Detect Change Using Change Analysis function

Available with Image Analyst license.

Overview

Generates a raster layer containing pixel change information using the output change analysis raster from the Analyze Changes Using CCDC tool.

For information about the CCDC method, see How Analyze Changes Using CCDC works.

Note:

This raster function only supports an input raster from the Analyze Changes Using CCDC tool, or it can be combined with the CCDC Analysis raster function in a raster function template. To produce a raster output, connect the CCDC Analysis function to the Detect Change Using Change Analysis function using the Function Editor, save as a raster function template, and use this as the input to theGenerate Raster From Raster Function tool.

Notes

The Change Type parameter indicates the information that will be generated. Information is extracted from the change analysis raster. There are four options:

• Time of Latest Change—The most recent date and time at which a pixel was flagged as changed.
• Time of Earliest Change—The earliest date and time at which a pixel was flagged as changed.
• Time of Largest Change—The date and time at which the calculated change was the most significant for a pixel.
• Number of Changes—The total number of times the pixel changed.

The output raster is a multiband raster in which each band contains change information depending on the change type selected and the maximum number of changes specified. For example, if Change Type is set to Time of Earliest Change and Maximum Number of Changes is set to 2, the function calculates the two earliest dates when change occurred throughout the time series for every pixel. The result is a raster in which the first band contains the dates of the earliest change per pixel, and the second band contains the dates of the second-earliest change per pixel.

Parameters

Parameter	Description
Raster	The input change analysis raster.
Change Type	Specifies the change information to calculate. Time of Latest Change—Each pixel will contain the date of the most recent change for that pixel in the time series. This is the default. Time of Earliest Change—Each pixel will contain the date of the earliest change for that pixel in the time series. Time of Largest Change—Each pixel will contain the date of the most significant change for that pixel in the time series. Number of Changes—Each pixel will contain the total number of times the pixel changed in the time series.
Maximum Number of Changes	The maximum number of changes per pixel that will be calculated when Change Type is set to Time of Latest Change, Time of Earliest Change, or Time of Largest Change. The number entered corresponds to the number of bands in the output raster. The default is 1, meaning only one change date will be calculated, and the output raster will contain only one band.