CGI Moon Kit

Within 3D animation software, an object like the Moon begins as a simple geometric shape, in this case a sphere. Texture maps like the ones on this page are used to add detail to the model. The color map tells the software how to paint the surface, and the displacement map tells it how to add the shape details that define the lunar terrain. Without them, the Moon model is just a smooth, monochrome ball. Although these maps are flat rectangles, the software understands them as maps of a spherical surface and knows how to warp them onto spherical geometry.

Each pixel in these texture maps corresponds to a point on the lunar surface defined by a longitude-latitude pair. Pixels in the color map contain the base color of the surface, before applying the effects of varying light and camera angles (called incidence angle i and emission angle e in the technical description). Pixels in the displacement map contain the height of the surface at the corresponding locations.

More Data

These maps are a tiny subset of the data publicly archived by the LRO instrument teams. All of the data is in standard and fairly simple PDS file formats (files with .IMG filename extensions). Although not typically supported by general-purpose computer graphics software, these formats are directly readable by some GIS programs. The data formats are documented in PDS labels, which are either separate text files with a .LBL filename extension or embedded as fixed-length headers. Other than the possible header, most .IMG files are uncompressed 2D binary arrays of numbers. Some data is also available in TIFF or JPEG2000 formats.

As of this writing, the best global-scale elevation data for equatorial and mid-latitude regions of the Moon, at resolutions up to 512 pixels per degree, is SLDEM2015. For regions near the poles, where the density of laser shots is much higher, the GDR data in polar stereo projection reaches resolutions of five meters per pixel.

The LROC narrow-angle camera (NAC) has imaged most of the Moon's surface at a resolution of one meter per pixel or better. LROC imagery can be explored graphically using its Quickmap interface and searched on its RDR Product Select page. Of particular interest are the Topographic Products (menu option in the upper left of the page), which are matched with high-resolution DEMs derived from stereo image pairs. This dataset includes all of the Apollo landing sites and dozens of other locations of interest.