Producing MESSENGER DEMs from MDIS NAC Images MANHEIM1, HENRIKSEN, ROBINSON, AND THE MESSENGER TEAM 1ARIZONA STATE UNIVERSITY, TEMPE AZ—
[email protected] Launched: August 2004 MESSENGER Mercury Orbit: March 2011 Completed: April 2015 Mercury Dual Imaging System (MDIS) 2 framing cameras: a monochrome NAC and a multispectral WAC NAC wasn’t a stereo camera, but off-nadir observations enable the creation of DEMs NACs have 5 m pixel scale at closest approach Mercury Laser Altimeter (MLA) Radial accuracy of < 20 m Only available between 90° N and 18° S Highly Elliptical Orbit Periapsis: 200 – 500 km (near North Pole) Apoapsis: 10,000 – 15,000 km Methodology: Overview Site Selection & Image Selection Illumination Conditions Imaging Geometry DEM Production Using the USGS Integrated Software for Imagers and Spectrometers (ISIS) and SOCET SET 5.6 Error analysis Creating data products for PDS release Image Selection Selecting stereo images requires compromise between finding optimal images and building up desired coverage. These parameters will dictate the precision of the final product. Strength of stereo: parallax between the two images / unit height Illumination compatibility: distance between the tips of shadows in two images / unit height *Guidelines adapted from Becker, et al. 2015. Images Selected for Our DEMs n=49 Selecting Images to Build Mosaics Sander Crater mosaic: 21 images Selecting Images to Build Mosaics Sander Crater mosaic: 21 images 36 stereo pairs (areas of overlap producing ‘good’ stereo) Selecting Images to Build Mosaics Sander Crater mosaic: 21 images 36 stereo pairs (areas of overlap producing ‘good’ stereo) Resulting DEMs can be mosaicked together (using ISIS) to create one large-area DEM Processing in SOCET SET: Overview Import into SOCET SET 5.6 Relative Triangulation Registration to MLA tracks DEM Extraction Orthophoto Generation Creating Additional Data Products PDS Release *This process is quite similar to that described for LROC NAC DEMs in Henriksen, et al.