IMAGELG2

Description

Finds the natural logarithm values in image channels, between two image files or within one image file.

Parameters

imagelg2(fili, filo, dbic, dboc, emptyvl)

Name	Type	Caption	Length	Value range
FILI *	str	Input file name	1 -
FILO	str	Output file name	0 -
DBIC *	List[int]	Input raster channel(s)	1 -
DBOC	List[int]	Output raster channel(s)	0 -
EMPTYVL	List[float]	Replacement for invalid numeric value	0 - 1	0.0 - 100000.0 Default: 0.0

* Required parameter

Parameter descriptions

FILI

Specifies the name of the PCIDSK file from which image data is to be converted to natural logarithm values.

FILO

Specifies the name of the output file to receive the natural logarithm of the input image channels.

If the specified output file does not exist, a new PCIDSK file is created. By default, the georeferencing information from the input is copied to the new output file.

DBIC

Specifies the input raster channel(s) to be processed.

DBOC

Specifies the output image channel(s) produced by taking the natural logarithm of the input image channel(s) (DBIC).

If the output file (FILO) does not already exist, this parameter should be empty.

Duplicate output channels are NOT allowed. The total number of input channels (DBIC) must be equal to the total number of output channels (DBOC).

Output channels must be 32-bit real.

EMPTYVL

Specifies the number used as replacement for invalid numerical values.

The default value is 0.0.

Details

IMAGELG2 takes all the pixel values from the input channel(s) and calculates the natural logarithm value, placing those values in the output channel(s). If an invalid value exists, the value specified in the Replacement Value (EMPTYVL) parameter is used instead.

The output channel(s) must be 32-bit real.

Example

Calculate natural logarithm values for channels 1 to 5 of irvine.pix.

from pci.imagelg2 import imagelg2

fili	=	"irvine.pix"	# input file
filo	=	"orvine.pix"	# output file (will be created)
dbic	=	list(range(1, 5 + 1))	# input channels
dboc	=	[]	# five 32R channels will be created
emptyvl	=	[]	# use default of 0.0

imagelg2( fili, filo, dbic, dboc, emptyvl )