MESS MDIS MAP PROJ LOW-INCIDENCE ANGLE BASEMAP 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 Low- Incidence Angle Basemap RDRs (LOIs) which comprise a global map of I/F measured by the NAC or WAC filter 7 (both centered near 750 nm) during the Extended Mission at low solar incidence angles to accentuate albedo and albedo variations, 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 LOI data set is a companion to the Basemap Data Record (BDR) data set, High Incidence Angle Illuminated from the East (HIE) data set, and High Incidence Angle Illuminated from the West (HIW) data set, all of which are also composed of WAC filter 7 and NAC images, except acquired at higher solar incidence angles centered at 68 to 78 degrees to highlight topography. 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.