The WAC Digital Terrain Model (DTM; or Global Lunar DTM 100 meter topographic model "GLD100") was derived from WAC observations, and covers 98.2% of the lunar surface. Using digital photogrammetric techniques, the GLD100 was computed from 69,000 WAC stereo models. Due to persistent shadows near the poles it is not possible to create a complete WAC stereo map at the very highest latitudes. The GLD100 thus covers from 79 degrees S latitude to 79 degrees N latitude. Since the stereo correlation box is bigger than 100 meters, surface details at the 100-meter scale are not fully resolved. However, each 100-meter square has an average of 26 stereo points within it (for a planet-wide total of 100 billion points), which helps to sharpen the elevation estimate. The resolution, in a formal sense, is probably close to 300 meters, and the accuracy of the elevations is estimated to be about 10 to 20 meters. The GLD100 is available in the original 100 meters/pixel scale format in ten tiles. The GLD100 is also available in tile format for scales of 256 pixels per degree (ppd) and 128 ppd. At lower resolutions (64 ppd, 32 ppd, 16 ppd, 8 ppd, and 4 ppd), there is a Simple Cylindrical product covering the entire lunar surface from 0 to 360 degrees longitude at each resolution. The LRO Lunar Orbiter Laser Altimeter (LOLA) excels at characterizing the topography of the poles. Since the LRO orbits converge at the poles, LOLA provides a higher resolution topographic model at the poles. For all products except the 100 meter/pixel tiles, the LOLA polar data fills in the WAC "hole at the pole". The extents of the tiles vary by pixel scale. For the 100 meters/pixel and 256 ppd scales, there are eight quadrangles covering -60 to 60 degrees latitude (equatorial region) and increments of 90 degrees of longitude, projected in the Equirectangular projection. For the GLD100 at 128 ppd, there are eight quadrangles covering -90 to 90 degrees latitude in Equirectangular projection. For all three pixel scales, there are Polar Stereographic maps covering 60 - 90 degrees latitude. Each file is named with the following pattern (see Table 1 for examples): WAC_GLD100_[E|P]###[N|S]????_***[M|P] where: [E|P] indicates the map projection (E=Equirectangular or P=Polar Stereographic) ###[N|S] indicates the center latitude in 1/10th degrees North (N) or South (S) ???? indicates the center longitude in 1/10th degrees East ***[M|P] indicates the scale in meters/pixel (M) or pixels/degree (P) Low-resolution 8-bit browse products in PNG format for this product, along with full-resolution 8-bit GeoTIFFs, are available at the following location, with names matching those of the full-resolution IMG files: http://lroc.sese.asu.edu/data/LRO-L-LROC-5-RDR-V1.0/LROLRC_2001/EXTRAS/BROWSE/WAC_GLD100/ Table 1: Parameters of representative WAC_GLD100 tiles. Product Name Latitude Range Longitude Range Resolution WAC_GLD100_E300N0450_100M 0° - 60° 0° - 90°E 100 mpp WAC_GLD100_E300N0450_256P 0° - 60° 0° - 90°E 256 ppd WAC_GLD100_E450N2250_128P 0° - 90° 180° - 270°E 128 ppd WAC_GLD100_P900N0000_128P 60° - 90° 0° - 360°E 128 ppd WAC_GLD100_E000N1800_064P -90° - 90° 0° - 360°E 64 ppd WAC_GLD100_E000N1800_032P -90° - 90° 0° - 360°E 32 ppd WAC_GLD100_E000N1800_016P -90° - 90° 0° - 360°E 16 ppd WAC_GLD100_E000N1800_008P -90° - 90° 0° - 360°E 8 ppd WAC_GLD100_E000N1800_004P -90° - 90° 0° - 360°E 4 ppd The WAC topography was produced by LROC team members at the German Aerospace Center (DLR; http://www.dlr.de/). When citing this product, use the following reference: Scholten, F., Oberst, J., Matz, K. D., Roatsch, T., Wählisch, M., Speyerer, E. J., & Robinson, M. S. (2012). GLD100: The near-global lunar 100 m raster DTM from LROC WAC stereo image data. Journal of Geophysical Research: Planets, 117(E12). https://dx.doi.org/10.1029/2011JE003926 If using data poleward of 79 degrees, also use this reference: Smith, D. E., Zuber, M. T., Neumann, G. A., Lemoine, F. G., Mazarico, E., Torrence, M. H., McGarrey, J. F., Rowlands, D. D., Head, J. W., Duxbury, T. H., Aharonson, O., Lucey, P. G., Robinson, M. S., Barnouin, O. S., Cavanaugh, J. F., Sun, X., Liiva, P., Mao, D., Smith, J.C., & Bartels, A. E. (2010). Initial observations from the lunar orbiter laser altimeter (LOLA). Geophysical Research Letters, 37(18). https://dx.doi.org/10.1029/2010GL043751 For more information on LROC Reduced Data Records (RDRs), please refer to the Software Interface Specification (SIS): http://lroc.sese.asu.edu/data/LRO-L-LROC-5-RDR-V1.0/LROLRC_2001/DOCUMENT/RDRSIS.PDF