This digital elevation map, produced from satellite data overlain on an image taken by the Mars Orbital Camera on NASA's Mars Global Surveyor spacecraft, shows changes in elevation along the trek of NASA's Mars Exploration Rover Spirit as of the rover's 328th martian day, or sol (Dec. 4, 2004). To that point, Spirit had driven a total of 3.89 kilometers (2.42 miles).
The blue area represents the basaltic plains on the floor of Gusev Crater, about 20 meters (66 feet) below the rover's present location. Spirit crossed those plains for several months after landing to the west, off the left edge of this image. The greenish-blue area is the "West Spur" of the "Columbia Hills," which Spirit reached on sol 156 (June 11, 2004). Since then, Spirit has been gradually ascending the slopes of the "West Spur" in an east-northeasterly direction. Southeast of the rover's current position is a brighter green area that represents an abrupt increase in slope where the "West Spur" meets the steeper flanks of the "Columbia Hills." The yellow and red areas represent the highest slopes and peaks. A steep valley east of the rover's location appears, from orbiter images, to have layered outcrops. Scientists are directing the rover to a ridge overlooking the valley to get a better look at what lies ahead.