diff --git a/Changelog.md b/Changelog.md
index 01b831e..b5984a3 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,3 +1,8 @@
+# 0.6.6
+Update geometry lib to v0.1.5. Fix for incorrect diagonal measurement in grids (issue #3). Issue with dnd5e may still result in questionable rounded values when measuring Euclidean distances and 5/10/5 measurements on hex maps. See https://github.com/foundryvtt/dnd5e/issues/2257 and https://github.com/foundryvtt/dnd5e/issues/2256.
+Fix for updating ruler elevation label on gridless maps when increasing or decreasing elevation.
+Fix for measuring elevation for terrains created by Enhanced Terrain Elevation (issues #8, #15).
+
 # 0.6.5
 Update geometry lib to v0.1.4.
 
diff --git a/scripts/geometry b/scripts/geometry
index 69beb1a..24d14f7 160000
--- a/scripts/geometry
+++ b/scripts/geometry
@@ -1 +1 @@
-Subproject commit 69beb1a3060bfd451f717544bbc1de1af33451ea
+Subproject commit 24d14f72f2b0dbbe36fed19689e76855c1681550
diff --git a/scripts/ruler.js b/scripts/ruler.js
index 05f8cc7..0fdd8a0 100644
--- a/scripts/ruler.js
+++ b/scripts/ruler.js
@@ -152,8 +152,9 @@ export function incrementElevation() {
   ruler._userElevationIncrements += 1;
 
   // Weird, but slightly change the destination to trigger a measure
+  const destination = { x: this.destination.x, y: this.destination.y };
   this.destination.x -= 1;
-  ruler.measure(this.destination);
+  ruler.measure(destination);
 
   // Broadcast the activity (see ControlsLayer.prototype._onMouseMove)
   game.user.broadcastActivity({ ruler: ruler.toJSON() });
@@ -167,8 +168,9 @@ export function decrementElevation() {
   ruler._userElevationIncrements -= 1;
 
   // Weird, but slightly change the destination to trigger a measure
+  const destination = { x: this.destination.x, y: this.destination.y };
   this.destination.x -= 1;
-  ruler.measure(this.destination);
+  ruler.measure(destination);
 
   // Broadcast the activity (see ControlsLayer.prototype._onMouseMove)
   game.user.broadcastActivity({ ruler: ruler.toJSON() });
diff --git a/scripts/terrain_elevation.js b/scripts/terrain_elevation.js
index fd27fa0..079f0fd 100644
--- a/scripts/terrain_elevation.js
+++ b/scripts/terrain_elevation.js
@@ -185,8 +185,9 @@ function TerrainLayerElevationAtPoint({x, y}) {
   // must account for possibility of
   // TO-DO: Allow user to ignore certain terrain types?
   let terrain_max_elevation = terrains.reduce((total, t) => {
-    if ( !isFinite(t.max) ) return total;
-    return Math.max(total, t.max);
+    const elevation = t.document?.elevation;
+    if ( !isFinite(elevation) ) return total;
+    return Math.max(total, elevation);
   }, Number.NEGATIVE_INFINITY);
 
   // In case all the terrain maximums are infinite.