Convert Pixel Image to Another Unit of Length
Converts a pixel image to another unit of length.
## S3 method for class 'im' rescale(X, s, unitname)
X |
Pixel image (object of class |
s |
Conversion factor: the new units are |
unitname |
Optional. New name for the unit of length.
See |
This is a method for the generic function rescale.
The spatial coordinates of the pixels in X
will be re-expressed
in terms of a new unit of length that is s times the current
unit of length given in X.
(Thus, the coordinate values are divided by s,
while the unit value is multiplied by s).
If s is missing, then the coordinates will be re-expressed
in ‘native’ units; for example if the current unit is
equal to 0.1 metres, then the coordinates will be re-expressed in metres.
The result is a pixel image representing the same data but re-expressed in a different unit.
Pixel values are unchanged. This may not be what you intended!
Another pixel image (of class "im"),
containing the same pixel values, but with pixel coordinates
expressed in the new units.
Adrian Baddeley Adrian.Baddeley@curtin.edu.au
and Rolf Turner r.turner@auckland.ac.nz
# Bramble Canes data: 1 unit = 9 metres data(bramblecanes) # distance transform Z <- distmap(bramblecanes) # convert to metres # first alter the pixel values Zm <- eval.im(9 * Z) # now rescale the pixel coordinates Z <- rescale(Zm, 1/9) # or equivalently Z <- rescale(Zm)
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