THMRMER

Description

Creates a new thematic raster based on merging pixel values by attributes.

Parameters

thmrmer(fili, filo, dbic, dboc, adjshp, joindgl, attrlist)

Name	Type	Caption	Length	Value range
FILI *	str	Input file name	1 -
FILO	str	Output file name	0 -
DBIC *	List[int]	Input thematic raster channel	1 - 1
DBOC	List[int]	Output thematic raster channel	0 - 1
ADJSHP	str	Shape merging method	0 - 15	ADJACENT | ALL Default: ADJACENT
JOINDGL	str	Join polygons at diagonal	0 - 3	YES | NO Default: YES
ATTRLIST	str	Attribute names	0 - 660

* Required parameter

Parameter descriptions

FILI

Specifies the name of the PCIDSK file that contains the thematic raster image channel.

FILO

Specifies the name of the PCIDSK image file to receive the processed thematic raster channel. If the output file is not specified, it will be assumed to be the same as FILI. If the specified output file already exists, its projection must be the same as that of the input file.

If FILO is specified but does not already exist, a new PCIDSK file will be created. By default, the projection information from FILI will be copied to the new FILO.

DBIC

Specifies the input channel that contains the input raster or thematic raster.

DBOC

Specifies the output channel to receive the generated thematic raster.

If the specified output file (FILO) exists, this parameter must be specified.

ADJSHP

Specifies the method to use for merging shapes.

JOINDGL

Specifies whether to join polygons at diagonals.

ATTRLIST

Specifies the list of attributes to use for merging.

This parameter can list 10 attributes, separated by blank spaces.

Details

THMRMER merges classes within a thematic raster to create a new thematic raster with aggregated classes. The classes to be merged are based on the attribute(s) specified. For two classes to be merged, the value within the specified attribute(s) must be the same for those two classes. The location of the pixels that form the classes can also be taken into account, if desired. You can specify that only adjacent (neighboring) pixels are to be merged, or that all of the classes that are attribute matches should be merged.

For example, suppose you have detailed data at the county level for a whole country, but are only interested in information at the state/provincial level. If the county data has an attribute indicating the state/province to which it belongs, you can use THMRMER to aggregate the county classes together to a state/provincial level.

If you want more control over the attributes that you want in the output thematic raster, you can use the Dissolve tool in CATALYST Professional Focus.

Example

This example demonstrates the use of THMRMER to generate a thematic raster layer based on attributes.

from pci.thmrmer import thmrmer

fili	=	"thmrcover.pix"	# input file
filo	=	"output.pix"	# output file
dbic	=	[1]	# input thematic raster channel
dboc	=	[1]	# output channel
adjshp	=	"ADJACENT"	# adjacent shapes
joindgl	=	"YES"	# join at diagonal
attrlist	=	"Perimeter theme1"	# field names(attributes)

thmrmer( fili, filo, dbic, dboc, adjshp, joindgl, attrlist )