LINE2RAS

Description

LINE2RAS encodes (burns) vector data into a raster image channel using the attribute or Z value associated with each line and/or point in a vector segment. PYRINT is used afterwards to grid (interpolate) raster values between encoded vectors yielding a complete surface, for example, a complete Digital Elevation Model (DEM).

Parameters

Name	Type	Caption	Length	Value range
FILI *	String	Input file name	1 - 192
DBVS *	Integer	Input vector segment	1 - 1
FILO	String	Output file name	0 - 192
DBOC	Integer	Encoded raster channel	0 - 1
FLDNME	String	Field name to use for elevation values.	0 - 64	SHAPEID | ZCOORD | Field Name
BURNVAL	Float	Value to burn	0 - 1	Default:
CONNECT	Integer	Connectedness of lines (4 or 8)	0 - 1	4 | 8 Default: 8
PIXRES	Float	Output pixel resolution (m)	0 - 2
FTYPE	String	Output file type	0 - 4	Default: PIX
FOPTIONS	String	Output file options	0 - 64
MONITOR	String	Monitor mode	0 - 3	ON, OFF Default: ON

* Required parameter

Parameter descriptions

FILI

Specifies the name of the file containing the vector layers to be encoded into the raster channel.

DBVS

Specifies the vector segment from the input file to be encoded. The input vector segment contains lines (such as elevation contours), where each line has an attribute value. All specified vector segments must use the same coordinate system (PIXEL, UTM, etc.).

FILO

Specifies the name of the file to receive the output raster channel. If this parameter is not specified, FILI is used.

If the output file is specified but does not already exist, a new file is created with a single 32 bit real channel to encode the vector data.

DBOC

Specifies the output raster channel to receive the encoded vector data.

If the specified output file FILE exists, this parameter must be specified and the channel must exist. If the output file does not exist, this parameter should be left unspecified.

FLDNME

Specifies the field containing the elevation (or Z) values. The field name must exist in the attribute table of the vector layer. The acceptable range of elevation values depends on the data type of the output channel.

BURNVAL

Optionally specifies a value to use during encoding for ALL lines and points in the input vector segment. Use of this parameter will mean that the FLDNME parameter is ignored.

The range for this value depends on the data type of the output channel.

CONNECT

Specifies the connectedness for line segments encoded into the output image channel. Points are always encoded as a single dot.

PIXRES

Specifies the output pixel resolution, in meters, for the new output file (FILO) if it is created.

The specified pixel size determines the number of pixels and lines in the output file. A smaller pixel size results in a larger output file and increased computation time.

PIXRES values are used only when the output file (FILO) is specified but does not yet exist; otherwise PIXRES is ignored. If this parameter is defaulted, the pixel resolution is taken from the georeferencing of input file FILI.

FTYPE

Optionally specifies the output file format type, represented by a three- or four-letter code.

For a complete list of GDB-recognized file types and their codes, see GDB file formats in the Technical Reference section of the CATALYST Professional online Help.

FOPTIONS

Different options are available for different file types (see the FTYPE parameter). The options are described in GDB file formats in the Technical Reference section of the CATALYST Professional online Help.

For PIX format, FOPTIONS defaults to BAND.

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

LINE2RAS encodes the vector segment data from the input file to an output image channel. Attribute values for each vector segment are either specified by the user (parameter BURNVAL), or by actual attribute values stored for each line and point structure in the vector segment (a field or the Z coordinate using parameter FLDNME).

LINE2RAS is used in gridding vector data. Gridding is the process of creating a raster image grid, given vector (line and point) data. For example, LINE2RAS can encode elevation contour lines into an image channel after which an interpolation function such as PYRINT can be used.

If the units for storing vector data are not PIXEL, but are UTM or any other type, the database must be georeferenced (using GEOSET) prior to running LINE2RAS. The units for georeferencing must be the same as those used to collect the vector data. The current georeferencing information for the database may be obtained by running GEOREP.

If the output file FILO already exists the CLR function can be used to clear all pixels in the output channel to a background value (usually zero) before encoding vector data with LINE2RAS. If the output file is created then a background value and data type for the channel are automatically determined. Typically the background value is 0 unless this conflicts with the burned in vector data values.

Only one vector layer (or segment) may be encoded at a time. LINE2RAS can be run multiple times, using the same output channel, if more than one vector layer needs to be encoded. Vector data must all be in the same projection as the output file. Function VECPRO can be used to reproject vector layers.

Each vector may contain more than one attribute field. The FLDNME (Field Name) parameter specifies the attribute field to use or whether the actual Z values associated with each vertex or point should be used.

Function GRDVEC performs a similar function to LINE2RAS but can only write into an existing file while LINE2RAS can automatically create an output file or write to an existing file.

Example

Create a raster channel from vector channel 25 in the file "irvine.pix". This exercise reads vector data from the input file "irvine.pix" and stores it to a raster image channel in the newly created output TIF format file, "riv25.tif" in the same projection as "irvine.pix" and at 10m resolution.

EASI>FILI     = "irvine.pix"    ! input file
EASI>DBVS     = 25              ! input line layer
EASI>FILO     = "irv25.tif"     ! output file
EASI>DBOC     =                 ! output channel
EASI>FLDNME   =                 ! no field name specified
EASI>BURNVAL  = 100             ! pixel value for all shapes
EASI>CONNECT  = 8               ! eight connected lines
EASI>PIXRES   = 10,10           ! output resolution
EASI>FTYPE    = "TIF"           ! output format type
EASI>FOPTIONS =                 ! format options
 
EASI>run line2ras