| Description: The PDS3 name for this attribute was CSS:MIN_FOOTPRINT_LINE (with MAP_PROJECTION_TYPE = EQUIRECTANGULAR), and was defined as "Minimum size of footprints along the line axis". The meaning of this is unclear, but we believe it means the (angular) length along the vertical direction of the smallest footprint (a CIRS detector) on the pixel grid, and have renamed it in PDS4 accordingly as equirectangular_min_footprint_height. The equirectangular projection is used for observations of Saturn and its satellites, but not for the rings. The line coordinate is planetocentric or planetographic latitude (in units of degrees), which decreases with increasing sample index, so that map features appear correctly when the cube line/sample planes are displayed with sample index increasing from top to bottom. CAVEAT USOR: Several examples of CIRS cubes do not appear to correctly identify their min/max footprint width/heights. For example, some using equirectangular projection list their max footprint width as 360 deg, even when there is no wrapping. |