Difference between revisions of "Convert points to lines"

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(+Triangulation)
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'''Q:''' Is there a way to construct a vector line(s) map connecting selected points?
 
'''Q:''' Is there a way to construct a vector line(s) map connecting selected points?
  
'''A:''' There are two possibilities:
+
'''A:''' There are several possibilities:
  
 
=== Converting points map into lines map ===
 
=== Converting points map into lines map ===
  
You can use {{cmd|v.in.lines|version=65}} for that. The input can be generated with {{cmd|v.out.ascii}}.
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You can use {{cmd|v.in.lines}} for that. The input can be generated with {{cmd|v.out.ascii}}.
  
 
Spearfish example:
 
Spearfish example:
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   v.category in=mylines out=lines_with_cat option=add
 
   v.category in=mylines out=lines_with_cat option=add
 
</source>
 
</source>
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 +
=== Triangulate the points into a lines map ===
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 +
Use {{cmd|v.delaunay}} for that.
  
 
== See also ==
 
== See also ==
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* [[Convert vector types]]
 
* [[Convert vector types]]
 
* [[Convert lines to areas]]
 
* [[Convert lines to areas]]
 +
* [[Convert areas to lines]]
  
 
[[Category: FAQ]]
 
[[Category: FAQ]]
 
[[Category: Vector]]
 
[[Category: Vector]]

Revision as of 16:50, 14 August 2014

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

Triangulate the points into a lines map

Use v.delaunay for that.

See also