GRDVEC

Vector encoding


EnvironmentsPYTHON :: EASI :: MODELER
Quick linksDescription :: Parameters :: Parameter descriptions :: Details :: Example :: Related

Back to top

Description


GRDVEC encodes (or burns) vector data into an raster image channel, in an existing file, using the attribute or Z value associated with each line and/or point in a vector segment. GRDINT or PYRINT is used afterwards to grid (interpolate) raster values between encoded vectors yielding a complete surface, for example, a complete Digital Elevation Model (DEM). Note: LINE2RAS is a newer replacement version of GRDVEC.
Back to top

Parameters


Name Type Caption Length Value range
FILV String Input vector file name 0 - 192  
FILE* String Input file name 1 - 192  
DBVS* Integer Input vector segments or layers 1 - 16  
VALU Float Gray-level value list 0 - 16  
DBOC Integer Encoded output channel or layer 0 - 1  
CONNECT Integer Connectedness of lines (4 or 8) 0 - 1 4 | 8
Default: 4
VTYPE String Vector type 0 - 5 LINE | POINT | BOTH
Default: BOTH
FLDNME String Field name to use for elevation values. 0 - 64 SHAPEID | ZCOORD | Field Name
Default: SHAPEID
MONITOR String Monitor mode 0 - 3 ON, OFF
Default: ON

* Required parameter
Back to top

Parameter descriptions

FILV

Specifies the name of the file containing the vector layers to be encoded into the output raster channel. If this parameter is not specified, it is assumed the vector layers are in FILE.

FILE

Specifies the name of the GDB-supported file containing the output raster channel in which to encode the vector data. If FILV is not specified then FILE is assumed to contain the vector layers as well.

DBVS

Specifies up to 16 vector, non duplicate, segments to be encoded. Each segment contains lines and points (for example, elevation contours and markers), where each line or point has an attribute or Z value. All specified vector segments must use the same coordinate system (for example, PIXEL, UTM, etc.).

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.

VALU

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.

DBOC

Specifies one output raster channel to receive the encoded vector line and point data.

Existing data not underneath encoded vector data is NOT changed. The output channel may be of any data type.

If this parameter is not specified, a new 32 bit real output channel is created in FILE and initialized to 0.

CONNECT

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

Supported values are:

VTYPE

Specifies the type of vector data to be encoded. Supported values are:

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.

Values include:
Note: Field names are not case-sensitive. If values are specified in parameter VALU then FLDNME is ignored.

MONITOR

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

Available options are:

Back to top

Details

GRDVEC is used to grid vector data. Gridding is the process of creating a raster image grid, given vector (line and point) data. For example, GRDVEC can encode elevation contour lines into an image channel and then an interpolation program such as GRDVEC or PYRINT completes the griding process by interpolating between lines and points. An alternative interpolation method is to used programs VDEMINGEST and vDEMINT.

GRDVEC encodes the input vector segment data to an output image channel, where attribute values for each vector segment are: specified by the user (in VALU); by actual attribute values stored for each line and point structure in each vector segment (FLDNME specifies the specific field name); the Z value for each vertex (FLDNME="ZCOORD"); or the shape id (FLDNME="SHAPID"). If the Z value for each vertex is requested then the Z values along a line segment are interpolated between vertices. The user must specify either 4-connectedness or 8-connectedness for line segments encoded on the image. The user has the option of encoding only line structures, only point structures, or both types of structures.

If the vector coordinates are not stored in PIXEL coordinates, the input file must be georeferenced (using GEOSET) prior to running GRDVEC. The georeferencing units must be the same those used in collecting the vector data. The current georeferencing information for the input file may be obtained by running GEOREP.

Use the CLR program to clear all pixels in the output channel to a background value (usually zero) before encoding vector data with GRDVEC. If more than 16 vector segments must be encoded, GRDVEC can be run again, using the same output channel.

Back to top

Example

Run GRDVEC to encode VED transportation lines in vector segment 25 of irvine.pix into the output image (channel 13). The lines are encoded with their VED designation held in the field named "ATTRIBUTE". 4-connectedness is used. Line data are encoded, point data are ignored. Before encoding the output channel is initialized with the value 0.

EASI>FILE = "irvine.pix"	            
EASI>DBOC = 13
EASI>VALU = 0
EASI>DBOW =

EASI>RUN CLR  
            
EASI>FILV = ""            
EASI>FILE = "irvine.pix"		
EASI>DBVS = 25
EASI>VALU = 
EASI>DBOC = 13
EASI>CONNECT = 4
EASI>VTYPE = "LINE"
EASI>FLDNME = "ATTRIBUTE"		

EASI>RUN GRDVEC

© PCI Geomatics Enterprises, Inc.®, 2024. All rights reserved.