SMBOYLE

Description

SMBOYLE performs vector smoothing using the Boyle algorithm. The user defines the number of vertices to look ahead before applying the specified tolerance value to determine the new,"smoothed" vertex.

Parameters

Name	Type	Caption	Length	Value range
FILI*	String	Input file name	1 - 192
FILO	String	Output file name	0 - 192
DBVS*	Integer	Input vector segment	1 - 1
TOLVALUE	Float	Tolerance value	0 - 1	0 - Default: 0.5
LOOKAHED	Integer	Vertex look ahead value	0 - 1	1 - Default: 1
DBSN	String	Output segment name	0 - 192	Default: Vectors
DBSD	String	Output segment description	0 - 192
REPORT	String	Report mode	0 - 192	Quick links
MONITOR	String	Monitor mode	0 - 3	ON, OFF Default: ON

* Required parameter

Parameter descriptions

FILI

Specifies the name of the PCIDSK image file containing the input arc layer to be smoothed.

FILO

Specifies the name of the PCIDSK image file to receive the smoothed output vector layer.

If FILO is not specified, FILI is used for the smoothed vector. If FILO is specified but does not exist, a new file is created.

DBVS

Specifies the vector segment containing the input arc layer to be smoothed.

TOLVALUE

Specifies the tolerance value, which is the proportion of distance to place the new vertex between the start vertex and the look ahead vertex.

This value must be greater than zero and smaller than one. The larger the tolerance value, the more pronounced the smoothing effect.

LOOKAHED

Specifies the vertex look ahead value, the number of vertices to "look ahead" each time, before it calculates a new vertex for the resultant smoothed vector.

The look ahead value must be greater than or equal to 1.

DBSN

Specifies a name (up to 8 characters) for the new vector segment.

DBSD

Describes (in up to 64 characters) the contents or origins of the new vector data.

REPORT

Specifies where to direct the generated report.

Available options are:

TERM: generates a report on the terminal (default)
DISK: generates a report on file "IMPRPT.LST"
OFF: turns off report generation
<filename>: appends a report to the specified file

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

The SMBOYLE algorithm produces better results from digitized vectors. For vectors produced by raster-to-vector conversion programs (stepped linework), the "look ahead" value has a large influence; SMMCMASTER is more suited to these vectors. SMBOYLE is not suitable for vectors containing few vertices (the result of raster-to-vector conversion programs can often create these), including small, closed shapes.

SMBOYLE does not alter the start and end vertices of a vector.

Example

Smooth vector layer 25 from "irvine.pix" with TOLVALUE of 0.5 and no sliding average option. The smoothed vector will be stored in a new file named "oirvine.pix".

EASI>FILI     = "irvine.pix"
EASI>FILO     = "oirvine.pix"
EASI>DBVS     = 25
EASI>TOLVALUE =                  ! defaults to 0.5
EASI>LOOKAHED =                  ! defaults to 1
EASI>DBSN     =                  ! defaults to Vectors
EASI>DBSD     =                  ! will be taken from dbvs
EASI>REPORT   =                  ! defaults to TERM
EASI>MONITOR  =                  ! defaults to ON

EASI>run smboyle

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