From the USGS press release:
The first topographic map of Mercury was released by the U.S. Geological Survey, Arizona State University, Carnegie Institute of Washington, Johns Hopkins University Applied Physics Laboratory and NASA. This high-resolution map provides the first comprehensive view of Mercury’s entire surface, illustrating the planet’s craters, volcanoes and tectonic landforms. This product brings together observations and scientific findings from NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, which was the first spacecraft to orbit Mercury.
Scientists used data from the MESSENGER spacecraft to produce a highly detailed topographic map, similar to the type of map used by hikers to illustrate elevation changes and landforms. The spacecraft's cameras and sophisticated instruments collected unprecedented images during MESSENGER’s mission, which began in 2011 and included 4,104 orbits around Mercury.