OBJECT = DATA_SET_MAP_PROJECTION
DATA_SET_ID = "N/A"
OBJECT = DATA_SET_MAP_PROJECTION_INFO
MAP_PROJECTION_TYPE = SINUSOIDAL
MAP_PROJECTION_DESC = "
In the sinusoidal projection, parallels of latitude are straight
lines, with constant distances between equal latitude intervals.
Lines of constant longitude on either side of the projection
meridian are curved since longitude intervals decrease with the
cosine of latitude to account for their convergence toward the
poles.
The sinusoidal equal-area projection is characterized by a
projection longitude, which is the center meridian of the
projection, and a scale, which is given in units of pixels/radian.
The center latitude is the equator.
The transformation from latitude and longitude (LAT,LON) in radians
to LINE and SAMPLE is given by the following equations.
SCALE = 3393400/MAP_SCALE
LINE = LINE_PROJECTION_OFFSET-LAT*SCALE+0.5
SAMPLE = SAMPLE_PROJECTION_OFFSET +
(LON-CENTER_LONGITUDE)*SCALE*COS(LAT)+0.5
In the above definitions, integral values of LINE and SAMPLE
correspond to the center of a pixel, and the top left image pixel
has LINE=1 and SAMPLE=1. LAT and LON are the latitude and longitude
of a given spot on the surface in radians.
LINE_PROJECTION_OFFSET
is the image line number minus one on which the map projection
origin occurs. The map projection origin is the intersection of
the equator and the projection longitude CENTER_LONGITUDE. For the
sinusoidal projection, the value of LINE_PROJECTION_OFFSET is
positive for images starting north of the equator and is negative
for images starting south of the equator.
SAMPLE_PROJECTION_OFFSET
is the nearest image sample number to the left (west) of the
projection longitude CENTER_LONGITUDE. For the sinusoidal projection,
the value of SAMPLE_PROJECTION_OFFSET is positive for images starting
to the west of the projection longitude and is negative for images
starting to the east of the projection longitude.
CENTER_LONGITUDE
is the value of the projection longitude, which is typically the
longitude that passes through the center of the projection.
MAP_RESOLUTION
number of pixels per degree at the projection origin."
ROTATIONAL_ELEMENT_DESC = "See DAVIESETAL1989."
OBJECT = DS_MAP_PROJECTION_REF_INFO
REFERENCE_KEY_ID = "SNYDER1987"
END_OBJECT = DS_MAP_PROJECTION_REF_INFO
END_OBJECT = DATA_SET_MAP_PROJECTION_INFO
OBJECT = DATA_SET_MAP_PROJECTION_INFO
MAP_PROJECTION_TYPE = "SIMPLE CYLINDRICAL"
MAP_PROJECTION_DESC = "
In the simple cylindrical projection, parallels of latitude and
meridians of longitude are straight lines that intersect one another
at right angles.
Images in this projection are centered on the equator. Map resolution
is constant throughout the image, thus increasing distortion away from
the poles.
The transformation from latitude and longitude (LAT, LON) in degrees
to LINE and SAMPLE is given by the following equations.
SCALE = MAP_RESOLUTION
SAMPLE = SAMPLE_PROJECTION_OFFSET+SCALE*(LON-CENTER_LONGITUDE)+0.5
LINE = LINE_PROJECTION_OFFSET-SCALE*(LAT-CENTER_LATITUDE)+0.5
In the above definitions, integral values of LINE and SAMPLE
correspond to the center of a pixel, and the top left image pixel
has LINE=1 and SAMPLE=1. LAT and LON are the latitude and longitude
of a given spot on the surface in degrees.
LINE_PROJECTION_OFFSET
is the image line number minus one on which the map projection
origin occurs. The map projection origin is the intersection of
the equator and the projection longitude CENTER_LONGITUDE.
SAMPLE_PROJECTION_OFFSET
is the nearest image sample number to the left (west) of the
projection longitude CENTER_LONGITUDE.
CENTER_LONGITUDE
is the value of the projection longitude in degrees, which is
typically the longitude that passes through the center of the
projection.
MAP_RESOLUTION
number of pixels per degree at the projection origin."
ROTATIONAL_ELEMENT_DESC = "See DAVIESETAL1989."
OBJECT = DS_MAP_PROJECTION_REF_INFO
REFERENCE_KEY_ID = "SNYDER1987"
END_OBJECT = DS_MAP_PROJECTION_REF_INFO
END_OBJECT = DATA_SET_MAP_PROJECTION_INFO
OBJECT = DATA_SET_MAP_PROJECTION_INFO
MAP_PROJECTION_TYPE = STEREOGRAPHIC
MAP_PROJECTION_DESC = "
In the polar stereographic projection, parallels of latitude are
circles centered on the pole, and meridians of longitude are
straight lines radiating from the pole.
Images in this projection are centered on either the North or South
pole, with the central longitude (specified by the CENTER_LONGITUDE
value in the image label) running vertically from the pole to the
bottom of the image for the North Polar projection, and to the top
of the image for the South Polar projection.
The transformation from latitude and longitude (LAT, LON) in radians
to LINE and SAMPLE is given by the following equations.
SCALE = 3393400/MAP_SCALE
North Polar Stereographic:
SAMPLE = SAMPLE_PROJECTION_OFFSET +
2*SCALE*SIN(LON-CENTER_LONGITUDE)*TAN(PI/4-LAT/2)+0.5
LINE = LINE_PROJECTION_OFFSET +
2*SCALE*COS(LON-CENTER_LONGITUDE)*TAN(PI/4-LAT/2)+0.5
South Polar Stereographic:
SAMPLE = SAMPLE_PROJECTION_OFFSET +
2*SCALE*SIN(LON-CENTER_LONGITUDE)*TAN(PI/4+LAT/2)+0.5
LINE = LINE_PROJECTION_OFFSET -
2*SCALE*COS(LON-CENTER_LONGITUDE)*TAN(PI/4+LAT/2)+0.5
In the above definitions, integral values of LINE and SAMPLE
correspond to the center of a pixel, and the top left image pixel
has LINE=1 and SAMPLE=1. LAT and LON are the latitude and longitude
of a given spot on the surface in radians.
LINE_PROJECTION_OFFSET
is the image line number minus one on which the map projection
origin occurs. The map projection origin is the appropriate pole.
SAMPLE_PROJECTION_OFFSET
is the nearest image sample number to the left (west) of the
projection longitude CENTER_LONGITUDE.
CENTER_LONGITUDE
is the value of the projection longitude.
MAP_SCALE
pixel spacing at the projection origin, which is the appropriate
pole for stereographic images. The value is
in units of kilometers/pixel.
MAP_RESOLUTION
number of pixels per degree at the projection origin, which is
the appropriate pole for stereographic images."
ROTATIONAL_ELEMENT_DESC = "See DAVIESETAL1989."
OBJECT = DS_MAP_PROJECTION_REF_INFO
REFERENCE_KEY_ID = "SNYDER1987"
END_OBJECT = DS_MAP_PROJECTION_REF_INFO
END_OBJECT = DATA_SET_MAP_PROJECTION_INFO
OBJECT = DATA_SET_MAP_PROJECTION_INFO
MAP_PROJECTION_TYPE = MERCATOR
MAP_PROJECTION_DESC = "
In the Mercator projection, parallels of latitude and meridians
of longitude are straight lines that intersect one another at
right angles.
Images in this projection are centered on the equator. Pixel size
decreases with increasing latitude in order to retain conformality
(local preservation of shape).
The transformation from latitude and longitude (LAT, LON) in radians
to LINE and SAMPLE is given by the following equations.
SCALE = MAP_RESOLUTION*180/PI
SAMPLE = SAMPLE_PROJECTION_OFFSET+SCALE*(LON-CENTER_LONGITUDE)+0.5
LINE = LINE_PROJECTION_OFFSET-SCALE*LOG(TAN(PI/4+LAT/2))+0.5
In the above definitions, integral values of LINE and SAMPLE
correspond to the center of a pixel, and the top left image pixel
has LINE=1 and SAMPLE=1. LAT and LON are the latitude and longitude
of a given spot on the surface in radians, and LOG is the natural
logarithm function.
LINE_PROJECTION_OFFSET
is the image line number minus one on which the map projection
origin occurs. The map projection origin is the intersection of
the equator and the projection longitude CENTER_LONGITUDE. For the
Mercator projection, the value of LINE_PROJECTION_OFFSET is positive
for images starting north of the equator and is negative for images
starting south of the equator.
SAMPLE_PROJECTION_OFFSET
is the nearest image sample number to the left (west) of the
projection longitude CENTER_LONGITUDE. For the Mercator
projections, the value of SAMPLE_PROJECTION_OFFSET is positive for
images starting to the west of the projection longitude and is negative
for images starting to the east of the projection longitude.
CENTER_LONGITUDE
is the value of the projection longitude in radians, which is typically
the longitude that passes through the center of the projection.
MAP_RESOLUTION
number of pixels per degree at the projection origin, which is
latitude=0, longitude=0 for Mercator images."
ROTATIONAL_ELEMENT_DESC = "See DAVIESETAL1989."
OBJECT = DS_MAP_PROJECTION_REF_INFO
REFERENCE_KEY_ID = "SNYDER1987"
END_OBJECT = DS_MAP_PROJECTION_REF_INFO
END_OBJECT = DATA_SET_MAP_PROJECTION_INFO
END_OBJECT = DATA_SET_MAP_PROJECTION
END