Planet Four: Terraines is asking for help in mapping the south pole of Mars. For the project, volunteers are asked to identify terrains that are mainly formed by the thawing of carbon dioxide and water ices present in the polar ice cap during the Southern spring and early summer.
The images users review were taken with the Mars Reconnaissance Orbiter Context Imager (CTX). With volunteers’ help, new interesting areas of Mars will be identified to image with HiRISE (High Resolution Imaging Science Experiment), the highest resolution camera ever sent to a planet. With HiRISE, scientists can study these new regions of interest in detail and examine how they change over time.
The images available on Planet Four: Terrains come from the Context Camera (CTX) aboard Mars Reconnaissance Orbiter (MRO). The Context Camera takes wide view images (~30 km x ~60 km) of the Martian surface, providing context for the higher resolution but smaller spatial coverage of MRO’s other instruments.
Scientists have asked for volunteers to participate for a number of reasons.
“Identifying these different terrains is a task that computers are not good at. It turns out that people are really good at this task. Human beings can easily match patterns and identify outliers that can be difficult if not impossible to teach machines to do.”
“Your classifications get stored in the Zooniverse’s database. Later the Planet Four: Terrains science team will combine the multiple volunteer assessments for each image, including your classifications, to identify the terrains present all across the south polar region of Mars.”

A network of 130,000 volunteers is coordinating to map the surface of Mars. Image source: Planet Four.
Scientists are working to identify a number of topographic and geomorphic features from the images, including what they call spiders, baby spiders, channel networks, and Swiss cheese terrain. A new project of mapping ridges is about to get underway.
“With 20 people reviewing each Planet Four: Terrains image, we can accurately determine the features present. By having multiple people independently assess each image, we gain the wisdom of the crowd. It has been shown that the combined assessment of many non-experts can often equal and outperform those of experts and machine learning algorithms.”
Planet Four has evolved from its original inception, which engaged volunteers to help map dark seasonal fans and blotches of Mars’s south pole. More than 130k people are currently involved in the effort.
You can learn more about Planet Four here.