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. 2017. 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. 2017. 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. 2017. Registration to MLA

NAC

 Not always possible: for DEMs with little coverage, or further south, there may be little or no MLA coverage. WAC

 In this case, find an overlapping stereo pair of WAC images

 Tie NACs to the WACs

 WACs are manually registered to MLA

 NACs and WACs are bundle-adjusted together for absolute orientation MLA 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. 2017. 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. 2017. 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. 2017. Data Products

 Sander DEM: 21 images, 36 stereo pairs

 A readme file was also produced for each DEM, containing error analysis results. Error Analysis

 Vertical precision (“relative linear error”) is calculated by SOCET SET at a 90% confidence level

 expected to be < DEM pixel scale DEMs Produced at ASU Center MLA No. of Latitude, Mosaic Relative Mean Stereo Longitude Pixel Linear Offset MLA Standard Site Name Pairs (°N, °E) Scale (m) Error (m) (m) Deviation (m) Catullus Crater* 1 21.88°, 292.5° 84 84 -255 188 Cunningham Crater 9 30.40°, 157.0° 105 85 2 58 Degas Crater 1 36.86°, 232.6° 97 70 -1 109

Hynek Scarp (unofficial name) 1 -31.16°, 82.5° 500 383 - - Kertesz Crater* 2 31.45°, 146.3° 120 98 -9 51 Kuiper Crater 1 -11.3°, 329.1° 270 161 - -

Paramour Rupes* 3 -5.07°, 145.1° 450 261 -5 185 Raditladi Hollows 3 15.20°, 120.2° 180 137 -44 52 Sander Crater 36 42.50°, 154.7° 162 70 -44 65 *Error analysis was performed on WAC images which were tied to the NAC DEMs. Error Analysis

 Positional Accuracy: Compare to MLA

 Only possible for DEMs with overlapping MLA tracks (northern hemisphere)

 Ideally, offsets are < 20 m (the radial accuracy of MLA) DEMs Produced at ASU Center MLA No. of Latitude, Mosaic Relative Mean Stereo Longitude Pixel Linear Offset MLA Standard Site Name Pairs (°N, °E) Scale (m) Error (m) (m) Deviation (m) Catullus Crater* 1 21.88°, 292.5° 84 84 -255 188 Cunningham Crater 9 30.40°, 157.0° 105 85 2 58 Degas Crater 1 36.86°, 232.6° 97 70 -1 109

Hynek Scarp (unofficial name) 1 -31.16°, 82.5° 500 383 - - Kertesz Crater* 2 31.45°, 146.3° 120 98 -9 51 Kuiper Crater 1 -11.3°, 329.1° 270 161 - -

Paramour Rupes* 3 -5.07°, 145.1° 450 261 -5 185 Raditladi Hollows 3 15.20°, 120.2° 180 137 -44 52 Sander Crater 36 42.50°, 154.7° 162 70 -44 65 *Error analysis was performed on WAC DEMs which were tied to the NAC DEMs. DEMs Produced at ASU Center MLA No. of Latitude, Mosaic Relative Mean Stereo Longitude Pixel Linear Offset MLA Standard Site Name Pairs (°N, °E) Scale (m) Error (m) (m) Deviation (m) Catullus Crater* 1 21.88°, 292.5° 84 84 -255 188 Cunningham Crater 9 30.40°, 157.0° 105 85 2 58 Degas Crater 1 36.86°, 232.6° 97 70 -1 109

Hynek Scarp (unofficial name) 1 -31.16°, 82.5° 500 383 - - Kertesz Crater* 2 31.45°, 146.3° 120 98 -9 51 Kuiper Crater 1 -11.3°, 329.1° 270 161 - -

Paramour Rupes* 3 -5.07°, 145.1° 450 261 -5 185 Raditladi Hollows 3 15.20°, 120.2° 180 137 -44 52 Sander Crater 36 42.50°, 154.7° 162 70 -44 65 *Error analysis was performed on WAC DEMs which were tied to the NAC DEMs. PDS Release

 All MDIS NAC DEMs and associated products produced at ASU were released to the public through the PDS in December 2016. PDS Release

 All MDIS NAC DEMs and associated products produced at ASU were released to the public through the PDS in December 2016.

https://pds-imaging.jpl.nasa.gov/volumes/mess.html References [1] Becker, K. J. et al. (2015) LPS, 46, Abs. 2703. [2] Henriksen, M. R. et al. (2017) Icarus, 283, 122-137. [3] Cavanaugh, J. F. et al. (2007) Space Sci. Rev., 131, 451-497. [4] Fassett, C. I. (2016) Planet. Space Sci., 134, 19-28. [5] Zuber, M. T. et al. (2012) Science, 336, 217-220. [6] Anderson, J. A. et al. (2004) LPS, 35, Abs. 2039. [7] Becker, K. J. et al. (2016) LPS, 47, Abs. 2959. [8] Förstner, W. et al. (2013) Manual of Photogrammetry (6th ed.), 785-955. [9] BAE Systems (2011) SOCET SET User's Manual, v. 5.6. [10] BAE Systems (2007) NGATE. White Paper. [11] Zhang, B. (2006) ASPRS, p. 12. [12] Miller, S. et al. (2013) Manual of Photogrammetry (6th ed.), 1009- 1043. [13] Warmerdam, F. (2008) Open Source Approaches in Spatial Data Handling, 87- 108. [14] Hawkins, S. E., III et al. (2007) Space Sci. Rev., 131, 247-338.