This task performs QUick Atmospheric Correction (QUAC) on multispectral or hyperspectral imagery. If you export the result to disk, the data ignore value is set to 0 in the corresponding header file.

The result consists of unsigned 2-byte integer reflectance data, scaled by 10,000.

This task requires a separate license for the ENVI Atmospheric Correction Module; contact your sales representative for more information.

The virtual raster associated with this task is ENVIQUACRaster.

Example


; Start the application
e = ENVI()
 
; Open an input file
File = Filepath('qb_boulder_msi', Subdir=['data'], $
   Root_Dir=e.Root_Dir)
Raster = e.OpenRaster(File)
 
; Get the QUAC task from the catalog of ENVITasks
Task = ENVITask('QUAC')
 
; Define inputs
Task.INPUT_RASTER = Raster
Task.SENSOR = 'QuickBird'
 
; Run the task
Task.Execute
 
; Get the collection of data objects currently available in the Data Manager
DataColl = e.Data
 
; Add the output to the Data Manager
DataColl.Add, Task.OUTPUT_RASTER
 
; Display the result
View = e.GetView()
Layer = View.CreateLayer(Task.OUTPUT_RASTER)
 

Syntax


Result = ENVITask ('QUAC')

Input parameters (Set, Get): INPUT_RASTER, SENSOR, OUTPUT_RASTER_URI

Output parameters (Get only): OUTPUT_RASTER

Parameters marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Parameters marked as "Get" are those whose values you can retrieve but not set.

Input Parameters


INPUT_RASTER (required)

Specify a raster on which to perform the atmospheric correction.

OUTPUT_RASTER_URI (optional)

Specify a string with the fully qualified filename and path to export the associated OUTPUT_RASTER.

  • If you set this parameter to an asterisk symbol (*), the output raster will be virtual and not written to disk.
  • If you do not specify this parameter, or set it to an exclamation symbol (!), a temporary file will be created.
  • If you set it to the hash symbol (#), ENVI creates a file in the temporary directory, but this file will not be deleted when ENVI closes.

SENSOR (optional)

Specify one of the following strings, indicating the sensor type of the input raster:

Generic / Unknown Sensor
Highly Vegetated Scenes
AISA-ES
ALI
ASAS
AVIRIS
CAP ARCHER
CASI
COMPASS
HYCAS
HYDICE
HyMap
Hyperion
Landsat TM/ETM/OLI
LASH
MARS
MODIS
QuickBird
RGB
WorldView-2
Near Infrared (NIR)
Near-Shortwave Infrared (NIR-SWIR)
  • If SENSOR is not set, then the task uses the Generic/Unknown Sensor option to guess the best sensor type, based on the number of input bands and their wavelengths.
  • Select the Highly Vegetated Scenes option if the image is highly vegetated.
  • Select the Near Infrared (NIR) option if the input raster has more than 70 bands and the wavelengths span the near-infrared region.
  • Select the Near-Shortwave Infrared (NIR-SWIR) option if the input raster has more than five bands and the wavelengths span the near-shortwave infrared region.

Output Parameters


OUTPUT_RASTER

This is a reference to the output raster of filetype ENVI.

Methods


Execute

Parameter

ParameterNames

Properties


DESCRIPTION

DISPLAY_NAME

NAME

REVISION

TAGS

Version History


ENVI 5.1

Introduced

ENVI 5.3

Updated baseline algorithm

ENVI 5.5

OUTPUT_RASTER_URI now supports '*', which allows OUTPUT_RASTER to be virtual output.

See Also


ENVITask, CalculateQUACGainOffset Task, ENVIQUACRaster, DarkSubtractionCorrection Task, FlatFieldCorrection Task, IARReflectanceCorrection Task, Masking Support in ENVITasks