Quality Layer Generation module

Description

The Quality Layer Generation module creates per-pixel quality file and layers required to meet the CARD4L-SR product specification.

Parameters

Name	Caption
Input Scenes	Input scene folder
Output Folder	Output folder
Output File Type	Output file type
Output File Options	Output file options
Overwrite Results	Overwrite existing results
Send Email	Email notification settings
DEM Source	DEM tile source

Parameter descriptions

Input Scenes

The path and name of the folder containing multispectral (MS) images to process.

Output Folder

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

Output File Type

The format of the output file.

For more information on the supported file formats, see GDB-supported file formats.

Output File Options

The options to apply when creating the output file or files. The available options are specific to the file format; in each case, the default of no options is allowed.

For more information on the options available for the output file type you specify, see GDB-supported file formats.

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.

DEM Source

The name of a file or folder containing DEM tiles.

This value may be the name of a single DEM file, the name of a folder containing DEM tiles, or the name of an index.txt file.

If the name of an existing folder is specified, the module reads the folder for a file named index.txt, and a set of DEM raster tiles. The index.txt file lists the DEM files contained in the specified folder and provides information describing each raster tile.

For more information on the format of the index.txt file and specific requirements for the individual DEM tiles, see Format of the DEM index file.

Details

General job details

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

Input scenes must be multispectral (MS) images.
At a minimum red, green, and near infrared (NIR) bands must be available in the imagery.
The available number of bands determines the levels of classification applied for generating pixel quality layer.
A digital elevation model (DEM) is required for determining cast shadows. The specified DEM must be in a GDB-compatible format and should cover the full extents of the imagery. To ensure a highly accurate quality measurement, the DEM should be as accurate as possible. The DEM can be supplied as a single file, or a folder of individual DEMs.

Module details

Quality Layer Generation module creates a file containing multiple quality layers for different QA requirements. These quality layers are in a rasterized file format to satisfy the requirement for machine readability of metadata. The generated quality layers also meet the CARD4L standards from USGS.

A per-pixel level quality file is created for each input scene. It contains raster channels representing quality layers, as follows:

Pixel Quality Layer: contains the information required to determine whether or not a pixel is suitable for inclusion into a process
Solar and Viewing Geometry Layers: contains the solar and satellite viewing angles (zenith and azimuth) for every pixel

Job results

For each valid input scene, the Quality Layer Generation module creates a quality file contains quality layers (channels) computed from the input file. The name of the output image file is based on the name of the input image file. That is, the name of the output file is appended with QLTY to indicate it is a quality file; for example:

Input file:	2014-12-29T033054_RE3_1B-NAC_18998309_270548_RAW_MS.pix
Output file:	2014-12-29T033054_RE3_1B-NAC_18998309_270548_RAW_QLTY.pix

Input file:	51194180908010853222J.pix
Output file:	51194180908010853222J_QLTY.pix

You can open the processed scenes in CATALYST Professional Focus to perform quality assurance (QA).

The possible output classes within the QLTY image are as follows:

Class Name	Pixel Value
no data	0
clear	10
water	20
cloud shadow	30
terrain shadow	40
cloud	50
snow ice	60