SeaDAS Arithmetic Band Functions Widget

Arithmetic Band Functions: band_diff, band_mean, band_sum

Description: The Arithmetic Band Functions provide a few simple arithmetic functions on any bands loaded into the display program:

Difference
Simple Mean
General Summation:

result = C + SUM[W(n)*I(n)**E(n)] for 1 to n,

where I=set of n input arrays, C=constant, W=weights, E=exponents

more robust mean function
add, subtract, multiple or perform exponentiation function on a single grid

The new resultant array will be added to the list of loaded bands as the next available band number and can be subsequently used as any other loaded product. The navigation information will be copied from the first input band. See the individual functions concerning the implications of performing calculations on the raw versus the geophysical data values.

Note: The general display program, seadisp must first be started and bands must be loaded before using the arithmetic band functions.

[Interactive Mode]

[Command Mode - Differencing: band_diff]

[Command Mode - Averaging: band_avg]

[Command Mode - General Summation: band_sum]

Interactive Mode:

Arithmetic Band Functions Widget: This widget can be accessed within the Main Menu by selecting Utilities->Data Manipulation->Arithmetic Band Functions.

Functions:

Simple Difference When the simple difference function is selected, options are displayed which are used for the difference function only. (see Simple Difference Options Widget)

Simple Mean When the simple mean function is selected, options are displayed which are used for the mean function only. (see Simple Mean Options Widget)

General Summation When the general summation function is selected, options are displayed for this function. (see General Summation Options Widget).

Simple Difference Options Widget:

Action/Info items:

Select input from available band list The list of data grids that have been loaded into memory and are available for use. To select either of the two input bands, I1 or I2, click on an item in the list. This list automatically updates whenever a new grid is added to or deleted from the Band List Selection Widget.

Function: I1 - I2 Describes the function as subtracting Input 2 from Input 1.

Specify Inputs

I1 Press the I1 button in order to specify the first input for subtraction. Select this input band by clicking an item in the Select input from available band list.

I2 Press the I2 button in order to specify the input to be subtracted from I1. Select this input band by clicking and item in the Select input from available band list.

Data Type A toggle to specify whether to perform the difference on the raw data or the geophysical data. See Command Mode for details.

Exclusion Method A toggle to choose between a Minimum/Maximum or Ignore/Tolerance method for excluding data when computing the difference.

Minimum value Only values greater than or equal to this value will be used when computing the difference. This value should be in terms of the same data values specified in Data Type.

Maximum value Only values less than or equal to this value will be used when computing the difference. This value should be in terms of the same data values specified in Data Type.

Ignore values Value(s) to ignore when computing the difference. This value should be in terms of the same data values specified in Data Type. Separate the values with commas.

Ignore tolerance A tolerance for the ignore value(s). (Default is 0.0)

Replace value The value to insert in the output array at the locations where the difference calculation was not performed. (Default for Minimum/Maximum exclusion is Minimum-1 if Minimum is specified or Maximum+1 if only Maximum is specified; Default for Ignore/Tolerance exclusion is the ignore value)

Calculate Inclusive Calculate the difference only where both input points are valid (i.e. non-excluded values). (Default)

Calculate Exclusive Calculate the difference if either one of the input points is valid (i.e. a non-excluded value).

Quit Exit the widget.

Help Bring up hypertext help in an HTML viewer.

Go Perform the difference function on the two loaded bands specified in I1 and I2. Notice that a new resultant output grid will appear in the Band List Selection Widget and is now available for use as any other loaded product.

Simple Mean Options Widget:

Action/Info items:

Select input from available band list The list of data grids that have been loaded into memory and are available for use. Click on an item in the list to select a band to be included for averaging. This list automatically updates whenever a new grid is added to or deleted from the Band List Selection Widget.

Select All This is a shorthand method to include all loaded bands for averaging.

Function: SUM[I(n)]/n for 1 to n Describes the function as being the mean grid of n input grids.

N=x This label is dynamically updated. It represents the current number of input grids to the mean function.

I=Inputs for Computing Mean The list of bands currently selected for performing the mean function.

Delete Delete the highlighted item from the inputs list.

Delete All Clear all items from the list of bands currently selected for calculating the mean.

Data Type A toggle to specify whether to perform the mean on the raw data or the geophysical data. See Command Mode for details.

Exclusion Method A toggle to choose between a Minimum/Maximum or Ignore/Tolerance method for excluding data when computing the mean.

Minimum value Only values greater than or equal to this value will be used when computing the mean. This value should be in terms of the same data values specified in Data Type.

Maximum value Only values less than or equal to this value will be used when computing the mean. This value should be in terms of the same data values specified in Data Type.

Ignore values Value(s) to ignore when computing the mean. This value should be in terms of the same data values specified in Data Type. Separate the values with commas.

Ignore tolerance A tolerance for the ignore value(s). (Default is 0.0)

Replace value The value to insert in the output array at the locations where the mean calculation was not performed. (Default for Minimum/Maximum exclusion is Minimum-1 if Minimum is specified or Maximum+1 if only Maximum is specified; Default for Ignore/Tolerance exclusion is the ignore value)

Calculate Inclusive Calculate the mean only where both input points are valid (i.e. non-excluded values).

Calculate Exclusive Calculate the mean if either one of the input points is valid (i.e. a non-excluded value). (Default)

Quit Exit the widget.

Help Bring up hypertext help in an HTML viewer.

Go Perform the mean function on the bands specified in Inputs for Computing Mean. Notice that a new resultant output grid will appear in the Band List Selection Widget and is now available for use as any other loaded product.

General Summation Options Widget:

Action/Info items:

Select input from available band list The list of data grids that have been loaded into memory and are available for use. Click on an item in the list to select a band to be included for summation. This list automatically updates whenever a new grid is added to or deleted from the Band List Selection Widget.

Select All This is a shorthand method to include all loaded bands for summation.

Function: C + SUM[W(n)*I(n)**E(n)]
for 1 to n Describes the function as being a general summation function on a series of n input grids. The output is a new grid. All variables in the above equation are described below.

N=x This label is dynamically updated. It represents the current number of input grids to the general summation function.

C=Constant This is a scalar constant to be added to every element of the resultant grid after the summation has been performed.

I=Inputs Grids, W=Weight, E=Exponent The list of bands currently selected for performing the general summation function, as well as the default weights (W) and exponents (E) for each band. The specified weight and exponent will be applied to each element of the corresponding input grid during summation.

Delete Delete the highlighted item from the input list.

Delete All Delete all items from the input list.

Update Update the values entered in the Weight and Exponent fields, into the current highlighted item in the input list.

Update All Update the values entered in the Weight and Exponent fields, into all of the items in the input list.

Weight The weight of the currently highlighted input band will appear here. To modify a weight value, enter a new weight in this field and then press either Update or Update All.

Exponent The exponent of the currently highlighted input band will appear here. To modify an exponent value, enter a new exponent in this field and then press either Update or Update All.

Data Type A toggle to specify whether to perform the summation on the raw data or the geophysical data. See Command Mode for more details.

Exclusion Method A toggle to choose between a Minimum/Maximum or Ignore/Tolerance method for excluding data when computing the summation.

Minimum value Only values greater than or equal to this value will be used when computing the summation. This value should be in terms of the same data values specified in Data Type.

Maximum value Only values less than or equal to this value will be used when computing the summation. This value should be in terms of the same data values specified in Data Type.

Ignore values Value(s) to ignore when computing the summation at every point. This value should be in terms of the same data values specified in Data Type. Separate the values with commas.

Ignore tolerance A tolerance for the ignore value(s). (Default is 0.0)

Replace value The value to insert in the output array at the locations where the summation calculation was not performed. (Default for Minimum/Maximum exclusion is Minimum-1 if Minimum is specified or Maximum+1 if only Maximum is specified; Default for Ignore/Tolerance exclusion is the ignore value)

Calculate Inclusive Calculate the summation only where both input points are valid (i.e. non-excluded values).

Calculate Exclusive Calculate the summation if either one of the input points is valid (i.e. a non-excluded value). (Default)

Quit Exit the widget.

Help Bring up hypertext help in an HTML viewer.

Go Perform the general summation function on the bands specified in I=Input Grids. Notice that a new resultant output grid will appear in the Band List Selection Widget and is now available for use as any other loaded product.

Curator: OceanColor Webmaster

Authorized by: gene carl feldman

Simple Difference	When the simple difference function is selected, options are displayed which are used for the difference function only. (see Simple Difference Options Widget)
Simple Mean	When the simple mean function is selected, options are displayed which are used for the mean function only. (see Simple Mean Options Widget)
General Summation	When the general summation function is selected, options are displayed for this function. (see General Summation Options Widget).

Select input from available band list	The list of data grids that have been loaded into memory and are available for use. Click on an item in the list to select a band to be included for averaging. This list automatically updates whenever a new grid is added to or deleted from the Band List Selection Widget.
Select All	This is a shorthand method to include all loaded bands for averaging.
Function: SUM[I(n)]/n for 1 to n	Describes the function as being the mean grid of n input grids.
N=x	This label is dynamically updated. It represents the current number of input grids to the mean function.
I=Inputs for Computing Mean	The list of bands currently selected for performing the mean function.
Delete	Delete the highlighted item from the inputs list.
Delete All	Clear all items from the list of bands currently selected for calculating the mean.
Data Type	A toggle to specify whether to perform the mean on the raw data or the geophysical data. See Command Mode for details.
Exclusion Method	A toggle to choose between a Minimum/Maximum or Ignore/Tolerance method for excluding data when computing the mean.
Minimum value	Only values greater than or equal to this value will be used when computing the mean. This value should be in terms of the same data values specified in Data Type.
Maximum value	Only values less than or equal to this value will be used when computing the mean. This value should be in terms of the same data values specified in Data Type.
Ignore values	Value(s) to ignore when computing the mean. This value should be in terms of the same data values specified in Data Type. Separate the values with commas.
Ignore tolerance	A tolerance for the ignore value(s). (Default is 0.0)
Replace value	The value to insert in the output array at the locations where the mean calculation was not performed. (Default for Minimum/Maximum exclusion is Minimum-1 if Minimum is specified or Maximum+1 if only Maximum is specified; Default for Ignore/Tolerance exclusion is the ignore value)
Calculate Inclusive	Calculate the mean only where both input points are valid (i.e. non-excluded values).
Calculate Exclusive	Calculate the mean if either one of the input points is valid (i.e. a non-excluded value). (Default)
Quit	Exit the widget.
Help	Bring up hypertext help in an HTML viewer.
Go	Perform the mean function on the bands specified in Inputs for Computing Mean. Notice that a new resultant output grid will appear in the Band List Selection Widget and is now available for use as any other loaded product.