BandMaths Operator

BandMaths Operator Description

Overview

Description

This band maths operator can be used to create a product with multiple bands based on mathematical expression.
All products specified as source must have the same width and height, otherwise the operator will fail. The geo-coding information and metadata for the target product is taken from the first source product.

To reference a band of one of the source products within an expression use the following syntax:

$sourceProduct.#.bandName

Where # means the index of the source product. The index is zero based.
The bands of the first source product ($sourceProduct.0) can be referenced without this product identifier. The band name is sufficient.

When using this operator from the command-line Graph XML file must be provided in order to specify all parameters. Here is some sample XML of how to use a BandMaths node within a graph:

      <node id="bandMathsNode">
        <operator>BandMaths</operator>
        <sources>
            <sourceProducts>readNode</sourceProducts>
        </sources>
        <parameters>
            <targetBands>
                <targetBand>
                    <name>reflec_13</name>
                    <expression>radiance_13 / (PI * SOLAR_FLUX_13)</expression>
                    <description>TOA reflectance in channel 13</description>
                    <type>float</type>
                    <validExpression>reflec_13 >= 0</validExpression>
                    <noDataValue>-999</noDataValue>
                    <spectralBandIndex>13</spectralBandIndex>
                </targetBand>
                <targetBand>
                    <name>reflec_14</name>
                    <expression>radiance_14 / (PI * SOLAR_FLUX_14)</expression>
                    <description>TOA reflectance in channel 14</description>
                    <type>float</type>
                    <validExpression>reflec_14 >= 0</validExpression>
                    <noDataValue>-999</noDataValue>
                    <spectralBandIndex>14</spectralBandIndex>
                </targetBand>
            </targetBands>
            <variables>
                <variable>
                    <name>SOLAR_FLUX_13</name>
                    <type>float</type>
                    <value>914.18945</value>
                </variable>
                <variable>
                    <name>SOLAR_FLUX_14</name>
                    <type>float</type>
                    <value>882.8275</value>
                </variable>
                 <variable>
                    <name>PI</name>
                    <type>double</type>
                    <value>3.1415</value>
                </variable>
            </variables>
        </parameters>
    </node>
 

Changes from version 1.0 to 1.1:

1. Added setter and getter methods for parameters
2. Changed type of BandDescriptor.noDataValue from String to Double
3. Deprecated API method 'createBooleanExpressionBand'

Sources

Parameters