document axis behavior

diff --git a/rust/doc/src/spv/graphs.md b/rust/doc/src/spv/graphs.md
index 3d653fee8af89175570bac68e48ac85fa95a81c3..0013e94147a77782bf2de0385785381dfeb742d8 100644 (file)
--- a/rust/doc/src/spv/graphs.md
+++ b/rust/doc/src/spv/graphs.md
@@ -470,6 +470,21 @@ axisTransformParameter
 => EMPTY
 ```
 
+`majorTicks` requests drawing the axis itself and tick marks and
+labels.  When the axis is faceted, the axis can either be drawn just
+once or separately in each cell:
+
+- If the dimension has a polar transform, then the axis is drawn in
+  every cell (because there's no reasonable way to draw it just once).
+
+- If `faceting` specifies `method="nest"`, then the axis is drawn in
+  every cell because each cell has a different axis.
+
+- If the `axis` specifies `repeat="always"`, then the axis is drawn in
+  every cell.
+
+- Otherwise, the axis is drawn just once.
+
 `base`, if present, is most commonly zero but can be another number.
 
 `labelAngle`, if present, is -90, 90, 0, 45, 270, or 310 in the corpus.