1 REPROJECT Reproject an input image/cube to a different projection system
REPROJECT
This task resamples an input image to a different projection and coordi-
nate system. Bilinear interpolation is used. Hence the pixel size (in-
crement) of the output image shoud be smaller than the input image one.
The task works on data cubes, processing them plane by plane.
For its needs, the task will allocate memory up to the value provided by
the Sic logical SPACE_GILDAS. You can tune this value by putting e.g.
the following line in the file ~/.gag.dico to enlarge its capabilities
(units MB):
SPACE_GILDAS 256
2 Y_NAME$
TASK\FILE "Input file" Y_NAME$
The name of the image you want to reproject.
2 X_NAME$
TASK\FILE "Output file" X_NAME$
The name of the output reprojected image.
2 PROJECTION$
TASK\CHARACTER "Projection type" PROJECTION$
The name of the projection type. The supported projection types are
GNOMONIC, ORTHOGRAPHIC, AZIMUTHAL, STEREOGRAPHIC, AITOFF, RADIO, SFL,
MOLLWEIDE, NCP, CARTESIAN and NONE (no projection).
2 SYSTEM$
TASK\CHARACTER "Coordinate system type" SYSTEM$
The name of the coordinate system. The supported coordinate systems are
EQUATORIAL [epoch], EQUATORIAL 2000, GALACTIC, and UNCHANGED.
2 CENTER_1$
TASK\CHARACTER "Coordinates of projection center" CENTER_1$
The First Coordinate of the new projection center (in the new coordinate
system of course). Accepts any formats from sexagesimal (HH:MM:SS.SS )
to decimal. Expects to read HOURS if the system is EQUATORIAL, DEGREES
if not.
2 CENTER_2$
TASK\CHARACTER "Coordinates of projection center" CENTER_2$
The Second Coordinate of the new projection center (in the new
coordinate system of course). Accepts any formats from sexagesimal
(HH:MM:SS.SS ) to decimal. Expects the value to be in DEGREES.
2 ANGLE$
TASK\REAL "Position angle of projection" ANGLE$
The position angle of the projection (in degrees).
2 DIMENSIONS$
TASK\REAL "Dimensions of output image" DIMENSIONS$[2]
The size in pixels of the reprojected image. 0 means automatic: the to-
tal number of pixels will be doubled (sqrt(2) factor on each axis).
2 AXIS_1$
TASK\REAL "First axis conversion formula" AXIS_1$[3]
The conversion formula for the first axis of the reprojected image:
- Ref: the reference pixel (NOT IMPLEMENTED: automatic value is used
instead)
- Val: the value of the axis at the reference pixel (NOT IMPLEMENTED:
automatic value is used intead)
- Inc: the distance between two pixels on the axis.
Zero values means automatic definition by the task:
- Inc: is set so that the DIMENSIONS[1] pixels cover the 1st axis of
the new grid.
- Val: is set to 0.0 i.e. the Reference pixel is aligned on the
projection center.
- Ref: is set so that the left boundary of the 1st axis of the new
grid is in the 1st pixel, and is rounded to the nearest integer
value towards DIMENSIONS[1]/2+1, so that the projection center is at
the center of a pixel.
2 AXIS_2$
TASK\REAL "Second axis conversion formula" AXIS_2$[3]
The conversion formula for the second axis of the reprojected image:
- Ref: the reference pixel (NOT IMPLEMENTED: automatic value is used
instead)
- Val: the value of the axis at the reference pixel (NOT IMPLEMENTED:
automatic value is used intead)
- Inc: the distance between two pixels on the axis.
Zero values means automatic definition by the task:
- Inc: is set so that the DIMENSIONS[2] pixels cover the 2nd axis of
the new grid.
- Val: is set to 0.0 i.e. the Reference pixel is aligned on the
projection center.
- Ref: is set so that the bottom boundary of the 2nd axis of the new
grid is in the 1st pixel, and is rounded to the nearest integer
value towards DIMENSIONS[2]/2+1, so that the projection center is at
the center of a pixel.
2 CHANGE$
TASK\LOGICAL "Change blanking value" CHANGE$
Answer YES if you want to modify the blanking value, NO other-
wise.
2 BLANKING$
TASK\REAL "New blanking value and tolerance" BLANKING$[2]
The new values of the blanking and tolerance on blanking.
1 ENDOFHELP