UNLOCK

Description

Unlocks previously write-locked image channels in a PCIDSK image file so that other programs can write to these channels.

Parameters

unlock(file, dbic)

Name	Type	Caption	Length	Value range
FILE *	str	Input file name	1 -
DBIC	List[int]	Input raster channels	0 -	-1024 -

* Required parameter

Parameter descriptions

FILE

Specifies the name of the PCIDSK file which contains the image channels to unlock.

DBIC

Specifies the image channels to unlock.

If this parameter is not specified, all channels are unlocked.

Details

Unlocks previously write-locked image channels in a PCIDSK file so that other functions can write to these channels.

Image channels in PCIDSK files can be write-locked. Write-locked channels can be read but any attempt to write to or modify the contents is prevented. This generally means that write-locked channels can be used as input to any operation but cannot be output to. This is useful for protecting certain channels (for example, the original raw data or completed results) from being overwritten. The LOCK function write-locks specified channels; UNLOCK removes this protection, allowing channels to be overwritten.

Any PCIDSK file (FILE) containing imagery data can have specified image channels (DBIC) unlocked. If no channels are specified, all image channels are unlocked.

Example

Channels 1 through 6 and channel 10 on the file irvine.pix contain 'raw' data, and have been previously write-locked. Unlock channel 10.

from pci.unlock import unlock

file	=	'irvine.pix'
dbic	=	[10]

unlock( file, dbic )

Channel 10 can now be used to receive output results.