Object Analyst Change Detection module

Description

The Object Analyst Change Detection module reads the input scenes folder for classified images to compare against a reference file containing classified polygons.

Parameters

Name	Caption
Input Scenes	Input scene folder
Output Folder	Output folder
Overwrite Results	Overwrite existing results
Send Email	Email notification settings
Operation	Change detection operation
Input Field Name	Input classification field
Input Class Name	Input classification attribute
Reference Vector File	Reference vector file
Use All Reference Polygons	Use all polygons in reference file
Reference Attributes Are the Same	Reference attributes are the same as the input attributes
Reference Field Name	Reference classification field
Reference Class Name	Reference classification attribute

Parameter descriptions

Input Scenes

The path and name of a folder containing classified scenes.

This parameter can be specified by using any of the following:

Path and name of a folder of input images; for example, C:\data
Path and name of a folder with a wildcard to filter the imagery by file name or type; for example, C:\data\*.pix
You can also specify an MFILE as input. An MFILE is a text file with an .mfile file name extension. For more information on this type of file, see About the MFILE format.

Output Folder

The path and name of the folder to which to write the output files.

Overwrite Results

Select this check box to overwrite the existing output files, if any exist. If this check box is left clear, and an output file exists in the relevant folder, the status of the job displays a message informing you of the existence and name of the output file. The message is also written to the event log of the job.

Send Email

If necessary, you can set up CATALYST Enterprise to send an email notification on job start and job completion.

With this check box selected, an email message is sent to each address specified in the Email Addresses box after the job starts and on completion.

You can specify one or more addresses, and each must be separated by a comma or a semi-colon. The email address of the user currently logged in displays by default.

Operation

Whether to detect new changes in the input images, or the reference file.

Available operations are:

Input - Reference: Detect new polygons in the input files.
Reference - Input: Detect new polygons in the reference files.

Input Field Name

The field name from the attribute tables of the Input Scenes to query for change detection.

The attribute table can be inspected in CATALYST Professional Focus.

Input Class Name

The class name from the attribute table to query under the field name specified by Input Field Name.

The attribute table can be inspected in CATALYST Professional Focus.

Reference Vector File

The path and name of a previously classified file to use as reference when comparing against input files.

A classified file can be created using Object Analyst in CATALYST Professional Focus. It can also be created using the Object Analyst Segmentation and Classification module.

Users may also pass an unclassified file, and use all polygons contained within the file.

Use All Reference Polygons

Select this check box to use all polygons from the Reference Vector File. If this check box is left clear, and Reference Attributes Are the Same is left clear, Reference Field Name and Reference Class Name must be specified.

Selecting this check box will allow vector files to be used that were not created using Object Analyst. For example, a national waterbody shapefile could be used.

Reference Attributes Are the Same

Selecting this check box will force the Reference Vector File to use the same Field Name and Class Name as the Input Scenes. If this check box is left clear, Reference Field Name and Reference Class Name must be specified.

Reference Field Name

The field name from the attribute table of the Reference Vector File to query for change detection.

The attribute table can be inspected in CATALYST Professional Focus.

Reference Class Name

The class name from the attribute table to query under the field name specified by Reference Field Name.

The attribute table can be inspected in CATALYST Professional Focus.

Details

General job details

Preprocessing requirements

Before running this module, the following requirements must be met to ensure the job processes successfully and produces accurate results:

Input Scenes: The Input Scenes folder must contain a series of .pix files that must each contain at least one polygon vector segment. It is recommended they are created using the Object Analyst Segmentation and Classification module or Object Analyst in CATALYST Professional Focus.
Reference Vector File: The Reference Vector File must contain a polygon vector segment. It is recommended that it is created using the Object Analyst Segmentation and Classification module or Object Analyst in CATALYST Professional Focus.

Module details

The Object Analyst Change Detection module automatically compares a series of classified files with a reference classified file. Any polygons that match the specified class names and exist in the input files, but not the reference file will be identified.

Job results

The results produced by the Object Analyst Change Detection module is one vector difference file for each input file. The differences are represented with polygons.