Input IBIS graphics-1 file. (This file may be in IBIS1 or IBIS2 format.)
Output IBIS graphics-1 file to be created. (This file will be in IBIS2 format.)
PLANET is the name of the target body (up to 12 characters). The subroutine PBDATA (containing the radii of the nine planets and and their moons) is called to obtain the appropriate radii.
Each possible projection type is described below.
'MERCATOR specifies a Mercator projection.
This projection maps the sphere, except for the two poles, onto a
strip on the plane. The width of the strip is equal to the scaled
circumference of the planet at the equator. It extends infinitely
in both vertical directions. Longitude lines project to the
infinitely long, vertical straight lines which are equally spaced.
Latitude circles become horizontal line segments whose spacing
increases without limit as you approach the pole. The Mercator is a
conformal projection (scale errors at any point are equal in all
directions, so shapes of small areas are preserved).
The MERCator projection works somewhat differently than before the
port to UNIX:
LINE The line in the output to which LATITUDE will project.
Defaults to 1.0.
SAMPLE The sample in the output to which LONGITUDE will project.
Defaults to 1.0.
LATITUDE The latitude of LINE in the output.
Default computes latitude to center input in output.
LONGITUDE The longitude of SAMPLE in the output.
Default computes longitude to center input in output.
'LAMBERT specifies a Two-Standard Lambert Conformal Conic
projection. In this projection two latitude parallels on the same
side of the equator are chosen as "standard". There will be no
scale error any where on these parallels. In addition, some
longitude is chosen as "central". The projection is developed on a
cone which intersects the planet at the standard parallels. This
cone is cut along the meridian 180 degrees away from the central
meridian. The result is that the sphere is mapped onto the region
between two semi-infinite rays emanating from the projection of the
pole in the same hemisphere as the standard parallels. The opposite
pole is the only point on the sphere which is not mapped. Longitude
meridians become semi-infinite rays emanating from the visible
pole, but not at their true angle since all longitudes are confined
to lie between the two outermost rays, each of which represent the
meridian along which the cone was cut. The central meridian is the
only vertical line among the longitude meridians. Latitude circles
become circular arcs centered on the projected pole and confined
between the outer longitude meridians. The longitude rays are
equally spaced. The latitude circles are too widely spaced outside
the standards and too closely spaced between them. The spacing of
the latitude circles increases without limit as you approach the
opposite pole. As its name inmplies, this projection is conformal.
Neither the Mercator nor the Lambert are true perspective projections.
PARAL1 and PARAL2 are the latitudes of the standard parallels.
The LONGITUD parameter specifies the central meridian.
The line origin is the pole.
The sample origin is central meridian.
'CYLINDRI requests the cylindrical (normal) projection.
This projection maps the sphere onto a strip on the plane. The width
of the strip is equal to the scaled circumference of the planet at
the equator. Longitude lines project to vertical lines which are
equally spaced and extend from one pole to the other. Latitude
circles become horizontal lines whose spacing varies as the cosine
of the latitude. The cylindrical projection is an equal area
projection.
The LATITUDE parameter specifies the line origin.
The LONGITUD parameter specifies the sample origin.
'RECTANGU requests the Simple Cylindrical (Rectangular) projection.
This projection is similar to the Normal Cylindrical except that
the spacing of the latitude circles (horizontal lines) is constant
with and is equal to the spacing of the longitude lines.
The LATITUDE parameter specifies the line origin.
The LONGITUD parameter specifies the sample origin.
'POLSTERE requests an Polar Stereographic projection.
The stereographic is true perspective projection. The projection plane
is tangent to the planet at the pole. Perspective lines emanate from
the other pole. Thus the entire sphere except for one point is mapped
to the entire plane. Longitude meridians are straight lines intersecting
at the pole at their correct angles. Latitude circles project to complete
circles centered on the pole. The projection is conformal. Features are
expanded more and more without limit as you move away from the center of
projection.
The LONGITUD parameter specifies the meridian that is in the
"up" direction in the line-sample space.
The POLE parameter specifies which pole.
'STEREOGR requests an Oblique Stereographic projection.
The stereographic is true perspective projection. A plane is placed
tangent to the sphere at the center of projection. Perspective lines
emanate from the point on the sphere diametrically opposite from the
center of projection. Thus the entire sphere except for one point is
mapped to the entire plane. Longitude lines and latitude circles
project to ellipses whose spacing and orientation vary in a
complicated way. The projection is conformal. Features are expanded
more and more without limit as you move away from the center of projection.
The LATITUDE and LONGITUD parameters specify the center of
projection (i.e. the point on the planet directly below
perspective point).
The NORTHANG parameter specifies the orientation of the projection.
The line origin is the center of projection.
The sample origin is the center of projection.
'POLORTHO requests an Polar Orthographic projection.
This is a true perspective projection with perspective point at
infinity. The projection plane is tangent to the planet at the pole.
Longitude meridians are straight lines intersectiong at the pole at
their correct angles. Latitude circles project to complete circles
centered on the pole. The hemisphere centered at the pole is mapped
to a circle on the plane of radius Req. Features are compressed
relative to their true scale as you move away from the pole. No point
in the other hemisphere can be projected.
The LONGITUD parameter specifies the meridian that is in the
"up" direction in the line-sample space.
The POLE parameter specifies which pole.
'ORTHOGRA requests an Oblique Orthographic projection.
This is a true perspective projection with perspective point at
infinity. The projection plane is tangent to the planet at the center
of projection. Perspective lines are parallel to each other,
perpendicular to the projection plane. Thus one hemisphere centered
at the center of projection is mapped to a circle on the plane of
radius Req. Longitude meridians and latitude circles map to
ellipses. Features are compressed relative to their true scale as
you move away from the center of projection. No point more than 90
degrees away from the center can be projected. This projection is
frequently used by space projects because it makes the input frame
appear much as it would from the spacecraft if it were directly
above the center of projection.
The LATITUDE and LONGITUD parameters specify the center of
projection (i.e. the point on the planet directly below
perspective point).
The NORTHANG parameter specifies the orientation of the projection.
The line origin is the center of projection.
The sample origin is the center of projection.
'OBLICYL requests an Oblique Simple Cylindrical projection.
The scale is correct along the oblique equator.
The LATITUDE and LONGITUD parameters specify the center of
projection
The NORTHANG parameter specifies the orientation of the projection.
The line origin is the center of projection.
The sample origin is the center of projection.
'SINUSOID requests a Sinusoidal Equal Area Projection of the authalic sphere.
Latitude parallels are equally space in the line direction. Longitude
meridians are sinusoidal lines, except for the central meridian which is a
straight vertical line. The latitude scale is correct everywhere, and the
longitude scale is correct along the central meridian. Distortion
increases away from the central meridian.
The LONGITUD parameter specifies the central meridian.
The line origin is the equator (latitude = 0).
The sample origin is the central meridian.
'OBSINUSO requests Oblique sinusoidal projection. Same as sinusoidal except
the sphere can be rotated before the projection is performed.
LINE specifies the location of latitude=0,
SAMP specifies that of longitude=180.
LATI and LONG specify the position of the North pole.
PARAL1 is the longitude to which LONG will move.
'MOLLWEID requests the mollweid projection. Equal area. Latitudes are
straight parallel lines. Longitudes converge on the poles. Scale is true
at latitudes +/- 40 deg 44 min.
LINE The output line of latitude 0.
Defaults to the center of the output.
SAMPLE The output sample of the reference longitude
specified by LONGITUDE.
Defaults to the center of the output.
LATITUDE not used.
LONGITUDE The REFERENCE longitude for the projection.
Will be a vertical line in the output.
Defaults to the center of the input.
SCALE The scale in km/pixel at latitude 40 deg 44 min N or S.
'TMERCATO requests the Transverse mercator projection. Same as Mercator
except the central meridian is substituted for the equator, permitting both
poles to be seen. Central meridian, other meridians 90 degrees distant,
and the equator are straight lines.
LINE The output line of the latitude specified by LATITUDE.
Defaults to the center of the output.
SAMPLE The output sample of the reference longitude
specified by LONGITUDE.
Defaults to the center of the output.
LATITUDE The latitude placed at LINE in the output.
Defaults to the center of the input.
LONGITUDE The REFERENCE longitude for the projection
( That longitude which maps to a vertical line ).
Defaults to the center of the input.
SCALE The scale in km/pixel at central meridian.
SCALE represents the scale, in km/pixel, at the undistorted (see under PROJ) part of the projection.
The LINE parameter specifies the translation of the line-sample space in the line direction. LINE is the line coordinate of the line origin. (E.g. for a Lambert projection the pole has a line coordinate given by the LINE parameter). In AUTO placement mode the LINE parameter specifies the minimum output line of the region.
The SAMPLE parameter specifies the translation of the line-sample space in the sample direction. SAMPLE is the sample coordinate of the sample origin. (E.g. for a Lambert projection the central meridian has a sample coordinate given by the SAMPLE parameter). In AUTO placement mode the SAMPLE parameter specifies the minimum output sample of the region.
The LATITUDE parameter specifies the special latitude. See the help for the PROJ parameter on the particular use of the parameter for the desired map projection.
The LONGITUD parameter specifies the special longitude. See the help for the PROJ parameter on the particular use of the parameter for the desired map projection.
PARAL1 and PARAL2 are used mainly for the Lambert projection. They are the latitudes of the two standard parallels which define the projection. This parameter is also used to specify the special longitude in the Oblique projections.
PARAL2 is used only for the Lambert projection. They are the latitudes of the two standard parallels which define the projection.
NORTHANG is used only for Oblique Stereographic, Oblique Orthographic, and Oblique Cylindrical projections. NORTHANG is the angle in degrees of north in the output space. This angle is measured in the projection plane at the center of projection clockwise from up.
POLE is only used for the Polar Orthographic and Polar Stereographic projections. POLE specifies the pole visible in the projection, either NORTH or SOUTH.
PLACEMEN is a keyword the specifies the placement of the lat-long in the line-sample space. The default is for the placement to depend on the LINE and SAMPLE parameters. 'AUTOMAT will cause the special line and sample to be calculated so that latitudes and longitudes inside the LATRANGE, LONRANGE box will project to only positive line and samples. 'AUTO placement can only be used for a forward transformation.
LATRANGE specifies the minimum and maximum latitude of the box to be used in the 'AUTO placement mode.
LONRANGE specifies the minimum and maximum longitude of the box to be used in the 'AUTO placement mode.
The number of nominal data values to skip over in the graphics-1 file. These data values are carried along to the output graphics file without modification.