ColorSliceClassification Task

This task creates a classification raster by thresholding on select data ranges and colors to highlight areas of a raster. The default behavior is to create 16 classes from distinct colors spread across the "Rainbow" color table.

Example

This example uses the default property settings:

; 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 task from the catalog of ENVITasks

Task = ENVITask('ColorSliceClassification')

; Define inputs

Task.INPUT_RASTER = Raster

; 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)

See More Examples.

Syntax

Result = ENVITask('ColorSliceClassification')

Input properties (Set, Get): CLASS_COLORS, CLASS_RANGES, COLOR_TABLE_NAME, DATA_MAXIMUM, DATA_MINIMUM, INPUT_RASTER, NUMBER_OF_RANGES, RANGE_SIZE, REVERSE_COLOR_TABLE, OUTPUT_RASTER_URI

Output properties (Get only): OUTPUT_RASTER

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

Methods

This task inherits the following methods from ENVITask:

Properties

This task inherits the following properties from ENVITask:

COMMUTE_ON_DOWNSAMPLE

CLASS_COLORS (optional)

Specify a (3,n) byte array with the RGB colors for the given ranges, where n is the number of classes:

CLASS_COLORS = [[255,0,0], [0,0,200], [0,200,0]]

Or, specify IDL color names:

CLASS_COLORS = [[!color.red], [!color.blue], [!color.green]]

Use this property in conjunction with CLASS_RANGES.

CLASS_NAMES (optional)

Specify an array with the names for the given ranges.

CLASS_RANGES (optional)

Specify a (2,n) array of color slice ranges, where n is the number of classes. In each array element, specify the minimum and maximum data value for the class.

COLOR_TABLE_NAME (optional)

Specify a string with the name of an IDL color table. The default value is Rainbow. Issue the following command to find valid strings:

LOADCT, get_name=color_table_names

DATA_MAXIMUM (optional)

Specify the maximum value used calculate data ranges with NUMBER_OF_RANGES. If this is not set, then the largest value in the INPUT_RASTER band is used.

DATA_MINIMUM (optional)

Specify the minimum value used to calculate data ranges with NUMBER_OF_RANGES or RANGE_SIZE. If this is not set, then the smallest value in the INPUT_RASTER band is used.

INPUT_RASTER (required)

Specify a 1-band raster on which to perform color slice classification.

NUMBER_OF_RANGES (optional)

Specify the number of data ranges to create. If RANGE_SIZE is specified, then the ranges are each that width, starting at DATA_MINIMUM and ending at (DATA_MINIMUM+NUMBER_OF_RANGES*RANGE_SIZE). If RANGE_SIZE is not specified, then the ranges are equal width between DATA_MINIMUM and DATA_MAXIMUM.

OUTPUT_RASTER

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

OUTPUT_RASTER_URI (optional)

Specify a string with the fully qualified filename and path of the associated OUTPUT_RASTER. If you do not specify this property, or set it to an exclamation symbol (!), a temporary file will be created.

RANGE_SIZE (optional)

Specify the width of each data range to create. The NUMBER_OF_RANGES is used in conjunction with RANGE_SIZE. Any data above DATA_MINIMUM+NUMBER_OF_RANGES*RANGE_SIZE will not be classified.

REVERSE_COLOR_TABLE (optional)

Set this property to reverse the color table. Use this property in conjunction with COLOR_TABLE_NAME property. The options are true or false.

More Examples

This example shows the use of CLASS_COLORS and CLASS_RANGES:

; 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)

; Process a spatial subset

Subset = ENVISubsetRaster(Raster, BANDS=0)

Class_Ranges = [[200,300],$

  [300,400],$

  [600,700], $

  [700,800],$

  [1000,1100]]

Class_Colors = [[255,0,0], $

  [0,0,200], $

  [0,200,0], $

  [128,128,0], $

  [0,128,128]]

; Get the task from the catalog of ENVITasks

Task = ENVITask('ColorSliceClassification')

; Define inputs

Task.INPUT_RASTER = Subset

Task.CLASS_RANGES = Class_Ranges

Task.CLASS_COLORS = Class_Colors

; Define outputs

Task.OUTPUT_RASTER_URI = e.GetTemporaryFilename()

; 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

View1 = e.GetView()

Layer1 = View1.CreateLayer(Task.Output_Raster)

The next example shows the use of DATA_MINIMUM, DATA_MAXIMUM, and NUMBER_OF_RANGES.

; 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)

; Process a spatial subset

Subset = ENVISubsetRaster(Raster, BANDS=3)

; Get the task from the catalog of ENVITasks

Task = ENVITask('ColorSliceClassification')

; Define inputs

Task.INPUT_RASTER = Subset

Task.DATA_MINIMUM = 178

Task.DATA_MAXIMUM = 676

Task.NUMBER_OF_RANGES = 5

; Define outputs

Task.OUTPUT_RASTER_URI = e.GetTemporaryFilename()

; 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

View1 = e.GetView()

Layer1 = View1.CreateLayer(Task.Output_Raster)

Version History

ENVI 5.2

Introduced

API Version

4.2