diff --git a/server/src/atlas/heightmap.rs b/server/src/atlas/heightmap.rs
index f45724997..daa76095f 100644
--- a/server/src/atlas/heightmap.rs
+++ b/server/src/atlas/heightmap.rs
@@ -4,11 +4,12 @@
 //! **16-bit grayscale `heightmap.png`** stored next to the color `reliefmap.png`
 //! in the body's wiki directory (path from `bodies.terrain_reference`). The
 //! grayscale luminance is the normalized elevation; this is the single source
-//! of truth — no `systems.db` BLOB. The file is high-resolution (canonically
-//! 2048×1024) so the lower cascade layers (region/block/tile) have real local
-//! detail; **Layer 1** (continental drainage/basins/mountain-ranges) calls
-//! [`BodyHeightmap::downsample`] to `GRID_W × GRID_H` first, decoupling the
-//! continental compute cost from the stored resolution.
+//! of truth — no `systems.db` BLOB. The file is canonically 1024×512 (D-202
+//! amended): native elevation detail for the lower cascade layers
+//! (region/block/tile), while **Layer 1** (continental drainage/basins/
+//! mountain-ranges) calls [`BodyHeightmap::downsample`] to the
+//! `GRID_W × GRID_H = 512×256` working grid first, decoupling continental
+//! compute cost from the stored resolution.
 //!
 //! Elevation values are normalized to [0.0, 1.0]. `sea_level` is body metadata
 //! (carried alongside, not in the PNG) below which terrain is ocean.