[GRASS-dev] [GRASS GIS] #1443: GRASS 7: d.vect grid drawing problem

[GRASS GIS]

#1443: GRASS 7: d.vect grid drawing problem
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  Reporter:  neteler  |      Owner:  grass-dev@…
      Type:  defect   |     Status:  new
  Priority:  normal   |  Milestone:  7.0.5
 Component:  wxGUI    |    Version:  svn-trunk
Resolution:           |   Keywords:  d.vect
       CPU:  x86-64   |   Platform:  Linux
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Comment (by mmetz):

 Replying to [ticket:1443 neteler]:
 > When importing attached SHAPE file of a 10 degree lines grid, the
 horizontal lines are not draw.

 This is because for Lat/Lon, the display drivers draw the shortest line
 between two vertices (longitude wrapping). A line with two vertices -180,0
 and 180,0 has length zero because start and end coordinates are identical,
 the line is not displayed. Another line with two vertices -10,0 and 10,0
 is drawn from -10,0 going east to 10,0 (the shortest line) and not from
 -10,0 going west over -180, then to 10,0. Special treatment for zero-
 length lines is not an option because they can appear after vector
 cleaning.

 For the attached shapefile, the horizontal lines need to be broken at
 their intersections with vertical lines (v.clean tool=break), then the
 horizontal lines become visible in the display.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/1443#comment:3>
GRASS GIS <https://grass.osgeo.org>