NASA’s Planetary Geology, Geophysics and Geochemistry Laboratory

Goddard Space Flight Center

Slope and Azimuth from SLDEM2015

Erwan Mazarico

The SLDEM2015 data product (Barker et al., 2016) is a combination of the geodetically-accurate, high-precision LOLA altimetric profiles with the high-resolution raster tiles derived from the stereo Kaguya Terrain Camera images (Haruyama et al, 2012). Its true resolution is near 512 pixels per degree (ppd), equivalent to 60 meters per pixel near the equator, and better at higher latitudes.

We used this shape dataset to derive global maps of maximum slope and slope azimuth. While not containing additional information intrinsically, they tend to highlight other metrics of the lunar surface topography.
While the available SLDEM2015 product covers the +/-60 degrees latitude band (>86% of the lunar surface area), these slope and azimuth maps are truly global (pole to pole). These slope and azimuth maps are available at various resolutions: 64 ppd, 128 ppd, 256 ppd, and 512 ppd. Importantly, these also correspond to the spatial baseline associated with the slopes and azimuths. That is, one should not expect similar values of slope in the 64 ppd and 512 ppd maps, as the spatial baselines of these differ by a factor of 8. Given the fractal nature of the lunar surface (Rosenburg et al., 2011), the shorter-baseline slopes are typically larger.

Samples


Here are some sample images created from the SLDEM2015 shape, slope, and azimuth maps. Click on them for higher resolution.



Global map.



Mare Orientale.



Mare Serenitatis.


Data Availability


The SLDEM2015 slope and azimuth dataset is available on the LOLA PDS node at:

http://imbrium.mit.edu/DATA/SLDEM2015_SLOPE/

Global maps (i.e., a single file each) are available at 64, 128, and 256 ppd in the FLOAT_IMG and GeoJPEG2000 formats.

The highest resolutions are available as tiled maps: 12 segments for the 256 ppd product, and 48 segments for the 512 ppd product.

Please carefully read the product labels (LBL files).


Citation

Please cite the Barker et al. (2016) reference below if you use these products in your scientific work.


References

Barker, M.K. et al., 2016. A new lunar digital elevation model from the lunar orbiter laser altimeter and SELENE terrain camera, Icarus, 273, pp. 346-355. http://dx.doi.org/10.1016/j.icarus.2015.07.039

Haruyama, J. et al., 2012. Lunar global digital terrain model dataset produced from SELENE (Kaguya) terrain camera stereo observations. In: Lunar and Planetary Science Conference, p. 1200.

Rosenburg, M.A. et al. 2011. Global surface slopes and roughness of the Moon from the Lunar Orbiter, Journal of Geophysical Research, Vol. 116, E02001, http://dx.doi.org/10.1029/2010JE003716.

Product Keywords

MoonSLDEM2015topographyslopeazimuthLOLA