diff --git a/vendor/clouds3d.js b/vendor/clouds3d.js
index d524183..ec6ae60 100644
--- a/vendor/clouds3d.js
+++ b/vendor/clouds3d.js
@@ -339,7 +339,13 @@ function drawTileAt(lng, perp, dx, dz, centerTileX, centerTileY) {
         return Promise.resolve(false);
     }
     return fetchTileImage(tileX, tileY).then(function(img) {
-        groundCtx.drawImage(img, canvasX, canvasY);
+        // Rotate image 180 degrees: draw with negative width and
+        // negative height, anchored at the tile's bottom-right corner
+        // (canvasX + 256, canvasY + 256). After this, image north
+        // (high lat) is at canvas bottom and image south at canvas
+        // top; image east at canvas right, image west at canvas left.
+        groundCtx.drawImage(img, canvasX + GROUND_TILE_SIZE, canvasY + GROUND_TILE_SIZE,
+            -GROUND_TILE_SIZE, -GROUND_TILE_SIZE);
         groundLoadedTiles[tileX + '_' + tileY] = true;
 
         // Debug labels: 'N' at the image's north edge (top of canvas