Various implementations described herein are directed to generating a map using radar data. In one implementation, a non-transitory computer-readable medium may have stored thereon a plurality of computer-executable instructions which, when executed by a computer, cause the computer to receive radar data for a marine environment proximate to a vessel, where the radar data are received from a radar sensor disposed on or proximate to the vessel. The computer-executable instructions may further be configured to cause the computer to generate a map of one or more substantially stationary objects in the marine environment based on the radar data.