ENVIRasterSeriesLayer::Previous

This method moves the raster series layer to the previous frame. If the first frame is currently displayed, it loops to the last frame in the series.

Example

This example builds a spatiotemporal series from sample gridded data in the ENVI installation path. It creates a raster series layer, sets it to the frame associated with index #4, then loops to the previous frame in the series.

; Start the application

e = ENVI()

; 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)

; Create a view

View = e.GetView()

; Create a raster series layer

Layer = View.CreateLayer(series)

; Set the layer to the frame with index #4

; Indices are zero-based

Layer.Set, 3

; Loop to the previous frame

Layer.Previous

Syntax

ENVIRasterSeriesLayer.Previous [, ERROR=variable]

Keywords

ERROR (optional)

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.

NO_WAIT (optional)

By default, after executing the Previous method you cannot issue another command at the ENVI command line until the frame has finished loading into memory. For large datasets, this can take several seconds. Set the NO_WAIT keyword to allow the next command to execute without having to wait for the current frame to load.

Version History

ENVI 5.2

Introduced

API Version

4.2