RAS2THMR

Description

RAS2THMR creates a thematic raster layer by creating a linked attribute table for the input raster data. The attribute table includes information about the input raster, such as the unique pixel value, the area covered by each unique pixel value and, when classification metadata is present, class names and descriptions.

Parameters

Name	Type	Caption	Length	Value range
FILI *	String	Input file name	1 - 192
DBIC *	Integer	Input raster channel	1 - 1
FILO *	String	Output file name	1 - 192
DBOC	Integer	Output raster channel	0 - 1
DBSD	String	Output segment descriptor	0 - 64	Default: Attributes from Raster
AREAONLY	String	Only create area attribute	0 - 3	YES| NO Default: YES
NODATVAL	Float	NoData value	0 - 1
FOPTIONS	String	Output file options	0 - 64
MONITOR	String	Monitor mode	0 - 3	ON, OFF Default: ON

* Required parameter

Parameter descriptions

FILI

Specifies the file that contains the input raster channel to be processed.

DBIC

Specifies the input raster channel to be processed.

Ranges of channels or segments can be specified with negative values. For example, {1,-4,10} is internally expanded to {1,2,3,4,10}. When you are not specifying a range in this way, only 48 numbers can be specified explicitly.

FILO

Specifies the name of the PCIDSK database file that will contain the output raster and attribute table.

The attribute results are stored as a vector layer, which is linked to the input raster channel through the newly created PixelValue attribute.

If the specified name does not exist, a new file is created with one channel and one vector layer containing the output result.

DBOC

Specifies the output raster channel that will be written to.

If the output file exists, a value for DBOC must be specified. Defaults to 1 only when a new file is created.

Ranges of channels or segments can be specified with negative values. For example, {1,-4,10} is internally expanded to {1,2,3,4,10}. When you are not specifying a range in this way, only 48 numbers can be specified explicitly.

DBSD

Specifies a descriptor for the output vector segment holding the attributes. The descriptor can be up to 64 characters.

If not specified, the default descriptor is "Attributes from Raster".

AREAONLY

Specifies which attributes to add to the output data.

You can create an attribute table consisting of only the area or the area and perimeter:

• YES: Specifies that only attributes for the defined area are added to the output layer. This is the default value.
• NO: Attributes for the defined area and its perimeter are added to the output layer.

NODATVAL

Specifies a NoData (or background) value for the input channel. Pixels with this value are excluded from processing.

If no value is specified for this parameter, the NoData value for the channel is taken from the input layer metadata.

FOPTIONS

The file-creation options to be applied when creating the output PCIDSK file. These are specific to the file format; the default of no options is allowed. FOPTIONS can be used to specify the compression schemes, file format subtypes, and other information.

The options are described in GDB file formats in the Technical Reference section of the CATALYST Professional online Help.

This parameter is optional.

MONITOR

The program progress can be monitored by printing the percentage of processing completed. A system parameter, MONITOR, controls this activity.

Available options are:

• ON: Turns the monitor ON (default)
• OFF: Turns the monitor OFF (recommended if running in batch or background mode)

Details

RAS2THMR creates a thematic raster layer from an input raster layer with an associated attribute table. The attribute table is stored as a vector layer, which is linked to the raster output channel through metadata.

The attribute values can include Area only or Area and Perimeter. These values are calculated based on the pixels of the input raster channel.

If the input raster contains suitable classification metadata, that information is automatically transferred to the appropriate fields in the output attribute table. That is, when the input raster is the result of a PCI classification process, two addtional fields, Name and Description, are created in the output thematic raster.

The segment name and descriptor are created automatically from the input raster file.

Example

Update channel 6 in irvine.pix to have an associated attribute table and therefore be a thematic raster. A new vector segment will be appended to irvine.pix to store the raster attributes.

EASI>FILI     = "irvine.pix"    ! input raster file
EASI>DBIC     = 6               ! using channel 6 from irvine.pix
EASI>FILO     = "irvine.pix"    ! output file to be created
EASI>DBOC     = 6               ! update the input channel
EASI>DBSD     =                 ! defaults to "Attributes from Raster"
EASI>AREAONLY =                 ! defaults to "YES" so only Area is computed
EASI>NODATVAL =                 ! defaults to DBIC's NO_DATA_VALUE
EASI>FOPTIONS =                 ! unnecessary since FILO exists

EASI>run ras2thmr