.TH v.reclass 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBv.reclass\fR\fR  \- Changes vector category values for an existing vector map according to results of SQL queries or a value in attribute table column.
.SH KEYWORDS
vector, reclassification, attributes
.SH SYNOPSIS
\fBv.reclass\fR
.br
\fBv.reclass \-\-help\fR
.br
\fBv.reclass\fR \fBinput\fR=\fIname\fR  [\fBlayer\fR=\fIstring\fR]   [\fBtype\fR=\fIstring\fR[,\fIstring\fR,...]]  \fBoutput\fR=\fIname\fR  [\fBcolumn\fR=\fIname\fR]   [\fBrules\fR=\fIname\fR]   [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-\-overwrite\fR" 4m
.br
Allow output files to overwrite existing files
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBinput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of input vector map
.br
Or data source for direct OGR access
.IP "\fBlayer\fR=\fIstring\fR" 4m
.br
Layer number or name
.br
Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
.br
Default: \fI1\fR
.IP "\fBtype\fR=\fIstring[,\fIstring\fR,...]\fR" 4m
.br
Input feature type
.br
Options: \fIpoint, line, boundary, centroid\fR
.br
Default: \fIpoint,line,boundary,centroid\fR
.IP "\fBoutput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name for output vector map
.IP "\fBcolumn\fR=\fIname\fR" 4m
.br
The name of the column whose values are to be used as new categories
.br
The source for the new key column must be type integer or string
.IP "\fBrules\fR=\fIname\fR" 4m
.br
Full path to the reclass rule file
.SH DESCRIPTION
\fIv.reclass\fR allows user to create a new vector map based on
the reclassification of an existing vector map. It also allows the user
to change the \fIkey column\fR away from the default of \(dq\fBcat\fR\(dq with
the \fBcolumn\fR option.
.PP
Rules file may contain on each row either pair:
.br
.nf
\fC
keyword value
\fR
.fi
(separated by space) or comment beginning with \(cq#\(cq (hash).
Definition of new category begins with keyword \fIcat\fR followed
by the new category value.
Keyword \fIwhere\fR specifies SQL where condition.
.SH NOTES
No table is created for the reclassed map if the \fBcolumn\fR option is
used and the column type is integer (as the result could contain ambiguities).
If the \fBcolumn\fR option is used and the column type is string, a new
table is created containing the newly generated cat numbers and a single
column containing the unique string column values, sorted in alphabetical
order.
.PP
For dissolving common boundaries, see
\fIv.dissolve\fR.
.SH EXAMPLES
.SS Example 1: Reclass by rules
.br
.nf
\fC
v.reclass input=land output=land_u type=boundary rules=land.rcl
\fR
.fi
the rules file contains :
.br
.nf
\fC
# land reclass file
cat 1
where use = \(cqE13\(cq and owner = \(cqJara Cimrman\(cq
cat 2
where use = \(cqE14\(cq
\fR
.fi
Produces a new vector area map \fIland_u\fR containing boundaries from
\fIland\fR with area category values selected from database by SQL
select statement:
.br
select id from tland where use = \(cqE13\(cq and owner = \(cqJara Cimrman\(cq
changed to category 1;
.br
values selected from database by SQL select statement:
.br
select id from tland where use = \(cqE14\(cq changed to category 2.
.SS Example 2: Reclass by attribute column
(North Carolina sample dataset)
.br
.br
.nf
\fC
v.reclass in=streams out=streams_by_type column=I_vs_P
v.db.select streams_by_type
cat|I_vs_P
1|intermittent
2|perennial
\fR
.fi
.SH KNOWN ISSUES
No table is created for reclassed layer if \fBrules\fR option is used.
.SH SEE ALSO
\fI
v.dissolve,
v.extract
\fR
.PP
\fIGRASS SQL interface\fR
.SH AUTHOR
R.L. Glenn, USDA, SCS, NHQ\-CGIS
.br
from v.reclass to v.db.reclass and later to v.reclass in 5.7 rewritten
by Radim Blazek
.SH SOURCE CODE
.PP
Available at: v.reclass source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual