[OpenLayers-Trac] [OpenLayers] #1533: Cannot modify a feature (linestring) that have two points at the same position

[OpenLayers]

#1533: Cannot modify a feature (linestring) that have two points at the same
position
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  Reporter:  pvalsecc               |       Owner:  tschaub
      Type:  bug                    |      Status:  new    
  Priority:  minor                  |   Milestone:         
 Component:  Control.ModifyFeature  |     Version:  2.6    
Resolution:                         |    Keywords:         
     State:  Needs Discussion       |  
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Comment (by pvalsecc):

 Replying to [comment:4 elemoine]:
 > My question was unclear. Sorry. Let me try again: I'm actually wondering
 why favoring real vertices over virtual ones would actually be better.
 Wouldn't there be cases where user would want virtual vertices to be
 favored? I really don't know, just asking...

 Here is an analogy: do you favor virtual money or real money? Beware, I
 know your boss ;-)

 Since the vertex is double anyway, there is no need to add another one
 (what will be done if we favor the virtual points). Therefore, I think
 it's more "logical" to favor the real vertices.

 Just try to play with the middle point of the linestring in this example
 (ModifyFeature not patched):
 http://www.thus.ch/~patrick/openlayers/examples/modify-feature.html

 It's not cool to have yet another point created during your first try. And
 chances are great that the next try you'll do, the wrong point will be
 moved. Then, you'll have to delete the new vertex that has been created
 during the first try. Imagine a "normal" user playing with this geometry.

 Now, if the user really wants to add a point, he can just move one of the
 points, create the vertex and move back the point. But since he (most
 likely) won't know there are two vertices at the same position, how can he
 want that?

 My last argument, would be about the opacity of the vertices. Since the
 real vertices are more opaque than the virtual ones, I think it's fair
 they have more priority.

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Ticket URL: <http://trac.openlayers.org/ticket/1533#comment:5>
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