This is a reference to a raster object.
Example
The following code opens a file which returns an ENVIRaster and then creates a new ENVIRaster with one band from the original raster.
e = ENVI()
file = FILEPATH('qb_boulder_msi', ROOT_DIR=e.ROOT_DIR, $
SUBDIRECTORY = ['data'])
raster = e.OpenRaster(file)
PRINT, raster
newFile = e.GetTemporaryFilename()
origData = EDGE_DOG(raster.GetData(BANDS=0))
newRaster = ENVIRaster(origData, URI=newFile, NBANDS=1)
newRaster.Save
view = e.GetView()
layer = view.CreateLayer(newRaster)
The next example shows how to create a new classification raster and add classification metadata to it:
e = ENVI()
File = e.GetTemporaryFilename()
data = Make_Array(500,500,value=0,/byte)
data[0:250,0:250] = 1
data[0:250,251:499] = 2
data[251:499,251:499] = 3
Metadata = ENVIRasterMetadata()
Metadata.AddItem, 'classes', 4
Metadata.AddItem, 'class names', ['Unclassified', 'Water', 'Vegetation','Soil']
Metadata.AddItem, 'class lookup', $
[[!Color.Black], [!Color.Blue], [!Color.Green],[!Color.Brown]]
Raster = ENVIRaster(data, URI=File, METADATA=Metadata)
Raster.Save
View = e.GetView()
Layer = view.CreateLayer(Raster)
Syntax
Result = ENVIRaster([, Data] [, Keywords=value] [, Properties=value])
Return Value
This function returns a reference to an ENVIRaster object.
Arguments
Data
A 2D or 3D array of data. When the Data argument is a 3D array, use the INTERLEAVE keyword to specify the interleave of the raster.
If you specify the Data argument, the values for the NBANDS, NCOLUMNS, NROWS, and DATA_TYPE properties are taken from the Data raster object. INTERLEAVE is assumed to be 'bsq' if not set.
You cannot create or modify an ENVIRaster that contains complex data.
If you do not specify the Data argument:
- An empty ENVIRaster object is created. You must specify (1) INHERITS_FROM or (2) NBANDS, NCOLUMNS, NROWS, and DATA_TYPE. You can then use ENVIRaster::SetData or ENVIRaster::SetTile to add data to the ENVIRaster.
- The NBANDS, NCOLUMNS, NROWS, and DATA_TYPE properties have precedence over the values in the INHERITS_FROM raster, if you specify that raster.
Methods
Close
CreatePyramid
CreateTileIterator
Dehydrate
Export
ExportROIs
GetData
Hydrate
Save
SetData
SetTile
WriteMetadata
Keywords
DATA_IGNORE_VALUE
Set this keyword to a pixel value that will be ignored when the raster is displayed. This overrides any data ignore values set in the metadata.
ERROR
Set this keyword to a named variable that will contain any error message issued during execution of this routine. If no error occurs, the ERROR variable will be set to a null string (''). If an error occurs and the routine is a function, then the function result will be undefined.
When this keyword is not set and an error occurs, ENVI returns to the caller and execution halts. In this case, the error message is contained within !ERROR_STATE and can be caught using IDL's CATCH routine. See IDL Help for more information on !ERROR_STATE and CATCH.
See Manage Errors for more information on error handling in ENVI programming.
INHERITS_FROM
Set this keyword to an ENVIRaster from which all metadata and the following properties will be copied: DATA_TYPE, INTERLEAVE, NBANDS, NCOLUMNS, and NROWS.
Data acquisition time (from the ENVIRaster TIME property) will not be copied.
Since new rasters are often created as the output of processing an input raster, they typically have the same spatial and spectral dimensions, interleave, and data type as the input raster. The INHERITS_FROM keyword provides convenience in inheriting these properties.
If you do not specify the INHERITS_FROM keyword, you must either provide the Data argument and INTERLEAVE is assumed to be 'bsq' if not set, or specify the NBANDS, NCOLUMNS, NROWS, and DATA_TYPE properties.
The NBANDS, NCOLUMNS, NROWS, and DATA_TYPE properties have precedence over the values in the INHERITS_FROM raster.
See ENVIRasterMetadata for details on creating and modifying metadata.
Note: If both the SPATIALREF and INHERITS_FROM keywords are specified, the spatial reference information from SPATIALREF takes precedence.
Properties
Properties marked as (Init) can be set during the initial creation of the object. Properties marked as (Get) can be retrieved. Properties marked as (Set) can be set after initial creation.
AUXILIARY_SPATIALREF (Get)
This property retrieves a reference to an ENVIGLTRasterSpatialRef, ENVIPseudoRasterSpatialRef, ENVIRPCRasterSpatialRef, or ENVIStandardRasterSpatialRef object, depending on what secondary map information the raster object uses for spatial reference (if any). This property provides a simple way to view secondary map information without having to query the metadata in the file header.
- If the raster object only has one spatial reference, this property returns a !NULL value.
- If the raster object contains standard map information plus RPC or pseudo information, the standard map information will be used as the primary spatial reference (returned by the SPATIALREF property) and the RPC or pseudo information will be the auxiliary spatial reference (returned by the AUXILIARY_SPATIALREF property). RPC information will be written to the header file (for ENVI-format files) if you call ENVIRaster::WriteMetadata.
- If the raster object contains RPC and pseudo map information, the RPC information will be used as the primary spatial reference (returned by the SPATIALREF property).
AUXILIARY_URI (Get)
This property retrieves a string array containing the URIs for any auxiliary files associated with the raster file. Auxiliary files are files that ENVI creates, specifically header and pyramid files. If there are no associated files, !NULL is returned.
COORD_SYS (Get)
This property retrieves a reference to the ENVICoordSys associated with the raster.
DATA_TYPE (Init, Get)
An integer or string specifying the raster data type (strings are not case-sensitive). When retrieving the property, a string is returned.
String |
Value |
Data Type |
byte |
1 |
Byte (8 bits) |
double |
5 |
Double-precision floating point (64 bits) |
float |
4 |
Floating point (32 bits) |
int |
2 |
Integer (16 bits) |
long |
3 |
Long integer (32 bits) |
uint |
12 |
Unsigned integer (16 bits) |
ulong |
13 |
Unsigned long integer (32 bits) |
You cannot create or modify an ENVIRaster that contains complex data.
INTERLEAVE (Init, Get)
A string specifying the interleave of the raster.
String |
Interleave |
Data Array |
bil |
Band interleaved by line |
[ncolumns, nbands, nrows] |
bip |
Band interleaved by pixel |
[nbands, ncolumns, nrows] |
bsq |
Band sequential |
[ncolumns, nrows, nbands] |
METADATA (Init, Get)
This property retrieves a reference to the ENVIRasterMetadata object. If METADATA and INHERITS_FROM are both set, the new raster will have the union of both sets of metadata. The METADATA values override those from INHERITS_FROM if there is a conflict.
MODALITY (Get)
A string specifying the type (category) of the raster. Possible values are Optical, Radar, DEM, and Thermal. ENVI extracts this property based on the value of the sensor type metadata. If sensor type is not set, modality will be an empty string.
NBANDS (Init, Get)
The number of bands in the raster.
NCOLUMNS (Init, Get)
The number of columns in the raster.
NROWS (Init, Get)
The number of rows in the raster.
PYRAMID_EXISTS (Get)
Returns 1 (TRUE) if a pyramid file exists for the raster, and 0 (FALSE) if not.
READ_ONLY (Get)
Returns 1 (TRUE) if ENVIRaster is read-only, and 0 (FALSE) if not. If the value is 0, the SetData and Save methods are available.
SPATIALREF (Init, Get)
This property retrieves a reference to an ENVIGLTRasterSpatialRef, ENVIPseudoRasterSpatialRef, ENVIRPCRasterSpatialRef, or ENVIStandardRasterSpatialRef object.
TIME (Init, Get)
This property retrieves a reference to the ENVITime object.
URI (Init, Get)
A string that is a fully qualified raster file path. If not set on initialization, a temporary file will be generated.
Version History
ENVI 5 |
Introduced |
ENVI 5.0.2 |
Added TIME property
|
ENVI 5.1 |
Added ability for ENVIRaster to serve as a constructor function for creating new raster objects. Added INHERITS_FROM keyword. Added Subset and Export methods.
|
ENVI 5.2 |
Deprecated Subset method. See ENVISubsetRaster.
|
ENVI 5.3 |
Added DATA_IGNORE_VALUE keyword
|
ENVI 5.4 |
Added Hydrate method
|
ENVI 5.5.1 |
Added COORD_SYS property
|
ENVI 6.1 |
Added MODALITY property
|
API Version
4.3
See Also
ENVI::OpenRaster, ENVIView::CreateLayer, ENVISubsetRaster