Band diff command

Seadisp Band Difference Command (band_diff)

Description: General display program command mode procedure for differencing any two loaded bands and creating a new data array as a result. The newly created array will be made available to the user in the next available band number.

Navigation information for the resultant output array will be copied from the first input band. Warnings are issued if the units are not the same for all inputs. In the case of the /raw option, warnings will also be issued if the raw data types are not the same for input grids as well as the slope, intercept and scale type conversion values used to convert from raw to geophysical values.

Note: The command mode procedure load must be run before band_diff.

Usage: band_diff, band_no=band_no, /raw, /geo, min=min, max=max, ignore=ignore, tol=tol, replace=replace, /exclusive, /inclusive, err=err

Examples:

Difference loaded bands 1 and 2 in terms of geophysical data values (the default).

band_diff, band_no=[1,2]

Difference loaded bands 1 and 3. Only compute a difference where both data values are greater than or equal to 0 and less than or equal to 32, replacing excluded points with -1.

band_avg, band_no=[1,3], min=0, max=32, replace=-1, /geo

Arguments/Keywords:

band_no An array containing the numbers of the two loaded bands to difference. Relative to 1. (required)

geo Convert the two input bands to geophysical data values before differencing. The resultant output array will be stored in floating point values in terms of geophysical data values. Thus, the raw to geophysical scaling conversion variables: slope, intercept and scaling type will be set to 1.0, 0.0 and 'linear' respectively. (Default)

raw Difference in terms of raw data values. In differencing, it will probably not make sense to use this option. Floating-point operations will be performed on the raw data. The resultant grid will then be stored in the raw data type and the raw to geophysical scaling conversion variables: slope, intercept and scaling type will be copied from the first input array. If values in the resultant grid fall outside the possible range for the raw data type, then they will be assigned to the min or max possible values respectively.

min Only values greater than or equal to this value will be used when computing the difference. These values should be specified in terms of either raw or geophysical data values, depending on whether the user has specified the /raw or /geo keywords.

max Only values less than or equal to this value will be used when computing the difference. These values should be specified in terms of either raw or geophysical data values, depending on whether the user has specified the /raw or /geo keywords.

ignore Data values to ignore when computing the difference. These values should be specified in terms of either raw or geophysical data values, depending on whether the user has specified the /raw or /geo keywords.

tol A tolerance value to use in applying the ignore value. (Default 0.0)

replace The replace keyword is only applicable when either min/max or ignore exclusion criteria are set. This is the value which will be used in the resultant output array wherever valid calculations have not taken place. (Default for min/max exclusion is min-1 if min is set or max+1 if only max is set; Default for Ignore/Tolerance exclusion is the ignore value)

inclusive The inclusive keyword is only applicable when either min/max or ignore exclusion criteria are set. Inclusive means to only perform the calculation where both input values are valid (i.e. non-excluded) values. (Default)

exclusive This keyword is only applicable when either min/max or ignore exclusion criteria are set. Exclusive means that only one valid (i.e. non-excluded) value is required in order to perform the difference function.

err Pass back an error status. 0 = no error. Non-zero = an error occurred.

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band_no	An array containing the numbers of the two loaded bands to difference. Relative to 1. (required)
geo	Convert the two input bands to geophysical data values before differencing. The resultant output array will be stored in floating point values in terms of geophysical data values. Thus, the raw to geophysical scaling conversion variables: slope, intercept and scaling type will be set to 1.0, 0.0 and 'linear' respectively. (Default)
raw	Difference in terms of raw data values. In differencing, it will probably not make sense to use this option. Floating-point operations will be performed on the raw data. The resultant grid will then be stored in the raw data type and the raw to geophysical scaling conversion variables: slope, intercept and scaling type will be copied from the first input array. If values in the resultant grid fall outside the possible range for the raw data type, then they will be assigned to the min or max possible values respectively.
min	Only values greater than or equal to this value will be used when computing the difference. These values should be specified in terms of either raw or geophysical data values, depending on whether the user has specified the /raw or /geo keywords.
max	Only values less than or equal to this value will be used when computing the difference. These values should be specified in terms of either raw or geophysical data values, depending on whether the user has specified the /raw or /geo keywords.
ignore	Data values to ignore when computing the difference. These values should be specified in terms of either raw or geophysical data values, depending on whether the user has specified the /raw or /geo keywords.
tol	A tolerance value to use in applying the ignore value. (Default 0.0)
replace	The replace keyword is only applicable when either min/max or ignore exclusion criteria are set. This is the value which will be used in the resultant output array wherever valid calculations have not taken place. (Default for min/max exclusion is min-1 if min is set or max+1 if only max is set; Default for Ignore/Tolerance exclusion is the ignore value)
inclusive	The inclusive keyword is only applicable when either min/max or ignore exclusion criteria are set. Inclusive means to only perform the calculation where both input values are valid (i.e. non-excluded) values. (Default)
exclusive	This keyword is only applicable when either min/max or ignore exclusion criteria are set. Exclusive means that only one valid (i.e. non-excluded) value is required in order to perform the difference function.
err	Pass back an error status. 0 = no error. Non-zero = an error occurred.