Code:

LABEL_REVISION_NOTE = "Ernest Bowman-Cisneros, 2011-03-08"
RECORD_TYPE = STREAM
SPACECRAFT_NAME = "LUNAR RECONNAISSANCE ORBITER"
TARGET_NAME = "MOON"
OBJECT = DATA_SET_MAP_PROJECTION
DATA_SET_ID = "LRO-L-LROC-5-RDR-V1.0"
OBJECT = DATA_SET_MAP_PROJECTION_INFO
MAP_PROJECTION_TYPE = "EQUIRECTANGULAR"
MAP_PROJECTION_DESC = "
The EQUIRECTANGULAR projection is based on the formula for a
sphere. To eliminate confusion in the IMAGE_MAP_PROJECTION
object we have set all three values, A_AXIS_RADIUS, B_AXIS_RADIUS,
and C_AXIS_RADIUS to the same number, which is R below.
The Equirectangular projection is a simple projection providing a
linear relationship between the geographic coordinates of latitude
and longitude and the Cartesian space of the map. In continuous
form, the equations relating map coordinates (x, y) to geographic
coordinates (Lat, Lon) are:
x = R * (Lon - LonP) * COS(LatP)
y = R * Lat
where LonP is the center longitude of the map projection,
LatP is the center latitude of the projection at which scale
is given, and R the radius of the body at the center latitude.
For the Moon R is assumed to be 1734.4 km.
The inverse formulas for Lat and Lon from x and y position in the
projection are:
Lat = y / R
Lon = LonP + x / (R * COS(LatP))
The Conversion from (x, y) map coordinates to image array
coordinates (sample, line) is standard for all map projections and
is:
x = (Sample - S0) * Scale
y = (-L0 - Line) * Scale
where Scale is the map resolution in km/pixel (located at the
center planetocentric latitude of the projection). Line and
Sample are the coordinates of the image array, and line (L0)
and sample offsets (S0) are the respective image coordinate
displacements from pixel (1,1) to the origin of the projection
(x,y) = (0,0). Please note, pixel (1,1) is spatially located
in the upper-left corner of the image array.
The equations from (x, y) to (Sample, Line) are:
Sample = x / Scale + S0 + 1
Line = -y / Scale - L0 + 1
The equation from (Sample, Line) to (Lat, Lon) is:
Lat = y / R
y = (1 - L0 - Line) * Scale
Lat = (1 - L0 - Line) * Scale / R
Lon = LonP + x / (R * COS(LatP))
x = (Sample - S0 - 1) * Scale
Lon = LonP + (Sample - S0 - 1) * Scale/ (R * COS(LatP))
The keywords corresponding to the Equirectangular projection
parameters are located in the IMAGE_MAP_PROJECTION object found
in the PDS labels. The keywords for each equation parameter are
shown below:
LonP | CENTER_LONGITUDE
LatP | CENTER_LATITUDE
L0 | LINE_PROJECTION_OFFSET
S0 | SAMPLE_PROJECTION_OFFSET
Scale | MAP_SCALE
R | A_AXIS_RADIUS (same as B_AXIS_RADIUS and
| C_AXIS_RADIUS)
"
END_OBJECT = DATA_SET_MAP_PROJECTION_INFO
OBJECT = DATA_SET_MAP_PROJECTION_INFO
MAP_PROJECTION_TYPE = "POLAR STEREOGRAPHIC"
MAP_PROJECTION_DESC = "
The Polar Stereographic projection, used for observations
acquired at higher latitudes, is ideally suited for observations
near the poles as shape and scale distortion are minimized. The
LROC derived products in Polar Stereographic projection use the
ellipsoid form of the equations.
In continuous form, the spherical equations relating map
coordinates (x, y) to planetocentric coordinates (Lat, Lon)
are:
North Polar Stereographic
x = 2 * Rp * TAN(Pi / 4 - Lat / 2) * SIN(Lon - LonP)
y = -2 * Rp * TAN(Pi / 4 - Lat / 2) * COS(Lon - LonP)
South Polar Stereographic
x = 2 * Rp * TAN(Pi / 4 + Lat / 2) * SIN(Lon - LonP)
y = 2 * Rp * TAN(Pi / 4 + Lat / 2) * COS(Lon - LonP)
Where LonP is the central longitude, LatP is the latitude of
true scale and is always 90 or -90, and Rp is the polar radius of
the Moon or 1,737.4 km.
The spherical inverse formulas for Lat and Lon from X and Y
position in the image array are:
Lat = ARCSIN[COS(C) * SIN(LatP) + y * SIN(C) * COS(LatP) / P]
North Polar Stereographic
Lon = LonP + ARCTAN[x / (-y)]
South Polar Stereographic
Lon = LonP + ARCTAN[x / y]
where:
P = SQRT(x^2 + y^2)
C = 2 * ARCTAN(P / 2 * Rp)
recall:
x = (Sample - S0 - 1) * Scale
y = (1 - L0 - Line) * Scale
The keywords corresponding to the equation parameters for the
Polar Stereographic projection are located in the
IMAGE_MAP_PROJECTION object found in the PDS labels. The
keywords for each equation parameter are shown below.
LonP | CENTER_LONGITUDE
LatP | CENTER_LATITUDE
L0 | LINE_PROJECTION_OFFSET
S0 | SAMPLE_PROJECTION_OFFSET
Scale | MAP_SCALE
R | A_AXIS_RADIUS (same as B_AXIS_RADIUS and
| C_AXIS_RADIUS)
"
END_OBJECT = DATA_SET_MAP_PROJECTION_INFO
OBJECT = DATA_SET_MAP_PROJECTION_INFO
MAP_PROJECTION_TYPE = "ORTHOGRAPHIC"
MAP_PROJECTION_DESC = "
The ORTHOGRAPHIC projection preserves neither area nor angle and
is a perspective projection from an infinite distance. Is also
referred to a view from space.
In continuous form, the spherical equations relating map coordinates
(x, y) to planetocentric geographic coordinates (Lat, Lon) are:
x = R * COS(Lat) * SIN(Lon - LonP)
y = R * [(COS(LatP) * SIN(Lat)) - (SIN(LatP) * COS(Lat) *
COS(Lon - LonP))]
where LonP is the center longitude of the map projection, LatP is the
center latitude of the projection at which the scale is given, and R
is the radius of the body at the center latitude. For the Moon, R is
given as 1737.4 km.
For the Orthographic projection, there are three special instances
where the equation for solving for y is modified, while finding x is
still found by the first equation:
1. North Polar Orthographic, where LatP = 90:
y = -R * COS(Lat) * COS(Lon - LonP)
2. South Polar Orthographic, where LatP = -90:
y = R * COS(Lat) * COS(Lon - LonP)
3. Equatorial Orthographic, where LatP = 0:
y = R * SIN(Lat)
The spherical inverse formulas to derive Lat and Lon from a given x
and y position in the projection are:
Lat = ARCSIN[COS(C) * SIN(LatP) + (y * SIN(C) * COS(LatP)/P)]
Lon = LonP + ARCTAN * [ (x * SIN(C)) / ((P * COS(LatP) * COS(C))
- (y * SIN(LatP) * SIN(C))]
If LatP = 90:
Lon = LonP + ARCTAN[x / (-y)]
If LatP = -90:
Lon = LonP + ARCTAN[x / y]
where:
P = SQRT(x2 + y2)
C = ARCSIN(P/R)
Standard map coordinates (x, y) to image array coordinates (Sample,
Line):
x = (Sample - S0 - 1) * Scale
y = (1 - L0 - Line) * Scale
where scale is...
NOTE: if Scale is negative, the point value is NULL (the feature
is beyond the curvature of the body)
The keywords corresponding to the Orthographic projection...
LonP | CENTER_LONGITUDE
LatP | CENTER_LATITUDE
L0 | LINE_PROJECTION_OFFSET
S0 | SAMPLE_PROJECTION_OFFSET
Scale | MAP_SCALE
R | A_AXIS_RADIUS (same as B_AXIS_RADIUS and C_AXIS_RADIUS)
"
END_OBJECT = DATA_SET_MAP_PROJECTION_INFO
OBJECT = DS_MAP_PROJECTION_REF_INFO
REFERENCE_KEY_ID = "SNYDER1987"
END_OBJECT = DS_MAP_PROJECTION_REF_INFO
END_OBJECT = DATA_SET_MAP_PROJECTION
END