I am trying to draw parallel lines at a set spacing (say 50 ft apart) for multiple layers at a time. Is there a quick way to draw multiple lines in one go? example of what I would like to create below. Had to try and do it manually, which I would like to avoid.

enter image description here

  • is this for visual effect only or would you like to have spatial data to do analysis or other things on? – SaultDon Feb 14 at 20:41
  • Spatial data preferably. Although both could be potentially helpful – efrank Feb 14 at 23:10

If you have already a layer with lines, you could try a tool from the processing tool box. (I've got a german QGIS, so I don't really now the english name for it, sorry. Search for 'parallel'.) In the screenshot the tool generated the red lines in a temporary layer. Paramter for the new line(s) was '1' in distance 10 Meters. In the result you have the orignal line plus one extra on the northern (left) side of it. If you choose a negative value, the line(s) are created at the opposite side.

enter image description here

If you have the data already in postgis or spatialite or would like to have something dynamic, you can work with ST_OffsetCurve. E.g. if you want a separate line on the lefthand and seperate one on the righthand, I would create two extra geometry columns in the database to store them. Then update all with a statement. For a dynamic solution -means create the parallel lines at once when a new line is created- you could add triggers which do this automatically.

  • it's called Array of offset (parallel) Lines – SaultDon Feb 14 at 23:15
  • Also supports batch proccesing, to create both sides for all the layers in one go. – Gabriel De Luca Feb 15 at 0:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.