Grid

Toolbar:
It is possible to use an auxiliary grid of lines to define 2D points easily. The 'snap' function can be activated to force points to grid intersections.
From the preferences window (see Preferences) it is possible to set the separation between lines and to show the origin, extents, etc. of the coordinates.

There is a small button in the bottom right-hand corner that activates or deactivates the grid and 'snap' functions.