ENVIRasterMetadata::HasTag

The HasTag function method checks if a specified metadata field exists.

Example

PRO SetDataIgnoreValue

COMPILE_OPT IDL2

  ; Launch the application

  e = ENVI()

  ; Create an ENVIRaster

  file = FILEPATH('qb_boulder_msi', ROOT_DIR=e.ROOT_DIR, $

    SUBDIRECTORY = ['data'])

  raster = e.OpenRaster(file)

  ; Check if the metadata contains a data ignore

  ; value field. If so, update it. If not, add it.

  metadata = raster.METADATA

  IF (metadata.HasTag ('data ignore value')) THEN BEGIN

    metadata.UpdateItem, 'data ignore value', 0.0

  ENDIF ELSE BEGIN

    metadata.AddItem, 'data ignore value', 0.0

  ENDELSE

  ; Create a scratch output file

  newFile = e.GetTemporaryFilename()

  ; Export to a new file and update the header

  raster.Export, newFile, 'envi'

  ; Open the ENVI file

  raster1 = e.OpenRaster(newFile)

  view = e.GetView()

  layer = view.CreateLayer(raster1)

END

Syntax

Result = ENVIRasterMetadata.HasTag(Tag, [, ERROR=variable])

Arguments

Tag

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).

Keywords

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

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.

Version History

ENVI 5.3.1

Introduced

API Version

4.2