The AddItem method adds a user-defined metadata item.

For ENVI-format rasters, the following standard metadata tags are reserved and cannot be used with the AddItem method: bands, byte order, coordinate system string, data type, file type, geo points, header offset, interleave, lines, map info, pixel size, projection info, rpc info, and samples.

To save metadata changes to disk, use the ENVIRaster::WriteMetadata method.


; Launch the application
e = ENVI()
; Create an ENVIRaster
file = FILEPATH('qb_boulder_msi', ROOT_DIR=e.ROOT_DIR, $
  SUBDIRECTORY = ['data'])
raster = e.OpenRaster(file)
; Add the metadata tag default stretch
metadata = raster.METADATA
metadata.AddItem,'default stretch', '5.0% linear'
; Create a scratch output file
newFile = e.GetTemporaryFilename()
; Export to a new file with the default stretch metadata
raster.Export, newFile, 'envi'
; Open the ENVI file
raster1 = e.OpenRaster(newFile)
view = e.GetView()
layer = view.CreateLayer(raster1)


ENVIRasterMetadata.AddItem, Tag, Value [, ERROR=variable]



The tag name of the metadata item you wish to add. Metadata tags are defined by the file format from which the ENVIRaster was opened. Consult your data provider or file format specification for more information on metadata fields for specific sensors and/or data formats (GeoTIFF, NITF, and others).


The value of the metadata item you wish to add.

Note: User-defined metadata is stored in the header (.hdr) file as a string. An array is stored as a vector of strings.


Keywords are applied only during the initial creation of the object.


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.

Version History



API Version


See Also

ENVIRasterMetadata, ENVIRasterMetadata::HasTag, ENVIRasterMetadata::RemoveItem, ENVIRasterMetadata::UpdateItem, ENVIRaster's METADATA property, ENVIRaster::WriteMetadata