PDS_VERSION_ID = PDS3 PRODUCT_TYPE = "DDR" RECORD_TYPE = STREAM SPACECRAFT_NAME = "NEW HORIZONS" TARGET_NAME = "PLUTO" OBJECT = DATA_SET_MAP_PROJECTION DATA_SET_ID = "NH-P/PSA-LEISA/MVIC-5-COMP-V1.0" OBJECT = DATA_SET_MAP_PROJECTION_INFO MAP_PROJECTION_TYPE = "SIMPLE CYLINDRICAL" MAP_PROJECTION_DESC = " The global mosaics are presented in a simple cylindrical map projection [SNYDER1987]. This projection is neither equal-area nor conformal. The meridians, and parallels are equidistant straight lines, intersecting at right angles. This map projection is centered on the equator. The map resolution is constant throughout the image. The transformation from latitude and longitude to line and sample is given by the following equations. Longitude increases from west to east and is non-negative. sample = RND( SAMPLE_PROJECTION_OFFSET + RES * (lon - CENTER_LONGITUDE) ) + 1 line = RND( LINE_PROJECTION_OFFSET - RES * (lat - CENTER_LATITUDE) ) + 1 RND is defined here as rounding the enclosed value to the nearest integer value, and the tie-breaking method for half-integers is to round them to the nearest even integer, in accordance with the IEEE 754 standard, as implemented in the Fortran NINT() function. lat and lon: These are the latitude and longitude of a given spot on the surface in degrees. The following variables: LINE_PROJECTION_OFFSET, SAMPLE_PROJECTION_OFFSET, CENTER_LONGITUDE, CENTER_LATITUDE, and MAP_RESOLUTION are found in the IMAGE_MAP_PROJECTION object in an image's PDS label. LINE_PROJECTION_OFFSET is a value which provides the line offset value of the map projection origin position from the line and sample (1,1). Line and sample 1,1 is considered the upper left corner of the digital array). SAMPLE_PROJECTION_OFFSET is a value which provides the sample offset value of the map projection origin position from line and sample (1,1). Line and sample 1,1 is considered the upper left corner of the digital array). CENTER_LONGITUDE and CENTER_LATITUDE are the longitude and latitude chosen as the origin of the map projection. RES (MAP_RESOLUTION) is the number of pixels per degree at the projection origin. Note that in these equations, the offset of 1 is part of the equation, so that the result of rounding the expression to the nearest whole number will produce a value of (1,1) for a point whose longitude and latitude lie inside the upper left-most pixel and for which LINE_PROJECTION_OFFSET and SAMPLE_PROJECTION_OFFSET are both zero. The inverse transformation from the center of the pixel (sample,line) is lon = CENTER_LONGITUDE + (sample - SAMPLE_PROJECTION_OFFSET - 1) / RES lat = CENTER_LATITUDE - (line - LINE_PROJECTION_OFFSET - 1) / RES For a map resolution of one degree per pixel, spanning longitudes from 0 to 360 degrees of longitude and from -90 to 90 degrees in latitude, with CENTER_LONGITUDE = 180 degrees and CENTER_LATITUDE = 0 degrees, a point lying in the open interval (0-1) degrees in longitude must lie in sample 1. Thus, SAMPLE_PROJECTION_OFFSET = 179.5 so that for a point at 0.5 degree longitude, sample = RND( 179.5 + 1*(0.5 - 180.0) ) + 1 will result in a value of 1. The value 1 is added after rounding so that longitude 0 also is in sample 1. As a convention, longitude 360 lies within the last sample, although this value should not occur in a standard conversion of angles to degrees. Similarly, LINE_PROJECTION_OFFSET = 89.5 in this example. For a point lying midway between 89 and 90 degrees latitude, line = RND(89.5 - 1*(89.5 - 0.0)) + 1 will result in a value of 1. As a convention, latitude -90 lies within the last line. These equations refer to a digital array in which the positive direction is to the right and down. In the above definitions, a pixel is assumed to cover an area, and the integral values of line and sample are assumed to correspond to the center of the area. The pixel in the upper left corner is line 1, sample 1. The latitude and longitude corresponding to the center of pixel (1,1) are maximum latitude - 1/(RES*2) and westernmost longitude + 1/(RES*2). The top edge of pixel (1,1) has the maximum latitude in the image. The left edge of pixel (1,1) has westernmost longitude in the image. There are four PDS parameters that specify the latitude and longitude bounding box of a map. MAXIMUM_LATITUDE and MINIMUM_LATITUDE specify the latitude extents of the map, and EASTERNMOST_LONGITUDE and WESTERNMOST_LONGITUDE specify the longitudinal extents of the map. Definitions of other mapping parameters can be found in the PDS Data dictionary. " ROTATIONAL_ELEMENT_DESC = "See [ZANGARI2015] and [NIMMOETAL2017] for Pluto and Charon pole definitions." OBJECT = DS_MAP_PROJECTION_REF_INFO REFERENCE_KEY_ID = "SNYDER1987" END_OBJECT = DS_MAP_PROJECTION_REF_INFO OBJECT = DS_MAP_PROJECTION_REF_INFO REFERENCE_KEY_ID = "ZANGARI2015" END_OBJECT = DS_MAP_PROJECTION_REF_INFO OBJECT = DS_MAP_PROJECTION_REF_INFO REFERENCE_KEY_ID = "NIMMOETAL2017" END_OBJECT = DS_MAP_PROJECTION_REF_INFO END_OBJECT = DATA_SET_MAP_PROJECTION_INFO END_OBJECT = DATA_SET_MAP_PROJECTION END