THMROVR

Description

Takes two or more thematic rasters, overlays them, and produces a new output thematic raster.

Parameters

thmrovr(fili, filo, dbic, dbib, dboc, omethod)

Name	Type	Caption	Length	Value range
FILI *	str	Input file name	1 -
FILO	str	Output file name	0 -
DBIC *	List[int]	Input raster channels	2 -
DBIB	List[int]	Input bitmap mask segment	0 - 1
DBOC	List[int]	Output thematic raster channel	0 - 1
OMETHOD	str	Overlay method	0 - 12	UNION \| INTERSECTION Default: UNION

* Required parameter

Parameter descriptions

FILI

Specifies the input PCIDSK file that contains the thematic rasters to overlay. All input thematic rasters must have the same projection/datum and pixel size.

FILO

Specifies the name of the PCIDSK image file to receive the output thematic raster, which is a combination of all of the input channels.

DBIC

Specifies the channels of thematic raster data to combine. At least two input raster channels must be specified.

All input thematic rasters must have the same projection/datum and pixel size.

DBIB

Specifies the segment that contains the input area mask, which indicates the area to process. Only the area under the bitmap will be processed. The bitmap must have the same projection/datum and pixel size as the input thematic rasters.

DBOC

Specifies the channel to receive the output thematic raster, which is a combination of all of the input channels.

OMETHOD

Specifies the method to use for the overlay processing.

Available options are:

UNION: union of input data. Overlays all the shapes from all the input channels. This is the default value
INTERSECTION: intersection of input data. Restricts the overlay to the common areas shared by all the shapes of the input channels.

Details

THMROVR overlays data from input thematic raster layers. Available combination methods include:

Union of input data: overlays all the shapes from all the input channels
Intersection of input data: restricts the overlay to the common areas shared by all the shapes of the input channels

For example, if you overlay a shape on an area of 'No_Data', the UNION option will output the shape while the INTERSECTION option will not because 'No_Data'is not a valid shape and there is no intersection of shapes.

All the attributes from all the input channels are passed to the resulting thematic raster. The function appends an underscore 1, 2, etc. to each channel's attributes, ensuring that each input channel's attributes remains unique in the output. For example:

input channel 1 has attributes user1, user2
input channel 2 has attributes user1, user2
resulting thematic raster attributes would have user1_1, user2_1, user1_2 and user2_2

The output thematic raster gets a new area calculated for the new resultant overlay.

Example

The following example produces a new output thematic raster in "output.pix", based on the two input thematic rasters in irvine.pix.

from pci.thmrovr import thmrovr

fili	=	"irvine.pix"	# input file
filo	=	"output.pix"	# output file will be created
dbic	=	[6,7]	# input thematic raster channels
dbib	=	[]	# no bitmap mask
dboc	=	[]
omethod	=	""	# default, "UNION"

thmrovr( fili, filo, dbic, dbib, dboc, omethod )

Environments	PYTHON :: EASI :: MODELER
Quick links	Description :: Parameters :: Parameter descriptions :: Details :: Example