In QGIS, is there a way to constrain a 'move by vertex' along the x or y axis?

In the picture below, I would like to constrain the edit movement along the y-axis as shown in the bold red dashed line. (THIS IS WHAT I WANT.)

The default 'floaty' behavior is shown by the thin red line & NOT what I want in this case.

QGIS move by vertex constrained to y-axis


Yes, you can enable the Advanced digitizing tools whilst editing. When enabled, there is an active function which snaps the selected vertices to the nearest common angle. You can open the advanced tools from the menubar:

View > Panels > Advanced Digitizing Panel

Click the left-most icon to ensure it is enabed and set the common snapping angle:

Advanced digitizing panel

Then use the Node tool (or Vertex tool if using QGIS 3.0), select the vertices and move the cursor vertically whilst staying close to the 90 degree angle:


You can do the same horizontally:


Note: the layer must be in a projected CRS in order to use the Advanced Digitizing Tool.

Tested on QGIS 3.0 for Win7 64-bit.

  • @cm1 - Most welcome! Glad it helped :) – Joseph Mar 12 '18 at 14:56

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