VWRITE

Description

Writes vector (line and point) data from an existing PCIDSK database vector layer to a new text file.

Note: Use FEXPORT to write text files used by third-party GIS software.

Parameters

Name	Type	Caption	Length	Value range
FILE *	String	Input file name	1 - 192
DBVS *	Integer		1 - 1
FILV *	String	Output vector file name	1 - 192
DMSFORM	String	Deg/Min/Sec Format: ON/OFF	0 - 3	ON \| OFF Default: OFF
FLDNME	String	Field name for attribute value to be written	0 - 64	Default: Attribute

* Required parameter

Parameter descriptions

FILE

Specifies the name of the PCIDSK file that contains the vector segment (type VEC:116) to be written to the text file.

DBVS

Specifies the input vector segment (type VEC:116) to be written to the text file.

FILV

Specifies the name of the text file to be created to receive the written vector information.

This is NOT a PCIDSK file. The specified output file must not exist before running VWRITE.

DMSFORM

Specifies whether LONG/LAT coordinates should be output using real numbers or degrees/minutes/seconds/hemisphere strings.

Available options are:

OFF: degrees are output as signed real numbers (-DDD.DDDDDD decimal format); this is the default value
ON: d, ' and " symbols are used as separators between degrees, minutes, seconds, and hemisphere (DDdMM'SS.SS"H string format)

This parameter is ignored if vector units are not LONG/LAT.

FLDNME

Specifies the field name that contains an attribute value to be written for each shape.

If this parameter is specified as ZCOORD, the actual z-coordinates of the vectors are used. Field names are not case-sensitive, and they do not need to be specified in complete form. If more than one match exists, the first name is used.

Supported values are:

ATTRIBUTE: uses the field named "ATTRIBUTE" in the vector segment
ZCOORD: uses the actual z-coordinates of the input vectors
SHAPEID: uses the ShapeID of the input vectors
<field>: uses the specified field

Details

VWRITE writes vector (line and/or point) information from a vector segment (type VEC:116) to a text file. The use of an intermediate file to hold vector information allows vector data from a PCIDSK file to be edited.

When running VWRITE, the vector information held in the vector segment (DBVS) of the PCIDSK file (FILE) is written to the specified text file (FILV) in the output format specified below.

 Structure Type     Attribute Value 
 X-Coordinate      Y-Coordinate
 X-Coordinate      Y-Coordinate
 ...

where:

Structure Type is the character string LINE or POINT
Attribute Value is an integer value
X-coordinates and Y-coordinates are real values

Fields are separated by a comma or space.

If vector units are LONG/LAT, DMSFORM specifies the format for the longitude and latitude coordinates.

Each vector may contain more than one attribute field. The FLDNME parameter is used to specify which attribute field to use.

Examples

Write the vectors stored in segment 25 (DLGTRANS) on irvine.pix to a text file. DMSFORM is ignored because vectors are stored using UTM units.

EASI>file	=	"/demo/irvine.pix"
EASI>dbvs	=	25
EASI>filv	=	"dlgtrans.txt"
EASI>dmsform	=		! default, "OFF"
EASI>fldnme	=		! default, "Attribute"

EASI>RUN VWRITE

The beginning of the text file dlgtrans.txt looks like this:

     LINE        1700210
 440855.00    3732105.00
 440849.34    3732100.09
 440742.86    3732131.28
 440471.17    3732145.78
 440283.44    3732180.05
 440143.81    3732191.14
 440052.54    3732217.15
 440024.75    3732240.19
 439992.00    3732281.05
     LINE        1700210
 439815.21    3732051.08
 439827.98    3732061.15
 439911.93    3732080.92
 439975.36    3732070.34
 440021.10    3732072.57
     LINE        1700205
 439815.21    3732051.08
 439805.13    3732063.85
 439783.19    3732201.16
 439773.04    3732203.76

Suppose that the PCIDSK file geometry.pix has the following vector data in segment 3 and that its units are PIXEL. The lines have an attribute value of zero and the point (2,2) has an attribute value of 999.

              (1,1)   (8,1)    (18,1)
                +-------+         +
                | x(2,2)|        /
                |       |       /
                +-------+      +
              (1,4)  (8,4)  (15,4)

Write this information to a text file as follows:

EASI>file	=	"geometry.pix"
EASI>dbvs	=	3
EASI>filv	=	"vectors.dat"
EASI>dmsform	=		! default, "OFF"
EASI>fldnme	=		! default, "Attribute"

EASI>RUN VWRITE

The output text file vectors.dat contains the following:

    LINE              0
    1.000         1.000
    8.000         1.000
    8.000         4.000
    1.000         4.000
    POINT           999
    2.000         2.000
    LINE              0
   18.000         1.000
   15.000         4.000

Environments	PYTHON :: EASI :: MODELER
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