Aligning grid lines to axis ticks in lattice graphics <p>Is there a way to align grid lines if they are chosen custom? By default, panel.grid(h=-1,v=-1) does the job, but I'd like to refine the grid according to the axis ticks. Setting h and v to negative lengths of axis ticks doesn't always work.</p> <p>Update: Below is an example. I would like to achieve that horizontal grid lines match the y-axis ticks. Currently half of horizontal grid lines are missing.</p> <pre><code>library(lattice) G &lt;- cut(trees$Girth, seq(8, 22, by = 3)) p &lt;- xyplot(Height ~ Volume | G, data = trees, scales = list(x = list(alternating = 3, at = seq(10, 60, by = 5)), y = list(alternating = 3, at = seq(65, 85, by = 2.5))), panel = function(x, y, ...){ panel.grid(v = -11, h = -9) panel.xyplot(x, y, ...)}) print(p) </code></pre> <p>What I currently get is this:</p> <p><img src="https://i.stack.imgur.com/QzeSN.png" alt="enter image description here"></p>