There are various Mars Atlases available on the Internet, and we do not claim that this feature on our site is an original one. We do hope that, with these simple directions, it is easier to use and more user-friendly than most.
Lines of latitude refer to being north or south of the equator; in all of our maps, north is up. Longitude refer to being east or west; as you browse around the map, you will see that longitude "wraps around" and changes from west to east or east to west at zero degrees and at 180 degrees. We have chosen to use images from a sinusoidal projection--meaning that the map curve up near the poles rather than spreading those areas out to make a rectangular map. For each of the northern and southern hemispheres, you will be asked to pick one of four quadrants in which to browse; as you look at these, you can keep in mind that they curve to a point at the top because of this method of portraying them.
Scale. Since we wanted to make the maps fast-loading, each close-up image shows Mars in 1/16th resolution, which means that it takes 16 pixels (dots in the picture) to travel along one degree of latitude or longitude. With this particular map, this means that each pixel represents about two and a half miles (four kilometers) each way of Martian surface.
There are various ways to move through our Mars Map:
first choose a hemisphere to explore; you will be taken to a view of its four quadrants
then pick a quadrant; you will be taken to a page showing the small sections that make it up
select one of these sections by clicking on it and you'll be on the surface
On the surface, viewing these small sections, you can use:
arrow buttons to move around on the surface
text links to go back to a particular quadrant or hemisphere
the pull-down menu of landing sites that are possibilities for the mission simulation (this will work even if you are not a logged-in user designing a mission)
The images used to assemble the map are taken from compact discs filled with grayscale images from the Viking orbiter space probes; these discs were assembled by NASA. Also, access to reading software that students used to display and save the images was provided by Dr. Sanjay Limaye of the University of Wisconsin. The images were cropped, colorized (done in shades of orange) and manipulated by the students working on this project; the images and HTML pages were organized using programs that they wrote.
Mission to Mars. An educational site created for the ThinkQuest contest.