MESS MDIS MAP PROJ HIGH-INCIDENCE BASEMAP WEST RDR V1.0

Abstract ======== The Mercury Dual Imaging System (MDIS) consists of two cameras, a Wide Angle Camera (WAC) and a Narrow Angle Camera (NAC), mounted on a common pivot platform. This dataset includes Map Projected High- Incidence Angle Basemap Illuminated from the West RDRs (HIWs) which comprise a global map of I/F measured by the NAC or WAC filter 7 (both centered near 750 nm) during the the Extended Mission at high incidence angles to accentuate subtle topography, photometrically normalized to a solar incidence angle (i) = 30 degrees, emission angle (e) = 0 degrees, and phase angle (g) = 30 degrees at a spatial sampling of 256 pixels per degree. The HIW data set is a companion to the Map Projected High-Incidence Angle Basemap Illuminated from the East RDR (HIE) data set. Together the two data sets are intended to detect and allow the mapping of subtle topography. They complement a Basemap Data Record (BDR) data set also composed of WAC filter 7 and NAC images acquired at moderate/high solar incidence angles centered near 68 degrees (changed to 74 degrees in the find end-of-mission data delivery), and an Low Incidence Angle (LOI) data set also composed of WAC filter 7 and NAC images acquired at lower incidence centered near 45 degrees, analogous to the geometry used for color imaging. The map is divided into 54 'tiles', each representing the NW, NE, SW, or SE quadrant of one of the 13 non-polar or one of the 2 polar quadrangles or 'Mercury charts' already defined by the USGS. Each tile also contains 5 backplanes: observation ID; BDR metric, a metric used to determine the stacking order of component images, modified for the higher incidence angle centered near 78 degrees; solar incidence angle; emission angle; and phase angle.