If two inputs are used then both must have GeoTIFF labels and the mappings must be compatible for the size operation (only the scale and offset can differ). If a single input is used, then the GeoTIFF label is optional.
If the first input has a GeoTIFF label then a GeoTIFF label will be computed for the output taking into account the mapping, scale change, offset change, and (SL,SS) windowing.
In the simplest case of all, the size parameter is (1,1,NL,NS) and no itie,otie is used. The program magnifies/demagnifies the image to fit the output (NL,NS). The effect is as if the itie,otie was set to the outer corners of the outer corner pixels. The result will be the same as VICAR program SIZE. If a second input (GeoTIFF reference) is given, the size parameter is not used and an error occurs if it is given. In all other cases, the size parameter is a window on the output grid determined by ITIE,OTIE. If size is defaulted, then ITIE,OTIE must be given and the size parameter will be set to the smallest size to contain the "window" used by the tiepoints.
See second level help for SIZE parameter (type h size)
See second level help for SIZE parameter (type h size)
See second level help for SIZE parameter (type h size)
See second level help for SIZE parameter (type h size)
For example, a standard case of a 5 x 5 image to a 10 x 15
image treating the pixels as "areas" of data would use
itie=(0.5, 0.5, 5.5, 5.5)
otie=(0.5, 0.5, 10.5, 15.5)
to treat the pixels as center points and map the same
image sizes as above would use
itie=(1.0, 1.0, 5.0, 5.0)
otie=(1.0, 1.0, 10.0, 15.0)
See second level help for ITIE parameter (type h itie)
There are two types of zoom.
1. AZOOM (area zoom) which fixes the corners of the corner
pixels and zooms the interval between them the AZOOM value
which can be any floating point number greater than 0.0.
Note that an n x n image has distance n between the
corners of the corner pixels and it is this distance that
is zoomed. So the total size of the image from corner (of
corner pixel) to corner is approximately AZOOM*n. Fractional
pixels may be discarded since the output image must be in
whole pixels. The scale change will be exactly AZOOM always.
2. PZOOM (point zoom) which fixes the centers of the corner
pixels and zooms the interval between them the PZOOM value
which can be any floating point number greater than 0.0.
Note that an n x n image has distance (n-1) between the
centers of the corner pixels and it is this distance that
is zoomed. So the total size of the image from corner (of
corner pixel) to corner is PZOOM*(n-1)+1 or the closest
value to that if fractional pixels are involved. The scale
change will be exactly PZOOM always. Using PZOOM=2.0 for a
DTED image would cause the 601 x 1201 size to become
1201 x 2401.
In either case, a zoom of 2.0 approximately doubles the image
size in pixels and a zoom of 0.5 halves the image size in pixels.
Both zooms preserve GeoTIFF label mappings. The pixel scale is
always changed by an exact amount given by the zoom parameter,
to 15 decimal places.
A negative value of zoom is interpreted as -1/zoom, for example,
pzoom=-4 is the same as pzoom=0.25.
There are two types of zoom.
1. AZOOM (area zoom) which fixes the corners of the corner
pixels and zooms the interval between them the AZOOM value
which can be any floating point number greater than 0.0.
Note that an n x n image has distance n between the
corners of the corner pixels and it is this distance that
is zoomed. So the total size of the image from corner (of
corner pixel) to corner is approximately AZOOM*n. Fractional
pixels may be discarded since the output image must be in
whole pixels. The scale change will be exactly AZOOM always.
2. PZOOM (point zoom) which fixes the centers of the corner
pixels and zooms the interval between them the PZOOM value
which can be any floating point number greater than 0.0.
Note that an n x n image has distance (n-1) between the
centers of the corner pixels and it is this distance that
is zoomed. So the total size of the image from corner (of
corner pixel) to corner is PZOOM*(n-1)+1 or the closest
value to that if fractional pixels are involved. The scale
change will be exactly PZOOM always. Using PZOOM=2.0 for a
DTED image would cause the 601 x 1201 size to become
1201 x 2401.
In either case, a zoom of 2.0 approximately doubles the image
size in pixels and a zoom of 0.5 halves the image size in pixels.
Both zooms preserve GeoTIFF label mappings. The pixel scale is
always changed by an exact amount given by the zoom parameter,
to 15 decimal places.
A negative value of zoom is interpreted as -1/zoom, for example,
pzoom=-4 is the same as pzoom=0.25.
The two cases for this keyword are: COVERREF and COVERINP.
NORMAL CASE IS AS FOLLOWS ('COVERREF), ALSO THE DEFAULT
COVERREF means that the output will adjust to cover the
GeoTIFF reference image (the second input). Both inputs
must have GeoTIFF labels and the geographic mappings must
agree. The scales and offsets can differ. The GeoTIFF
mappings will be used to calculate all details of the
resize operation. This option can be used to make a stack
of geographically identical images, all with the same (nl,ns).
THE SECOND OPTION ('COVERINP) USEFUL FOR MOSAICKING AND DB
The other option (COVERINP) uses the reference image to
determine the mapping but ignores the reference image
frame. It instead looks at the input image frame and
converts the entire input image. Two things can still be
changed by this option:
1. The pixel "size", actually, the ratio of mapping
coordinates per pixel. These ratios can be deter-
mined by dividing the corner point coordinate
difference by the number of pixels in the image.
Horizontal and vertical are treated separately.
2. The pixel "shift". Even if the pixel size for
the two images agree, they may not mosaic together
accurately because the pixel centers do not align.
Use of the typref parameter guarantees that both of these
problems will be corrected. You can check this by looking
at the shifts written for each frame in FEATHER. They should
all have a fraction of .000000 shown on their offsets.
Another example of this option ... the user can set up
an area or worldwide mapping by creating a GeoTIFF image
of a small subarea. Other images can be put into a matching
raster grid by using the small area as a reference image.
The main effect will be to give the same scale and fractional
pixel offset so that tiles and mosaics will butt together
perfectly.