SpectralIndex Task
This task creates a spectral index raster from one pre-defined spectral index. Spectral indices are combinations of surface reflectance at two or more wavelengths that indicate relative abundance of features of interest.
Use the SpectralIndices task to create a raster with one or more bands, where each band represents a different spectral index.
The data-ignore value of the output raster is set to -1034.
The virtual raster associated with this task is ENVISpectralIndexRaster.
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 task from the catalog of ENVITasks
Task=ENVITask('SpectralIndex')
; Define inputs
Task.INDEX = 'Normalized Difference Vegetation Index'
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)
Syntax
Result = ENVITask('SpectralIndex')
Input properties (Set, Get): INDEX, INPUT_RASTER, 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:
This task also contains the following properties:
INDEX (required)
Specify a string representing the pre-defined spectral index to apply to the input raster:
- Alunite Index (ALUI)
- Anthocyanin Reflectance Index 1 (ARI1)
- Anthocyanin Reflectance Index 2 (ARI2)
- Atmospherically Resistant Vegetation Index (ARVI)
- Burn Area Index (BAI)
- Calcite Index (CALI)
- Carotenoid Reflectance Index 1 (CRI1)
- Carotenoid Reflectance Index 2 (CRI2)
- Cellulose Absorption Index (CAI)
- Clay Alteration Index (CLAI)
- Clay Minerals Ratio (CLAY)
- Difference Vegetation Index (DVI)
- Disease Water Stress Index (DWSI)
- Dolomite Index (DOLI)
- Enhanced Vegetation Index (EVI)
- Epidote / Chlorite / Amphibole Index (ECAI)
- Ferric Iron Alteration Index (FEAI)
- Ferrous Iron (Fe2+) Index (FEI)
- Ferrous Minerals Ratio (Ferrous)
- Ferrous Silicates Index (FESI)
- Global Environmental Monitoring Index (GEMI)
- Green Atmospherically Resistant Index (GARI)
- Green Chlorophyll Index (GCI)
- Green Difference Vegetation Index (GDVI)
- Green Leaf Index (GLI)
- Green Normalized Difference Vegetation Index (GNDVI)
- Green Optimized Soil Adjusted Vegetation Index (GOSAVI)
- Green Ratio Vegetation Index (GRVI)
- Green Soil Adjusted Vegetation Index (GSAVI)
- Green Vegetation Index (GVI)
- Hydroxyl-Bearing (OH) Altered Minerals Index 1 (OHI1)
- Hydroxyl-Bearing (OH) Altered Minerals Index 2 (OHI2)
- Hydroxyl-Bearing (OH) Altered Minerals Index 3 (OHI3)
- Infrared Percentage Vegetation Index (IPVI)
- Iron Oxide Ratio (Iron Oxide)
- Kaolinite Index 1 (KAI1)
- Kaolinite Index 2 (KAI2)
- Kaolinite Index 3 (KAI3)
- Laterite Index (LATI)
- Leaf Area Index (LAI)
- Leaf Chlorophyll Index (LCI)
- Leaf Water Vegetation Index 1 (LWVI1)
- Leaf Water Vegetation Index 2 (LWVI2)
- Lignin Cellulose Absorption Index (LCAI)
- Magnesite Index (MAGI)
- Methane Index (METHANE)
- MgOH-Carbonate Abundance Index (MGAI)
- Modified Chlorophyll Absorption Ratio Index (MCARI)
- Modified Chlorophyll Absorption Radio Index Improved (MCARI2)
- Modified Non-Linear Index (MNLI)
- Modified Normalized Difference Water Index (MNDWI)
- Modified Red Edge Normalized Difference Vegetation Index (MRENDVI)
- Modified Red Edge Simple Ratio (MRESR)
- Modified Simple Ratio (MSR)
- Modified Soil Adjusted Vegetation Index 2 (MSAVI2)
- Modified Triangular Vegetation Index (MTVI)
- Modified Triangular Vegetation Index - Improved (MTVI2)
- Moisture Stress Index (MSI)
- Montmorillonite Index (MONI)
- Muscovite Index (MUSI)
- Non-Linear Index (NLI)
- Normalized Burn Ratio (NBR)
- Normalized Difference Built-Up Index (NDBI)
- Normalized Difference Infrared Index (NDII)
- Normalized Difference Lignin Index (NDLI)
- Normalized Difference Mud Index (NDMI)
- Normalized Difference Nitrogen Index (NDNI)
- Normalized Difference Snow Index (NDSI)
- Normalized Difference Vegetation Index (NDVI)
- Normalized Difference Water Index (NDWI)
- Normalized Multiband Drought Index (NMDI)
- Normalized Pigment Chlorophyll Index (NPCI)
- Optimized Soil Adjusted Vegetation Index (OSAVI)
- Phengitic Index (PHEI)
- Photochemical Reflectance Index (PRI)
- Phyllic Alteration Index (PHAI)
- Plant Senescence Reflectance Index (PSRI)
- Propylitic Alteration Index (PRAI)
- Red Edge Normalized Difference Vegetation Index (RENDVI)
- Red Edge Position Index (REPI)
- Red Green Ratio Index (RGRI)
- Renormalized Difference Vegetation Index (RDVI)
- Silica Dioxide Index (SIDI)
- Simple Ratio (SR)
- Soil Adjusted Vegetation Index (SAVI)
- Structure Independent Pigment Index (SIPI1)
- Structure Insensitive Pigment Index (SIPI)
- Sum Green Index (SGI)
- Transformed Chlorophyll Absorption Reflectance Index (TCARI)
- Transformed Difference Vegetation Index (TDVI)
- Triangular Greenness (TGI)
- Triangular Vegetation Index (TVI)
- Visible Atmospherically Resistant Index (VARI)
- Water Band Index (WBI)
- Wide Dynamic Range Vegetation Index (WDRVI)
- WorldView Built-Up Index (WV-BI)
- WorldView Improved Vegetative Index (WV-VI)
- WorldView New Iron Index (WV-II)
- WorldView Non-Homogeneous Feature Difference (WV-NHFD)
- WorldView Soil Index (WV-SI)
- WorldView Water Index (WV-WI)
INPUT_RASTER (required)
Specify a raster from which to generate a spectral index raster.
OUTPUT_RASTER
This is a reference to the output raster of filetype ENVI.
The data ignore value is set to -10 34.
OUTPUT_RASTER_URI (optional)
Specify a string with the fully qualified filename and path to export the associated OUTPUT_RASTER.
- If you set this property to an asterisk symbol (*), the output raster will be virtual and not written to disk.
- If you do not specify this property, or set it to an exclamation symbol (!), a temporary file will be created.
Version History
|
ENVI 5.2 |
Introduced |
|
ENVI 5.5 |
OUTPUT_RASTER_URI now supports '*', which allows OUTPUT_RASTER to be virtual output. |
API Version
4.2
See Also
ENVITask, ENVISpectralIndicesTask, ENVISpectralIndexRaster, QuerySpectralIndices Task