Convert points to lines

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Q: Is there a way to construct a vector line(s) map connecting selected points?

A: There are several possibilities:

Converting points map into lines map

You can use v.in.lines for that. The input can be generated with v.out.ascii.

Spearfish example:

  v.out.ascii archsites fs=, where="cat=1 or cat= 3"
  593493,4914730,1
  589860,4922000,3
 
  # so:
  v.out.ascii archsites fs=, where="cat=1 or cat= 3" | cut -d',' -f1,2 | \
      v.in.lines in=- out=myline fs=,
  v.category in=myline out=line_with_cat option=add

Converting CSV points file into lines map

Suppose you have a CSV file "mypoints.csv" containing three point-pairs to be connected (start point coordinates, end point coordinates):

 east1,north1,east2,north2
 593493,4914730,589860,4922000
 590400,4922820,593549,4925500
 600375,4925235,606635,4920773

We can convert these three point pairs into three lines:

  cat mypoints.csv | grep -v "north1" | awk -F',' '{printf "%f,%f\n%f,%f\nNaN,NaN\n",$1, $2 ,$3 ,$4}' > mypoints_formatted.csv
  v.in.lines in=mypoints_formatted.csv out=mylines fs=,
  v.category in=mylines out=lines_with_cat option=add

Script to convert CSV points file into ASCII file for v.in.lines import

#!/bin/bash                                    
# letzte Änderung 09.01.2015 
# gpx Leitungsdaten für v.in.lines konvertieren         

FILE=test.csv

head -1 $FILE > te3.tmp
N=`cut -c 11-20 te3.tmp`
E=`cut -c 22-31 te3.tmp`
rm *.tmp

awk -v E=$E -v N=$N '  
BEGIN {
FS=";"
z=0
}
		{if(z != 1){
		z=z+1
		printf("%10.7f\%s\%10.7f\%s\n" \
		,E,"|",N,"|")
		}						
		else{
		E=$5
		N=$4
		printf("%10.7f\%s\%10.7f\%s\nNaN|NaN|\n" \
		,$5,"|",$4,"|")
		z=0
		}
	}
END{ 	
}' $FILE > formatted_csv.txt

## Now run import:
# v.in.lines in=formatted_csv.txt  out=test

Triangulate the points into a lines map

Use v.delaunay for that.

See also