International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B4, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
meter sampling square has an average of 26 stereo points (from 
multiple months observations; for a planet-wide total of 100 
billion points), which sharpens the elevation estimate at that 
scale. The resolution, in a formal sense, is probably close to 300 
meters globally, and the vertical accuracy of the elevations is 
estimated to be better than 20 meters [Scholten et al., 2012]. 
The GLD100 is archived in the original 100 meter pixel scale 
format in ten tiles (identical to that of the WAC mosaic, see 
table 1). The GLD100 is also available in same tile format for 
scales of 256 ppd and 128 ppd. Since the LRO orbits converge 
at the poles, Lunar Orbiter Laser Altimeter (LOLA) provides a 
very high resolution topographic model of the poles [Smith et al 
2010a,b, Zuber et al, 2010]. For the 256 ppd and lower 
resolution formats the LOLA polar data fills in the WAC "hole 
at the pole", above and below 79°N and 79°S, respectively. 
Shaded relief images were created from the GLD100 by 
illuminating the surface from a given Sun direction and 
elevation above the horizon (Figure 2). To convey an absolute 
sense of height, the resulting shaded relief grayscale pixels were 
painted with colors that represent the elevation (relative to the 
mean lunar radius). The GLD100 Color Shaded Relief map is 
available at 128 ppd in the same tiled format as the GLD100, as 
well as global files at lesser resolutions. All of the Color Shaded 
Relief products are available with and without latitude and 
longitude grids (10° increments). 
2.3 WAC Polar Movies 
During overpasses of the north and south pole, the WAC images 
the terrain from 80° poleward to 90° and back to 80° on the 
night side. With the 90° field of view (in monochrome mode), 
the WAC provides images with repeat spatial coverage around 
both lunar poles, which enable the visualization lighting 
conditions as the Sun progresses across the horizon each lunar 
day and the sub-solar latitude migrates from 1.5° S to 1.5° N 
over a lunar year. This small tilt in the spin axis leaves some 
areas near the poles in permanent shadow, while other nearby 
regions remain sunlit for the majority of the year. Theory, radar 
observations, neutron measurements, and Lunar CRater 
Observation and Sensing Satellite (LCROSS) experiments 
suggest that volatiles may be present in cold traps in 
permanently shadowed regions. While, areas of near permanent 
illumination are prime locations for future lunar outposts due to 
their benign thermal conditions and near constant accessibility 
to solar power. 
One of the primary scientific objectives of the Lunar 
Reconnaissance Orbiter Camera (LROC) is to unambiguously 
identify regions of permanent shadow and near permanent 
illumination using its two imaging systems that provide medium 
and high resolution views of the poles. Since the start of the 
nominal mission, LROC has acquired over 20,000 Wide Angle 
Camera (WAC) images of the polar regions. LRO's 50-km polar 
orbit enables images of each pole to be acquired every ~2 hours 
during normal spacecraft and instrument operations (average 
time between WAC observations is 2.3 hours including 
spacecraft and instrument disturbances). The WAC 90° field of 
view (monochrome mode) allows for a 104-km region within 2° 
degrees of the pole to be acquired at a pixel scale of 100 m. This 
mulitemporal coverage delimits permanently shadowed regions 
and permanently (or near permanently) illuminated regions over 
full year (2/16/2010 to 2/16/2011) with time steps every 2.3 hrs 
(on average) [Speyerer, et al. 2012a]. The polar images were 
map projected on the LOLA shape model produced in 
December 2010 with LOLA derived crossover corrected 
ephemeris (when available) and an improved camera-pointing 
model to provide accurate geospatial positioning [Zuber et al., 
2010; Mazarico et al, 2012]. As the Moon rotates, LRO's 
orbital inclination changes slightly, which causes the WAC 
frames to wander across the poles over time thus slightly 
reducing the area of complete repeat coverage. 
2.4 NAC Polar Mosaics 
Due to the tilt of the lunar spin axis noticeable lighting changes 
occur from lunation to lunation. The polar regions are most 
illuminated at their respective summer solstice. Thus, a 
mosaicking campaign was executed for each pole centered on 
the respective summer solstice (2010-07-23 through 2010-12-11 
for the south pole and 2010-1-18 through 2010-6-7 for the north 
pole). The mosaic has a latitude range of -90° to - 85.5° latitude 
and is stored as 24 polar stereographic map tiles. The tiles are in 
latitudinal bands radiating from the pole. There are four tiles in 
the first band (90° to 88.5° latitude), eight in the second (88.5° 
to 87° latitude) and twelve in the third (87° to 85.5° latitude) at 
each pole (N,S). 
NAC images were map projected onto the LOLA polar 5 
m/pixel DEM using the LOLA crossover corrected ephemeris at 
a pixel scale of 2 m [Smith et al., 2010; Mazarico et al., 2012]. 
The images were not registered to one another, and the mapping 
error between images is on average 7.2 meters in the sample 
direction and 4.6 meters in the line direction. 
2.5 NAC Regional Mosaics 
The two Narrow Angle Cameras (NACs) provide high- 
resolution (0.5 to 2.0 m/pixel) panchromatic images over a 
combined 5 km swath across track and 25 km down track. 
Images acquired over many orbits and multiple months can be 
mosaicked to create local area maps. NAC images acquired 
under similar lighting conditions (e.g. high sun/low sun) were 
map-projected using the GLD100 (WAC derived 100 m/pixel 
DEM) and LOLA derived crossover corrected ephemeris 
[Scholten et al., 2012; Mazarico et al., 2012]. In some cases 
images with similar incidence angles have opposite solar 
azimuth angles (east and west). A local semi-controlled network 
was then generated to align images into large mosaics of the 
region. Due to the large size of the NAC mosaics, the pyramidal 
tiffs were down-sampled by approximately a factor of 4 to 
2m/px or 8m/px. 
2.6 NAC DEM 
LROC NAC DEMs are made from geometric stereo pairs (two 
images of the same area on the ground, taken from different 
view angles under nearly the same illumination) [Tran et al., 
2010; Burns et al., 2012]. LROC was not designed as a stereo 
system, but can obtain stereo pairs through images acquired 
from two orbits (with at least one off-nadir slew). Off-nadir 
rolls interfere with the data collection of the other instruments, 
so LROC slew opportunities are limited to four per day. Due to 
the time-intensive process, not all of the stereo pairs have been 
made into DEMs. 
To generate a DEM, we use a combination of the USGS 
Integrated Software for Imagers and Spectrometers (ISIS) and 
SOCET SET from BAE Systems. ISIS routines ingest the image 
files, perform a radiometric correction, and export to a format 
SOCET SET accepts. The files imported into SOCET SET are 
Level 1 radiometrically corrected NAC images and a list of 
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