ENVIRasterSeries::Previous

This method steps to the previous raster in the series. If the current raster is the first one in the series, the Previous method steps to the last one. Use this method to retrieve data from the previous raster, regardless of the current location within in the series.

Example

; Start the application

e = ENVI(/HEADLESS)

; Locate a raster series file

seriesFile = Filepath('AirTemp.series', Subdir=['data','time_series'], $

  Root_Dir = e.Root_Dir)

; Create a raster series object

series = ENVIRasterSeries(seriesFile)

; Print the contents of the series file

PRINT, series

; Set the current raster to be the beginning

; of 31 December (Index #8)

series.Set, 8

; Step to the previous raster in the series

series.Previous

; Close the raster

series.Close

Syntax

ENVIRasterSeries.Previous [, ERROR=variable]

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 5.2

Introduced

API Version

4.3