 

and Remote Sensing, 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.J., 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 Becker, K.J., 1997, ISIS—A software architecture for 

processing planetary images [abs.], in Lunar and Planetary Science 

Conference XXVIII: Houston, Texas, Lunar and Planetary Institute, p. 

1443.

Topographic Map of the Western Region of Dao Vallis in Hellas Planitia, Mars

MTM 500k –40/082E OMKT

By

Mark R. Rosiek, Bonnie L. Redding, and Donna M. Galuszka

2006

CONTOUR GUIDE (meters)

10 20 30 40 50 60 80 90 70 100 KILOMETERS

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

TRANSVERSE MERCATOR PROJECTION

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

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Prepared for the

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

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.

Available at http://pubs.usgs.gov/sim/2006/2926

Diagram of map area showing locations of stereo-image pairs used to produce the 

topographic information. Numbers on the diagram correspond to numbered stereo-image 

pairs listed below. Shaded area indicates MOLA data.

 No. IMAGE PAIR No. IMAGE PAIR No. IMAGE PAIR

 1 406S40/406S18 9 363S46/329S10 17 406S48/406S25

 2 363S48/329S11 10 363S44/329S07 18 406S46/406S23

 3 363S48/329S12 11 406S44/406S20 19 406S44/406S21

 4 363S46/329S09 12 406S44/406S22 20 406S42/406S19

 5 406S42/406S20 13 406S46/406S22 21 406S43/406S21

 6 363S27/329S12 14 363S44/329S08 22 406S41/406S19

 7 363S27/329S10 15 406S46/406S24 23 406S45/406S21

 8 363S25/329S08 16 406S48/406S24 24 406S47/406S23

MTM –40/082E QUADRANGLE VIKING STEREOMODEL COVERAGE

EAST

WEST

NORTH

MC–21

MC–5

MC–6

MC–7

MC–12 MC–13 MC–14 MC–15

MC–1

MC–20 MC–22 MC–23

MC–27

MC–28

MC–29

MC–30

60°

60° 120°

120°

0°

30°

65°

360° 45° 90° 135°

180°

–30°

–65°

0°

30°

65°

–30°

–65°

QUADRANGLE LOCATION

Photomosaic showing location of map area. An outline of 

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

1

4

4

4

2 3

5

8

7

6

10

9

14

11

12

13

15 16

17

18

19

20

21

22

23

24

SOUTH