What you want to do is a cartographic generalization operation called displace. You might have a look at GRASS v.generalize, it has an option for displacement.

What I propose, however, is using geometry generator with the function offset_curve( ) and for the distance use the variable @map_scale, divided by a constant.

The line in the middle should not be offset at all and the lines at the right and left should be offset in the respective direction. For this, create a new attribute offset and add for each line a value of 0 (no offset), 1 (offset to the left) or -1 (offset to the right). You could also set other numbers to get different offset distances for different roads: the higher the number, the higher the offset.

Combine these elements with geometry generator and this expression (change 500 to a value that fits your data):

offset_curve ($geometry, "offset" * @map_scale/500)

When you now zoom out, the lines to the right and left move away from the line in the center:

Screenshot 1: black solid line: mid-line (no offset), black dotted line: original line that must be offset, red-lines: offsetted lines:

Screenshot 2: result when zooming out:

What you want to do is a cartographic generalization operation called displace. You might have a look at GRASS v.generalize, it has an option for displacement.

Principal idea of the solution

What I propose, however, is using geometry generator with the function offset_curve( ) and for the distance use the variable @map_scale, divided by a constant.

How to implement it

1. The line in the middle should not be offset at all and the lines at the right and left should be offset in the respective direction. For this, create a new attribute offset and add for each line a value of 0 (no offset), 1 (offset to the left) or -1 (offset to the right). You could also set other numbers to get different offset distances for different roads: the higher the number, the higher the offset.

2. Combine these elements with geometry generator and this expression (change 500 to a value that fits your data):

   offset_curve ($geometry, "offset" * @map_scale/500)
   

When you now zoom out, the lines to the right and left move away from the line in the center:

Screenshot 1: black solid line: mid-line (no offset), black dotted line: original line that must be offset, red-lines: offsetted lines:

Screenshot 2: result when zooming out:

What you want to do is a cartographic generalization operation called displace. You might have a look at GRASS v.generalize, it has an option for displacement.

What I propose, however, is using geometry generator with the function offset_curve( ) and for the distance use the variable @map_scale, divided by a constant.

The line in the middle should not be offset at all and the lines at the right and left should be offset in the respective direction. For this, create a new attribute offset and add for each line a value of 0 (no offset), 1 (offset to the left) or -1 (offset to the right). You could also set other numbers to get different offset distances for different roads: the higher the number, the higher the offset.

Combine these elements with geometry generator and this expression (change 500 to a value that fits your data):

offset_curve($geometry, "offset" *@map_scale/500)

When you now zoom out, the lines to the right and left move away from the line in the center:

Screenshot 1: black solid line: mid-line (no offset), black dotted line: original line that must be offset, red-lines: offsetted lines:

Screenshot 2: result when zooming out:

What you want to do is a cartographic generalization operation called displace. You might have a look at GRASS v.generalize, it has an option for displacement.

What I propose, however, is using geometry generator with the function offset_curve( ) and for the distance use the variable @map_scale, divided by a constant.

The line in the middle should not be offset at all and the lines at the right and left should be offset in the respective direction. For this, create a new attribute offset and add for each line a value of 0 (no offset), 1 (offset to the left) or -1 (offset to the right). You could also set other numbers to get different offset distances for different roads: the higher the number, the higher the offset.

Combine these elements with geometry generator and this expression (change 500 to a value that fits your data):

offset_curve ($geometry, "offset" * @map_scale/500)

When you now zoom out, the lines to the right and left move away from the line in the center:

Screenshot 1: black solid line: mid-line (no offset), black dotted line: original line that must be offset, red-lines: offsetted lines:

Screenshot 2: result when zooming out: