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