The science team that oversees the imaging system on board NASA&rsquo;s Lunar  Reconnaissance Orbiter (LRO) has released the highest resolution  near-global topographic map of the moon ever created. This new topographic map, from Arizona State University in Tempe, shows  the surface shape and features over nearly the entire moon with a pixel  scale close to 100 meters (328 feet). A single measure of elevation (one  pixel) is about the size of two football fields placed side-by-side.
Although the moon is our closest neighbor, knowledge of its morphology  is still limited. Due to instrumental limitations of previous missions, a  global map of the moon&rsquo;s topography at high resolution has not existed  until now. With the LRO Wide Angle Camera and the Lunar Orbiter Laser  Altimeter (LOLA) instrument, scientists can now accurately portray the  shape of the entire moon at high resolution. &ldquo;Our new topographic view of the moon provides the dataset that lunar  scientists have waited for since the Apollo era,&rdquo; says Mark Robinson,  Principal Investigator of the Lunar Reconnaissance Orbiter Camera (LROC)  from Arizona State University in Tempe. &ldquo;We can now determine slopes of  all major geologic terrains on the moon at 100 meter scale. Determine  how the crust has deformed, better understand impact crater mechanics,  investigate the nature of volcanic features, and better plan future  robotic and human missions to the moon.&rdquo; Called the Global Lunar DTM 100&amp;#160;m topographic model (GLD100), this map  was created based on data acquired by LRO&rsquo;s WAC, which is part of the  LROC imaging system. The LROC imaging system consists of two Narrow  Angle Cameras (NACs) to provide high-resolution images, and the WAC to  provide 100-meter resolution images in seven color bands over a  57-kilometer (35-mile) swath. The WAC is a relatively small instrument, easily fitting into the palm  of one&rsquo;s hand; however, despite its diminutive size it maps nearly the  entire moon every month. Each month the moon&amp;#8217;s lighting has changed so  the WAC is continuously building up a record of how different rocks  reflect light under different conditions, and adding to the LROC library  of stereo observations.  The LROC (WAC) has a pixel scale of about 75 meters (246 feet), and at  the average altitude of 50&amp;#160;km (31 miles) a WAC image swath is 70&amp;#160;km (43  miles) wide across the ground-track. Since the equatorial distance  between orbits is about 30&amp;#160;km (18 miles) there is complete overlap all  the way around the moon in one month. The orbit-to-orbit WAC overlap  provides a strong stereo effect. Using digital photogrammetric  techniques, a terrain model can be computed from the stereo overlap.  The near-global topographic map was constructed from 69,000 WAC stereo  models and covers the latitude range 79&deg;S to 79&deg;N, 98.2% of the entire  lunar surface. Due to persistent shadows near the poles it is not  possible to create a complete stereo based map at the highest latitudes.  However, another instrument onboard LRO called LOLA excels at mapping  topography at the poles. Since LOLA ranges to the surface with its own  lasers, and the LRO orbits converge at the poles, a very high resolution  topographic model is possible, and can be used to fill in the WAC &ldquo;hole  at the pole.&rdquo; The WAC topography was produced by LROC team members at  the German Aerospace Center. &ldquo;Collecting the data and creating the new topographic map was a huge  collaborative effort between the LRO project, the LOLA team, the LROC  team at ASU and in Germany at the DLR,&rdquo; says Robinson. &ldquo;I could not be  more pleased with the quality of the map &ndash; it&rsquo;s phenomenal! The richness  of detail should inspire lunar geologists around the world for years to  come.&rdquo; Shaded relief images can be created from the GLD100 by illuminating the  &ldquo;surface&rdquo; (in this case the shape model) from a given Sun direction and  elevation above the horizon. To convey an absolute sense of height the  resulting grayscale pixels are painted with colors that represent the  altitude. Visualizations like these allow scientists to view the surface  from very different perspectives, providing a powerful tool for  interpreting the geologic processes that have shaped the moon. The LRO spacecraft is managed by NASA&amp;#8217;s Goddard Space Flight Center in  Greenbelt, Md., for NASA&amp;#8217;s Science Mission Directorate in Washington.Future versions The current model incorporates the first year of stereo imaging; there  is another year of data that can be added to the solution. These  additional stereo images will not only improve the sharpness  (resolution) of the model but also fill in very small gaps that exist in  the current map. Also the LROC team has made small improvements to the  camera distortion model and the LOLA team has improved our knowledge of  the spacecraft position over time. These next generation steps will  further improve the accuracy of the next version of the LROC GLD100  topographic model of the moon.&rsaquo; Related story and imagery from Arizona State University