Cutting, Scaling, and Rearranging

Commands used for cutting, scaling, and rearranging data are listed below. Also see Normalization of Spectroscopy for commands applied most often to spectroscopic data, as well as Roughness Analysis for commands relevant to complex (real and imaginary) data arrays.


CreeP
arguments: creep (real)

Performs a lowest-order quadratic correction for creep in the data array, such that the first and last data points in the array maintain their positions, but other points are shifted according to:

i' = creep(i-1)(i-ncol) + i
i = -creep(i'-1)(i'-ncol) + i'  (approx)


CUT
arguments: min,max cols (integers)
           min,max rows (integers)

Cuts the data array at the specified columns (x-direction) and rows (y-direction).


CUt/c
arguments: no. regions (integer)
           min, max columns (integers)
           min, max rows (integers)     |  repeat no. regions times
           min, max cols (integers)
           min, max rows (integers)

Cuts the data array at specified regions (channels). The cut is performed at the specified columns, and includes data from all the specified rows regions.


DouBle
arguments: none

Doubles the numbers of rows, which data in pairs of rows being identical.


HAlf
arguments: none

Halves the numbers of rows, with data in every second row being discarded.


LImit
arguments: none

Searches for limit markers in the data, and discards the ends of the data array which extend beyond the limit markers. This is a specialized command used in conjunction with I(V) data acquired with the limiting option on, such that the voltage is limited only to those values for which the current is below a specified value.


MIrror
arguments: none

Performs a mirror reflection of the rows of data, such that the ordering of the rows 1,2,3, ... N is changed to N,N-1,N-2, ... 1. In other words, this command performs a mirror reflection about a horizontal line through the center of the data array. To achieve a mirror reflection about a vertical line, use the command sequence:

xy
mi
xy


MOdify/z
arguments: command (1=limit values, 2=modify z value, 3=strip off saturated values) (integer)
if command=1: min, max values (reals)
if command=2: row, column  (integer)
              new value (real)

Allows modification of specific elements of the data array. If command=1, then the z-values of limited by the specified bounds. If command=2, then the contents of the specified element is changed to the new value (this can occasionally be useful for testing purposes in the analysis). If command=3, then the data array is searched for saturated values (indicated by special values in spectroscopic data), and these values are stripped off from both ends of the array.


MOdify/x
arguments: multiplier (real)

Changes the x-calibration of the data by multiplying by multiplier.


SeLect options: /o /e
arguments: none

Selects either the odd numbered rows (with /o option) or the even numbered rows (with the /e option).


SHift/r
arguments: linear, quadratic shift per row (reals)

Shifts rows of the data array successively to the right according to:

i' = i + linear(j-1) + quadratic(j-1)²

where columns are labelled by i and rows by j. The size of the data array is enlarged to accomodate the blank regions created on either side, and these regions are padded with zeroes. Linear interpolation is used in computing new values.


SHift/x
arguments: xstart shift (real)

Shifts the value of the parameter "xstart", which gives the starting position of the first column of data.


SHift/z
arguments: min, max columns (integers)
           min, max rows (integers)
           z offset (real)

Shifts the specified regions of the data array by the amount z offset.


SQUare
arguments: none

Squares each value in the data array.


XY
arguments: none

Interchanges the x and y entries (columns and rows) of the data array.