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I have a shapefile consisting of two links which are crossing over each other.

I want to create an empty space at the point of intersection of the two links.

As of now, I have been manually doing this like this:

  1. Split the line at two points near the intersection. And then remove that feature.
  2. Similarly carry out this for the other line.

So by doing this, I create a empty space at the point of intersection.

I want to know whether there is any better way to achieve this using a plugin or any other way?

Can a plugin can be created specifically for this task ? (I'm ready to write one, if this is achievable.)

Below is an image where one link touches other link. Now, I want to create an empty space there. enter image description here

This is the output I'm expecting:

enter image description here

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2  
Why do you need to do that btw? Do you have a sample dataset we can work with? An illustration would most useful, too. –  R.K. Jan 17 '13 at 14:04
    
@R.K. I have updated with snapshots. –  Sibi Jan 17 '13 at 14:12
    
Is the purpose cartographic or analytic? If it's cartographic, it would be a bad idea to actually change the underlying data in order to achieve a particular mode of rendering them: knowing that would suggest purely cartographic solutions. If it's analytic, would you mind telling us what kind of analysis these changes are intended to support? (In effect it looks like you are asking to destroy information about connectivity, which is an unusual and curious thing to do.) –  whuber Jan 17 '13 at 20:12
    
@whuber It is for analytic purpose. Once the empty space is defined, I will feed the shapefile to a simulator which will be configured to identify them as intersection. –  Sibi Jan 17 '13 at 21:17

2 Answers 2

up vote 8 down vote accepted

I would create intersection points, then buffer them by the distance of 'space' you want. Intersect the buffer with the lines, and delete those that intersect. Done.

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Another way to go at it would be:

Identify street intersections using the Line Intersections tool in the Sextante Toolbox

enter image description here

or the Vector Menu.

enter image description here

Just intersect your line shapefile with itself. This would result in a new point layer of the intersection points.

You can then buffer the intersection points to your desired size as in Darren's answer.

After that, use the Difference tool to create the 'spaces'. The end result should be what you need.

enter image description here

I hope that helps. Good luck.

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