From 9f8e01f51331a8b3913fd5cc59d94eeaa70bbf79 Mon Sep 17 00:00:00 2001
From: Charles Richardson <charlesrichardsonusa@gmail.com>
Date: Fri, 20 Dec 2024 13:16:40 -0500
Subject: [PATCH 1/6] docs: elevation control in MapViewState

---
 modules/core/src/views/map-view.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/modules/core/src/views/map-view.ts b/modules/core/src/views/map-view.ts
index 4d80ef73cc3..201b14cc877 100644
--- a/modules/core/src/views/map-view.ts
+++ b/modules/core/src/views/map-view.ts
@@ -27,8 +27,8 @@ export type MapViewState = {
   minPitch?: number;
   /** Max pitch, default `60` */
   maxPitch?: number;
-  /** Viewport center offsets from lng, lat in meters */
-  position?: number[];
+  /** Viewport center offsets from lng, lat, and elevation in meters */
+  position?: [number, number, number];
 } & CommonViewState;
 
 export type MapViewProps = {

From e6b304d31e7d88c19946b65e93ed898e20ee8b3d Mon Sep 17 00:00:00 2001
From: Charles Richardson <charlesrichardsonusa@gmail.com>
Date: Sat, 21 Dec 2024 16:11:33 -0500
Subject: [PATCH 2/6] Add MapViewState change documentation

---
 docs/upgrade-guide.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/upgrade-guide.md b/docs/upgrade-guide.md
index 3ef720e4aa8..c24f310b9b3 100644
--- a/docs/upgrade-guide.md
+++ b/docs/upgrade-guide.md
@@ -32,6 +32,10 @@ Breaking changes:
 
 - `PointLight.attenuation` was previously ignored. To retain old behavior, use the default (`[1, 0, 0]`).
 
+### MapViewState
+
+- The `position` property changed from `number[]` to `[number, number, number]` (lat, lng, elevation).
+
 ## Upgrading to v9.0
 
 **Before you upgrade: known issues**

From 33dde585154ca09247fa79fe7a109fa78c3dff3b Mon Sep 17 00:00:00 2001
From: charlieforward9 <charlesrichardsonusa@gmail.com>
Date: Mon, 6 Jan 2025 16:14:03 -0500
Subject: [PATCH 3/6] fix: strictly include elevation in position type and docs

---
 docs/api-reference/core/globe-viewport.md              |  2 +-
 .../core/src/shaderlib/project/project-functions.ts    |  4 ++--
 modules/core/src/viewports/first-person-viewport.ts    |  2 +-
 modules/core/src/viewports/viewport.ts                 | 10 +++++-----
 modules/core/src/viewports/web-mercator-viewport.ts    |  4 ++--
 5 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/docs/api-reference/core/globe-viewport.md b/docs/api-reference/core/globe-viewport.md
index 69f29e1f4ec..0678bffee3d 100644
--- a/docs/api-reference/core/globe-viewport.md
+++ b/docs/api-reference/core/globe-viewport.md
@@ -64,7 +64,7 @@ Projects world coordinates to pixel coordinates on screen.
 
 Parameters:
 
-* `coordinates` (number[]) - `[longitude, latitude, altitude]`. `altitude` is in meters and default to `0` if not supplied.
+* `coordinates` ([number, number, number]) - `[longitude, latitude, altitude]`. `altitude` is in meters and default to `0` if not supplied.
 * `opts` (object)
   + `topLeft` (boolean, optional) - Whether projected coords are top left. Default to `true`.
 
diff --git a/modules/core/src/shaderlib/project/project-functions.ts b/modules/core/src/shaderlib/project/project-functions.ts
index bc66d1498c1..86362dc8258 100644
--- a/modules/core/src/shaderlib/project/project-functions.ts
+++ b/modules/core/src/shaderlib/project/project-functions.ts
@@ -81,7 +81,7 @@ function normalizeParameters(opts: {
 
 /** Get the common space position from world coordinates in the given coordinate system */
 export function getWorldPosition(
-  position: number[],
+  position: [number, number, number],
   {
     viewport,
     modelMatrix,
@@ -134,7 +134,7 @@ export function getWorldPosition(
  * a reference coordinate system
  */
 export function projectPosition(
-  position: number[],
+  position: [number, number, number],
   params: {
     /** The current viewport */
     viewport: Viewport;
diff --git a/modules/core/src/viewports/first-person-viewport.ts b/modules/core/src/viewports/first-person-viewport.ts
index 41d709ac2d5..a60a71f76ef 100644
--- a/modules/core/src/viewports/first-person-viewport.ts
+++ b/modules/core/src/viewports/first-person-viewport.ts
@@ -21,7 +21,7 @@ export type FirstPersonViewportOptions = {
   longitude?: number;
   /** Latitude of the camera, in the geospatial case. */
   latitude?: number;
-  /** Meter offsets of the camera from the lng-lat anchor point. Default `[0, 0, 0]`. */
+  /** Meter offsets of the camera from the lng-lat-elevation anchor point. Default `[0, 0, 0]`. */
   position?: [number, number, number];
   /** Bearing (heading) of the camera in degrees. Default `0` (north). */
   bearing?: number;
diff --git a/modules/core/src/viewports/viewport.ts b/modules/core/src/viewports/viewport.ts
index 05597627ce3..7d9777b9450 100644
--- a/modules/core/src/viewports/viewport.ts
+++ b/modules/core/src/viewports/viewport.ts
@@ -45,8 +45,8 @@ export type ViewportOptions = {
   longitude?: number;
   /** Latitude in degrees (geospatial only) */
   latitude?: number;
-  /** Viewport center in world space. If geospatial, refers to meter offsets from lng, lat */
-  position?: number[];
+  /** Viewport center in world space. If geospatial, refers to meter offsets from lng, lat, elevation */
+  position?: [number, number, number];
   /** Zoom level */
   zoom?: number;
   /** Padding around the viewport, in pixels. */
@@ -76,7 +76,7 @@ const DEGREES_TO_RADIANS = Math.PI / 180;
 
 const IDENTITY = createMat4();
 
-const ZERO_VECTOR = [0, 0, 0];
+const ZERO_VECTOR: [number, number, number] = [0, 0, 0];
 
 const DEFAULT_DISTANCE_SCALES: DistanceScales = {
   unitsPerMeter: [1, 1, 1],
@@ -138,7 +138,7 @@ export default class Viewport {
   isGeospatial: boolean;
   zoom: number;
   focalDistance: number;
-  position: number[];
+  position: [number, number, number];
   modelMatrix: number[] | null;
 
   /** Derived parameters */
@@ -149,7 +149,7 @@ export default class Viewport {
   distanceScales: DistanceScales; /** scale factors between world space and common space */
   scale!: number; /** scale factor, equals 2^zoom */
   center!: number[]; /** viewport center in common space */
-  cameraPosition!: number[]; /** Camera position in common space */
+  cameraPosition!: [number, number, number]; /** Camera position in common space */
   projectionMatrix!: number[];
   viewMatrix!: number[];
   viewMatrixUncentered!: number[];
diff --git a/modules/core/src/viewports/web-mercator-viewport.ts b/modules/core/src/viewports/web-mercator-viewport.ts
index 55dc1c360f7..453894859e2 100644
--- a/modules/core/src/viewports/web-mercator-viewport.ts
+++ b/modules/core/src/viewports/web-mercator-viewport.ts
@@ -44,8 +44,8 @@ export type WebMercatorViewportOptions = {
   altitude?: number;
   /** Camera fovy in degrees. If provided, overrides `altitude` */
   fovy?: number;
-  /** Viewport center in world space. If geospatial, refers to meter offsets from lng, lat */
-  position?: number[];
+  /** Viewport center in world space. If geospatial, refers to meter offsets from lng, lat, elevation */
+  position?: [number, number, number];
   /** Zoom level */
   zoom?: number;
   /** Padding around the viewport, in pixels. */

From 9d8647abefe8771d1ce733c428732333e5560b88 Mon Sep 17 00:00:00 2001
From: Charles Richardson <charlesrichardsonusa@gmail.com>
Date: Mon, 6 Jan 2025 16:56:30 -0500
Subject: [PATCH 4/6] docs: ViewportOptions position type change

---
 docs/upgrade-guide.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/upgrade-guide.md b/docs/upgrade-guide.md
index 28c4f8619a0..d57e5827214 100644
--- a/docs/upgrade-guide.md
+++ b/docs/upgrade-guide.md
@@ -32,7 +32,7 @@ Breaking changes:
 
 - `PointLight.attenuation` was previously ignored. To retain old behavior, use the default (`[1, 0, 0]`).
 
-### MapViewState
+### MapViewState / ViewportOptions
 
 - The `position` property changed from `number[]` to `[number, number, number]` (lat, lng, elevation).
 

From 5c144634787f49d3f12793a4dc37fca008615107 Mon Sep 17 00:00:00 2001
From: charlieforward9 <charlesrichardsonusa@gmail.com>
Date: Wed, 8 Jan 2025 13:58:13 -0500
Subject: [PATCH 5/6] fix: enforce 3D coordinates across dependent modules

---
 .../src/contour-layer/contour-layer.ts        |  9 ++-
 .../src/grid-layer/grid-layer.ts              |  9 ++-
 .../src/heatmap-layer/heatmap-layer.ts        | 17 +++---
 .../src/hexagon-layer/hexagon-layer.ts        |  9 ++-
 .../screen-grid-layer/screen-grid-layer.ts    |  2 +-
 modules/core/src/lib/layer.ts                 |  8 +--
 modules/core/src/lib/picking/pick-info.ts     |  4 +-
 modules/core/src/lib/view-manager.ts          | 12 ++--
 .../shaderlib/project/project-functions.ts    |  2 +-
 .../src/transitions/linear-interpolator.ts    |  6 +-
 modules/core/src/viewports/globe-viewport.ts  | 30 +++++-----
 modules/core/src/viewports/orbit-viewport.ts  |  2 +-
 .../src/viewports/orthographic-viewport.ts    | 12 ++--
 modules/core/src/viewports/viewport.ts        | 57 ++++++++++---------
 .../src/viewports/web-mercator-viewport.ts    | 10 ++--
 .../extensions/src/brushing/shader-module.ts  |  7 +--
 .../extensions/src/terrain/terrain-cover.ts   | 12 +++-
 .../extensions/src/utils/projection-utils.ts  | 16 ++++--
 .../src/h3-layers/h3-hexagon-layer.ts         |  2 +-
 .../src/tile-3d-layer/tile-3d-layer.ts        |  2 +-
 .../src/tileset-2d/tile-2d-traversal.ts       | 12 ++--
 modules/geo-layers/src/tileset-2d/utils.ts    | 12 ++--
 modules/google-maps/src/utils.ts              |  2 +-
 .../solid-polygon-layer.ts                    |  7 ++-
 24 files changed, 149 insertions(+), 112 deletions(-)

diff --git a/modules/aggregation-layers/src/contour-layer/contour-layer.ts b/modules/aggregation-layers/src/contour-layer/contour-layer.ts
index ded0d2acd82..9952ca64068 100644
--- a/modules/aggregation-layers/src/contour-layer/contour-layer.ts
+++ b/modules/aggregation-layers/src/contour-layer/contour-layer.ts
@@ -143,7 +143,7 @@ export default class GridLayer<DataT = any, ExtraPropsT extends {} = {}> extends
           getValue: ({positions}: {positions: number[]}, index: number, opts: BinOptions) => {
             const viewport = this.state.aggregatorViewport;
             // project to common space
-            const p = viewport.projectPosition(positions);
+            const p = viewport.projectPosition([positions[0], positions[1], positions[2] || 0]);
             const {cellSizeCommon, cellOriginCommon} = opts;
             return [
               Math.floor((p[0] - cellOriginCommon[0]) / cellSizeCommon[0]),
@@ -241,7 +241,10 @@ export default class GridLayer<DataT = any, ExtraPropsT extends {} = {}> extends
     let viewport = this.context.viewport;
 
     if (bounds && Number.isFinite(bounds[0][0])) {
-      let centroid = [(bounds[0][0] + bounds[1][0]) / 2, (bounds[0][1] + bounds[1][1]) / 2];
+      let centroid: [number, number] = [
+        (bounds[0][0] + bounds[1][0]) / 2,
+        (bounds[0][1] + bounds[1][1]) / 2
+      ];
       const {cellSize, gridOrigin} = this.props;
       const {unitsPerMeter} = viewport.getDistanceScales(centroid);
       cellSizeCommon[0] = unitsPerMeter[0] * cellSize;
@@ -272,7 +275,7 @@ export default class GridLayer<DataT = any, ExtraPropsT extends {} = {}> extends
       binIdRange = getBinIdRange({
         dataBounds: bounds,
         getBinId: (p: number[]) => {
-          const positionCommon = viewport.projectFlat(p);
+          const positionCommon = viewport.projectFlat([p[0], p[1]]);
           return [
             Math.floor((positionCommon[0] - cellOriginCommon[0]) / cellSizeCommon[0]),
             Math.floor((positionCommon[1] - cellOriginCommon[1]) / cellSizeCommon[1])
diff --git a/modules/aggregation-layers/src/grid-layer/grid-layer.ts b/modules/aggregation-layers/src/grid-layer/grid-layer.ts
index f0b82e8028b..ed37da97358 100644
--- a/modules/aggregation-layers/src/grid-layer/grid-layer.ts
+++ b/modules/aggregation-layers/src/grid-layer/grid-layer.ts
@@ -313,7 +313,7 @@ export default class GridLayer<DataT = any, ExtraPropsT extends {} = {}> extends
             }
             const viewport = this.state.aggregatorViewport;
             // project to common space
-            const p = viewport.projectPosition(positions);
+            const p = viewport.projectPosition([positions[0], positions[1], positions[2] || 0]);
             const {cellSizeCommon, cellOriginCommon} = opts;
             return [
               Math.floor((p[0] - cellOriginCommon[0]) / cellSizeCommon[0]),
@@ -446,7 +446,10 @@ export default class GridLayer<DataT = any, ExtraPropsT extends {} = {}> extends
     let viewport = this.context.viewport;
 
     if (bounds && Number.isFinite(bounds[0][0])) {
-      let centroid = [(bounds[0][0] + bounds[1][0]) / 2, (bounds[0][1] + bounds[1][1]) / 2];
+      let centroid: [number, number] = [
+        (bounds[0][0] + bounds[1][0]) / 2,
+        (bounds[0][1] + bounds[1][1]) / 2
+      ];
       const {cellSize} = this.props;
       const {unitsPerMeter} = viewport.getDistanceScales(centroid);
       cellSizeCommon[0] = unitsPerMeter[0] * cellSize;
@@ -475,7 +478,7 @@ export default class GridLayer<DataT = any, ExtraPropsT extends {} = {}> extends
       binIdRange = getBinIdRange({
         dataBounds: bounds,
         getBinId: (p: number[]) => {
-          const positionCommon = viewport.projectFlat(p);
+          const positionCommon = viewport.projectFlat([p[0], p[1]]);
           return [
             Math.floor((positionCommon[0] - cellOriginCommon[0]) / cellSizeCommon[0]),
             Math.floor((positionCommon[1] - cellOriginCommon[1]) / cellSizeCommon[1])
diff --git a/modules/aggregation-layers/src/heatmap-layer/heatmap-layer.ts b/modules/aggregation-layers/src/heatmap-layer/heatmap-layer.ts
index a1ad95b8d53..bbed01c8d9c 100644
--- a/modules/aggregation-layers/src/heatmap-layer/heatmap-layer.ts
+++ b/modules/aggregation-layers/src/heatmap-layer/heatmap-layer.ts
@@ -492,10 +492,10 @@ export default class HeatmapLayer<
     // Unproject all 4 corners of the current screen coordinates into world coordinates (lng/lat)
     // Takes care of viewport has non zero bearing/pitch (i.e axis not aligned with world coordiante system)
     const viewportCorners = [
-      viewport.unproject([0, 0]),
-      viewport.unproject([viewport.width, 0]),
-      viewport.unproject([0, viewport.height]),
-      viewport.unproject([viewport.width, viewport.height])
+      viewport.unproject([0, 0, 0]),
+      viewport.unproject([viewport.width, 0, 0]),
+      viewport.unproject([0, viewport.height, 0]),
+      viewport.unproject([viewport.width, viewport.height, 0])
     ].map(p => p.map(Math.fround));
 
     // #1: get world bounds for current viewport extends
@@ -546,7 +546,10 @@ export default class HeatmapLayer<
     triPositionBuffer!.write(packVertices(viewportCorners, 3));
 
     const textureBounds = viewportCorners.map(p =>
-      getTextureCoordinates(viewport.projectPosition(p), normalizedCommonBounds!)
+      getTextureCoordinates(
+        viewport.projectPosition([p[0], p[1], p[2] || 0]),
+        normalizedCommonBounds!
+      )
     );
     triTexCoordBuffer!.write(packVertices(textureBounds, 2));
   }
@@ -691,8 +694,8 @@ export default class HeatmapLayer<
   _commonToWorldBounds(commonBounds) {
     const [xMin, yMin, xMax, yMax] = commonBounds;
     const {viewport} = this.context;
-    const bottomLeftWorld = viewport.unprojectPosition([xMin, yMin]);
-    const topRightWorld = viewport.unprojectPosition([xMax, yMax]);
+    const bottomLeftWorld = viewport.unprojectPosition([xMin, yMin, 0]);
+    const topRightWorld = viewport.unprojectPosition([xMax, yMax, 0]);
 
     return bottomLeftWorld.slice(0, 2).concat(topRightWorld.slice(0, 2));
   }
diff --git a/modules/aggregation-layers/src/hexagon-layer/hexagon-layer.ts b/modules/aggregation-layers/src/hexagon-layer/hexagon-layer.ts
index 0be249804d7..f4bcbee31db 100644
--- a/modules/aggregation-layers/src/hexagon-layer/hexagon-layer.ts
+++ b/modules/aggregation-layers/src/hexagon-layer/hexagon-layer.ts
@@ -317,7 +317,7 @@ export default class HexagonLayer<
             }
             const viewport = this.state.aggregatorViewport;
             // project to common space
-            const p = viewport.projectPosition(positions);
+            const p = viewport.projectPosition([positions[0], positions[1], positions[2] || 0]);
             const {radiusCommon, hexOriginCommon} = opts;
             return pointToHexbin(
               [p[0] - hexOriginCommon[0], p[1] - hexOriginCommon[1]],
@@ -451,7 +451,10 @@ export default class HexagonLayer<
     let viewport = this.context.viewport;
 
     if (bounds && Number.isFinite(bounds[0][0])) {
-      let centroid = [(bounds[0][0] + bounds[1][0]) / 2, (bounds[0][1] + bounds[1][1]) / 2];
+      let centroid: [number, number] = [
+        (bounds[0][0] + bounds[1][0]) / 2,
+        (bounds[0][1] + bounds[1][1]) / 2
+      ];
       const {radius} = this.props;
       const {unitsPerMeter} = viewport.getDistanceScales(centroid);
       radiusCommon = unitsPerMeter[0] * radius;
@@ -474,7 +477,7 @@ export default class HexagonLayer<
       binIdRange = getBinIdRange({
         dataBounds: bounds,
         getBinId: (p: number[]) => {
-          const positionCommon = viewport.projectFlat(p);
+          const positionCommon = viewport.projectFlat([p[0], p[1]]);
           positionCommon[0] -= hexOriginCommon[0];
           positionCommon[1] -= hexOriginCommon[1];
           return pointToHexbin(positionCommon, radiusCommon);
diff --git a/modules/aggregation-layers/src/screen-grid-layer/screen-grid-layer.ts b/modules/aggregation-layers/src/screen-grid-layer/screen-grid-layer.ts
index 0be80371606..4f2c3edd55f 100644
--- a/modules/aggregation-layers/src/screen-grid-layer/screen-grid-layer.ts
+++ b/modules/aggregation-layers/src/screen-grid-layer/screen-grid-layer.ts
@@ -138,7 +138,7 @@ export default class ScreenGridLayer<
           sources: ['positions'],
           getValue: ({positions}: {positions: number[]}, index: number, opts: BinOptions) => {
             const viewport = this.context.viewport;
-            const p = viewport.project(positions);
+            const p = viewport.project([positions[0], positions[1], positions[2] || 0]);
             const cellSizePixels: number = opts.cellSizePixels;
             if (p[0] < 0 || p[0] >= viewport.width || p[1] < 0 || p[1] >= viewport.height) {
               // Not on screen
diff --git a/modules/core/src/lib/layer.ts b/modules/core/src/lib/layer.ts
index 04e16aa177b..31730d50f48 100644
--- a/modules/core/src/lib/layer.ts
+++ b/modules/core/src/lib/layer.ts
@@ -219,7 +219,7 @@ export default abstract class Layer<PropsT extends {} = {}> extends Component<
   // Public API for users
 
   /** Projects a point with current view state from the current layer's coordinate system to screen */
-  project(xyz: number[]): number[] {
+  project(xyz: [number, number, number]): [number, number, number] {
     assert(this.internalState);
     const viewport = this.internalState.viewport || this.context.viewport;
 
@@ -230,12 +230,12 @@ export default abstract class Layer<PropsT extends {} = {}> extends Component<
       coordinateSystem: this.props.coordinateSystem
     });
     const [x, y, z] = worldToPixels(worldPosition, viewport.pixelProjectionMatrix);
-    return xyz.length === 2 ? [x, y] : [x, y, z];
+    return [x, y, z];
   }
 
   /** Unprojects a screen pixel to the current view's default coordinate system
       Note: this does not reverse `project`. */
-  unproject(xy: number[]): number[] {
+  unproject(xy: [number, number, number]): [number, number, number] {
     assert(this.internalState);
     const viewport = this.internalState.viewport || this.context.viewport;
     return viewport.unproject(xy);
@@ -243,7 +243,7 @@ export default abstract class Layer<PropsT extends {} = {}> extends Component<
 
   /** Projects a point with current view state from the current layer's coordinate system to the world space */
   projectPosition(
-    xyz: number[],
+    xyz: [number, number, number],
     params?: {
       /** The viewport to use */
       viewport?: Viewport;
diff --git a/modules/core/src/lib/picking/pick-info.ts b/modules/core/src/lib/picking/pick-info.ts
index 4a1d36bb379..ae13a02f2f1 100644
--- a/modules/core/src/lib/picking/pick-info.ts
+++ b/modules/core/src/lib/picking/pick-info.ts
@@ -53,9 +53,9 @@ export function getEmptyPickingInfo({
     // Find the viewport that contain the picked pixel
     pickedViewport = getViewportFromCoordinates(pickInfo?.pickedViewports || viewports, {x, y});
   }
-  let coordinate: number[] | undefined;
+  let coordinate: [number, number, number] | undefined;
   if (pickedViewport) {
-    const point = [x - pickedViewport.x, y - pickedViewport.y];
+    const point: [number, number, number] = [x - pickedViewport.x, y - pickedViewport.y, 0];
     if (z !== undefined) {
       point[2] = z;
     }
diff --git a/modules/core/src/lib/view-manager.ts b/modules/core/src/lib/view-manager.ts
index 8d68f61aebd..d53771a7f76 100644
--- a/modules/core/src/lib/view-manager.ts
+++ b/modules/core/src/lib/view-manager.ts
@@ -20,14 +20,14 @@ type ViewStateOf<ViewT> = ViewT extends View<infer ViewStateT> ? ViewStateT : ne
 type OneOfViews<ViewsT extends ViewOrViews> = ViewsT extends null
   ? MapView
   : ViewsT extends View[]
-    ? ViewsT[number]
-    : ViewsT;
+  ? ViewsT[number]
+  : ViewsT;
 export type AnyViewStateOf<ViewsT extends ViewOrViews> = ViewStateOf<OneOfViews<ViewsT>>;
 export type ViewStateMap<ViewsT extends ViewOrViews> = ViewsT extends null
   ? MapViewState
   : ViewsT extends View
-    ? ViewStateOf<ViewsT>
-    : {[viewId: string]: AnyViewStateOf<ViewsT>};
+  ? ViewStateOf<ViewsT>
+  : {[viewId: string]: AnyViewStateOf<ViewsT>};
 
 /** This is a very lose type of all "acceptable" viewState
  * It's not good for type hinting but matches what may exist internally
@@ -195,13 +195,13 @@ export default class ViewManager<ViewsT extends View[]> {
    * @param {Object} opts.topLeft=true - Whether origin is top left
    * @return {Array|null} - [lng, lat, Z] or [X, Y, Z]
    */
-  unproject(xyz: number[], opts?: {topLeft?: boolean}): number[] | null {
+  unproject(xyz: [number, number, number], opts?: {topLeft?: boolean}): number[] | null {
     const viewports = this.getViewports();
     const pixel = {x: xyz[0], y: xyz[1]};
     for (let i = viewports.length - 1; i >= 0; --i) {
       const viewport = viewports[i];
       if (viewport.containsPixel(pixel)) {
-        const p = xyz.slice();
+        const p = xyz.slice() as [number, number, number];
         p[0] -= viewport.x;
         p[1] -= viewport.y;
         return viewport.unproject(p, opts);
diff --git a/modules/core/src/shaderlib/project/project-functions.ts b/modules/core/src/shaderlib/project/project-functions.ts
index 86362dc8258..8936ce04a4e 100644
--- a/modules/core/src/shaderlib/project/project-functions.ts
+++ b/modules/core/src/shaderlib/project/project-functions.ts
@@ -17,7 +17,7 @@ import type {CoordinateSystem} from '../../lib/constants';
 import type Viewport from '../../viewports/viewport';
 import type {NumericArray} from '../../types/types';
 
-const DEFAULT_COORDINATE_ORIGIN = [0, 0, 0];
+const DEFAULT_COORDINATE_ORIGIN: [number, number, number] = [0, 0, 0];
 
 // In project.glsl, offset modes calculate z differently from LNG_LAT mode.
 // offset modes apply the y adjustment (unitsPerMeter2) when projecting z
diff --git a/modules/core/src/transitions/linear-interpolator.ts b/modules/core/src/transitions/linear-interpolator.ts
index b064b9a743b..84477c9e0b3 100644
--- a/modules/core/src/transitions/linear-interpolator.ts
+++ b/modules/core/src/transitions/linear-interpolator.ts
@@ -11,7 +11,7 @@ const DEFAULT_PROPS = ['longitude', 'latitude', 'zoom', 'bearing', 'pitch'];
 const DEFAULT_REQUIRED_PROPS = ['longitude', 'latitude', 'zoom'];
 
 type PropsWithAnchor = {
-  around?: number[];
+  around?: [number, number, number];
   aroundPosition?: number[];
   [key: string]: any;
 };
@@ -21,7 +21,7 @@ type PropsWithAnchor = {
  */
 export default class LinearInterpolator extends TransitionInterpolator {
   opts: {
-    around?: number[];
+    around?: [number, number, number];
     makeViewport?: (props: Record<string, any>) => Viewport;
   };
 
@@ -42,7 +42,7 @@ export default class LinearInterpolator extends TransitionInterpolator {
                 extract?: string[];
                 required?: string[];
               };
-          around?: number[];
+          around?: [number, number, number];
           makeViewport?: (props: Record<string, any>) => Viewport;
         } = {}
   ) {
diff --git a/modules/core/src/viewports/globe-viewport.ts b/modules/core/src/viewports/globe-viewport.ts
index 1d7657dd7e5..1fa011d1502 100644
--- a/modules/core/src/viewports/globe-viewport.ts
+++ b/modules/core/src/viewports/globe-viewport.ts
@@ -47,7 +47,7 @@ export type GlobeViewportOptions = {
   /** Camera altitude relative to the viewport height, used to control the FOV. Default `1.5` */
   altitude?: number;
   /* Meter offsets of the viewport center from lng, lat */
-  position?: number[];
+  position?: [number, number, number];
   /** Zoom level */
   zoom?: number;
   /** Use orthographic projection */
@@ -138,10 +138,10 @@ export default class GlobeViewport extends Viewport {
   getBounds(options: {z?: number} = {}): [number, number, number, number] {
     const unprojectOption = {targetZ: options.z || 0};
 
-    const left = this.unproject([0, this.height / 2], unprojectOption);
-    const top = this.unproject([this.width / 2, 0], unprojectOption);
-    const right = this.unproject([this.width, this.height / 2], unprojectOption);
-    const bottom = this.unproject([this.width / 2, this.height], unprojectOption);
+    const left = this.unproject([0, this.height / 2, 0], unprojectOption);
+    const top = this.unproject([this.width / 2, 0, 0], unprojectOption);
+    const right = this.unproject([this.width, this.height / 2, 0], unprojectOption);
+    const bottom = this.unproject([this.width / 2, this.height, 0], unprojectOption);
 
     if (right[0] < this.longitude) right[0] += 360;
     if (left[0] > this.longitude) left[0] -= 360;
@@ -155,9 +155,9 @@ export default class GlobeViewport extends Viewport {
   }
 
   unproject(
-    xyz: number[],
+    xyz: [number, number, number],
     {topLeft = true, targetZ}: {topLeft?: boolean; targetZ?: number} = {}
-  ): number[] {
+  ): [number, number, number] {
     const [x, y, z] = xyz;
 
     const y2 = topLeft ? y : this.height - y;
@@ -190,10 +190,10 @@ export default class GlobeViewport extends Viewport {
     if (Number.isFinite(z)) {
       return [X, Y, Z];
     }
-    return Number.isFinite(targetZ) ? [X, Y, targetZ as number] : [X, Y];
+    return Number.isFinite(targetZ) ? [X, Y, targetZ as number] : [X, Y, 0];
   }
 
-  projectPosition(xyz: number[]): [number, number, number] {
+  projectPosition(xyz: [number, number, number]): [number, number, number] {
     const [lng, lat, Z = 0] = xyz;
     const lambda = lng * DEGREES_TO_RADIANS;
     const phi = lat * DEGREES_TO_RADIANS;
@@ -203,7 +203,7 @@ export default class GlobeViewport extends Viewport {
     return [Math.sin(lambda) * cosPhi * D, -Math.cos(lambda) * cosPhi * D, Math.sin(phi) * D];
   }
 
-  unprojectPosition(xyz: number[]): [number, number, number] {
+  unprojectPosition(xyz: [number, number, number]): [number, number, number] {
     const [x, y, z] = xyz;
     const D = vec3.len(xyz);
     const phi = Math.asin(z / D);
@@ -215,15 +215,15 @@ export default class GlobeViewport extends Viewport {
     return [lng, lat, Z];
   }
 
-  projectFlat(xyz: number[]): [number, number] {
-    return xyz as [number, number];
+  projectFlat(xy: [number, number]): [number, number] {
+    return xy;
   }
 
-  unprojectFlat(xyz: number[]): [number, number] {
-    return xyz as [number, number];
+  unprojectFlat(xy: [number, number]): [number, number] {
+    return xy;
   }
 
-  panByPosition(coords: number[], pixel: number[]): GlobeViewportOptions {
+  panByPosition(coords: number[], pixel: [number, number, number]): GlobeViewportOptions {
     const fromPosition = this.unproject(pixel);
     return {
       longitude: coords[0] - fromPosition[0] + this.longitude,
diff --git a/modules/core/src/viewports/orbit-viewport.ts b/modules/core/src/viewports/orbit-viewport.ts
index 333f6afaaf4..3c8c159b32d 100644
--- a/modules/core/src/viewports/orbit-viewport.ts
+++ b/modules/core/src/viewports/orbit-viewport.ts
@@ -136,7 +136,7 @@ export default class OrbitViewport extends Viewport {
     return [X, Y, Z];
   }
 
-  panByPosition(coords: number[], pixel: number[]): OrbitViewportOptions {
+  panByPosition(coords: [number, number, number], pixel: number[]): OrbitViewportOptions {
     const p0 = this.project(coords);
     const nextCenter = [
       this.width / 2 + p0[0] - pixel[0],
diff --git a/modules/core/src/viewports/orthographic-viewport.ts b/modules/core/src/viewports/orthographic-viewport.ts
index c97635c339a..96c008fe2fc 100644
--- a/modules/core/src/viewports/orthographic-viewport.ts
+++ b/modules/core/src/viewports/orthographic-viewport.ts
@@ -60,7 +60,7 @@ export type OrthographicViewportOptions = {
   /** Viewport height in pixels */
   height?: number;
   /** The world position at the center of the viewport. Default `[0, 0, 0]`. */
-  target?: [number, number, number] | [number, number];
+  target?: [number, number, number];
   /**  The zoom level of the viewport. `zoom: 0` maps one unit distance to one pixel on screen, and increasing `zoom` by `1` scales the same object to twice as large.
    *   To apply independent zoom levels to the X and Y axes, supply an array `[zoomX, zoomY]`. Default `0`. */
   zoom?: number | [number, number];
@@ -121,24 +121,24 @@ export default class OrthographicViewport extends Viewport {
     });
   }
 
-  projectFlat([X, Y]: number[]): [number, number] {
+  projectFlat([X, Y]: [number, number]): [number, number] {
     const {unitsPerMeter} = this.distanceScales;
     return [X * unitsPerMeter[0], Y * unitsPerMeter[1]];
   }
 
-  unprojectFlat([x, y]: number[]): [number, number] {
+  unprojectFlat([x, y]: [number, number]): [number, number] {
     const {metersPerUnit} = this.distanceScales;
     return [x * metersPerUnit[0], y * metersPerUnit[1]];
   }
 
   /* Needed by LinearInterpolator */
-  panByPosition(coords: number[], pixel: number[]): OrthographicViewportOptions {
+  panByPosition(coords: [number, number], pixel: number[]): OrthographicViewportOptions {
     const fromLocation = pixelsToWorld(pixel, this.pixelUnprojectionMatrix);
     const toLocation = this.projectFlat(coords);
 
     const translate = vec2.add([], toLocation, vec2.negate([], fromLocation));
     const newCenter = vec2.add([], this.center, translate);
-
-    return {target: this.unprojectFlat(newCenter)};
+    const target = this.unprojectFlat(newCenter);
+    return {target: [target[0], target[1], 0]};
   }
 }
diff --git a/modules/core/src/viewports/viewport.ts b/modules/core/src/viewports/viewport.ts
index 7d9777b9450..f60725f6536 100644
--- a/modules/core/src/viewports/viewport.ts
+++ b/modules/core/src/viewports/viewport.ts
@@ -148,7 +148,7 @@ export default class Viewport {
 
   distanceScales: DistanceScales; /** scale factors between world space and common space */
   scale!: number; /** scale factor, equals 2^zoom */
-  center!: number[]; /** viewport center in common space */
+  center!: [number, number, number]; /** viewport center in common space */
   cameraPosition!: [number, number, number]; /** Camera position in common space */
   projectionMatrix!: number[];
   viewMatrix!: number[];
@@ -234,22 +234,21 @@ export default class Viewport {
   /**
    * Projects xyz (possibly latitude and longitude) to pixel coordinates in window
    * using viewport projection parameters
-   * - [longitude, latitude] to [x, y]
    * - [longitude, latitude, Z] => [x, y, z]
    * Note: By default, returns top-left coordinates for canvas/SVG type render
    *
-   * @param {Array} lngLatZ - [lng, lat] or [lng, lat, Z]
+   * @param {Array} xyz - [lng, lat, Z]
    * @param {Object} opts - options
    * @param {Object} opts.topLeft=true - Whether projected coords are top left
    * @return {Array} - [x, y] or [x, y, z] in top left coords
    */
-  project(xyz: number[], {topLeft = true}: {topLeft?: boolean} = {}): number[] {
+  project(xyz: [number, number, number], {topLeft = true}: {topLeft?: boolean} = {}): number[] {
     const worldPosition = this.projectPosition(xyz);
     const coord = worldToPixels(worldPosition, this.pixelProjectionMatrix);
 
     const [x, y] = coord;
     const y2 = topLeft ? y : this.height - y;
-    return xyz.length === 2 ? [x, y2] : [x, y2, coord[2]];
+    return [x, y2, coord[2]];
   }
 
   /**
@@ -263,33 +262,37 @@ export default class Viewport {
    * @return {Array|null} - [lng, lat, Z] or [X, Y, Z]
    */
   unproject(
-    xyz: number[],
+    xyz: [number, number, number],
     {topLeft = true, targetZ}: {topLeft?: boolean; targetZ?: number} = {}
-  ): number[] {
+  ): [number, number, number] {
     const [x, y, z] = xyz;
 
     const y2 = topLeft ? y : this.height - y;
     const targetZWorld = targetZ && targetZ * this.distanceScales.unitsPerMeter[2];
-    const coord = pixelsToWorld([x, y2, z], this.pixelUnprojectionMatrix, targetZWorld);
+    const coord = pixelsToWorld([x, y2, z], this.pixelUnprojectionMatrix, targetZWorld) as [
+      number,
+      number,
+      number
+    ];
     const [X, Y, Z] = this.unprojectPosition(coord);
 
     if (Number.isFinite(z)) {
       return [X, Y, Z];
     }
-    return Number.isFinite(targetZ) ? [X, Y, targetZ as number] : [X, Y];
+    return [X, Y, targetZ as number];
   }
 
   // NON_LINEAR PROJECTION HOOKS
   // Used for web meractor projection
 
-  projectPosition(xyz: number[]): [number, number, number] {
-    const [X, Y] = this.projectFlat(xyz);
+  projectPosition(xyz: [number, number, number]): [number, number, number] {
+    const [X, Y] = this.projectFlat([xyz[0], xyz[1]]);
     const Z = (xyz[2] || 0) * this.distanceScales.unitsPerMeter[2];
     return [X, Y, Z];
   }
 
-  unprojectPosition(xyz: number[]): [number, number, number] {
-    const [X, Y] = this.unprojectFlat(xyz);
+  unprojectPosition(xyz: [number, number, number]): [number, number, number] {
+    const [X, Y] = this.unprojectFlat([xyz[0], xyz[1]]);
     const Z = (xyz[2] || 0) * this.distanceScales.metersPerUnit[2];
     return [X, Y, Z];
   }
@@ -303,16 +306,16 @@ export default class Viewport {
    *   Specifies a point on the sphere to project onto the map.
    * @return {Array} [x,y] coordinates.
    */
-  projectFlat(xyz: number[]): [number, number] {
+  projectFlat(xy: [number, number]): [number, number] {
     if (this.isGeospatial) {
       // Shader clamps latitude to +-89.9, see /shaderlib/project/project.glsl.js
       // lngLatToWorld([0, -89.9])[1] = -317.9934163758329
       // lngLatToWorld([0, 89.9])[1] = 829.9934163758271
-      const result = lngLatToWorld(xyz);
+      const result = lngLatToWorld(xy);
       result[1] = clamp(result[1], -318, 830);
-      return result;
+      return [result[0], result[1]];
     }
-    return xyz as [number, number];
+    return xy;
   }
 
   /**
@@ -323,11 +326,11 @@ export default class Viewport {
    *   Has toArray method if you need a GeoJSON Array.
    *   Per cartographic tradition, lat and lon are specified as degrees.
    */
-  unprojectFlat(xyz: number[]): [number, number] {
+  unprojectFlat(xy: [number, number]): [number, number] {
     if (this.isGeospatial) {
-      return worldToLngLat(xyz);
+      return worldToLngLat(xy);
     }
-    return xyz as [number, number];
+    return xy;
   }
 
   /**
@@ -337,10 +340,10 @@ export default class Viewport {
   getBounds(options: {z?: number} = {}): [number, number, number, number] {
     const unprojectOption = {targetZ: options.z || 0};
 
-    const topLeft = this.unproject([0, 0], unprojectOption);
-    const topRight = this.unproject([this.width, 0], unprojectOption);
-    const bottomLeft = this.unproject([0, this.height], unprojectOption);
-    const bottomRight = this.unproject([this.width, this.height], unprojectOption);
+    const topLeft = this.unproject([0, 0, 0], unprojectOption);
+    const topRight = this.unproject([this.width, 0, 0], unprojectOption);
+    const bottomLeft = this.unproject([0, this.height, 0], unprojectOption);
+    const bottomRight = this.unproject([this.width, this.height, 0], unprojectOption);
 
     return [
       Math.min(topLeft[0], topRight[0], bottomLeft[0], bottomRight[0]),
@@ -431,10 +434,10 @@ export default class Viewport {
     this.scale = scale;
 
     const {position, modelMatrix} = opts;
-    let meterOffset: number[] = ZERO_VECTOR;
+    let meterOffset: [number, number, number] = ZERO_VECTOR;
     if (position) {
       meterOffset = modelMatrix
-        ? (new Matrix4(modelMatrix).transformAsVector(position, []) as number[])
+        ? (new Matrix4(modelMatrix).transformAsVector(position, []) as [number, number, number])
         : position;
     }
 
@@ -445,7 +448,7 @@ export default class Viewport {
       this.center = new Vector3(meterOffset)
         // Convert to pixels in current zoom
         .scale(this.distanceScales.unitsPerMeter)
-        .add(center);
+        .toArray() as [number, number, number];
     } else {
       this.center = this.projectPosition(meterOffset);
     }
diff --git a/modules/core/src/viewports/web-mercator-viewport.ts b/modules/core/src/viewports/web-mercator-viewport.ts
index 453894859e2..45ec9b7f328 100644
--- a/modules/core/src/viewports/web-mercator-viewport.ts
+++ b/modules/core/src/viewports/web-mercator-viewport.ts
@@ -236,22 +236,22 @@ export default class WebMercatorViewport extends Viewport {
     return this._subViewports;
   }
 
-  projectPosition(xyz: number[]): [number, number, number] {
+  projectPosition(xyz: [number, number, number]): [number, number, number] {
     if (this._pseudoMeters) {
       // Backward compatibility
       return super.projectPosition(xyz);
     }
-    const [X, Y] = this.projectFlat(xyz);
+    const [X, Y] = this.projectFlat([xyz[0], xyz[1]]);
     const Z = (xyz[2] || 0) * unitsPerMeter(xyz[1]);
     return [X, Y, Z];
   }
 
-  unprojectPosition(xyz: number[]): [number, number, number] {
+  unprojectPosition(xyz: [number, number, number]): [number, number, number] {
     if (this._pseudoMeters) {
       // Backward compatibility
       return super.unprojectPosition(xyz);
     }
-    const [X, Y] = this.unprojectFlat(xyz);
+    const [X, Y] = this.unprojectFlat([xyz[0], xyz[1]]);
     const Z = (xyz[2] || 0) / unitsPerMeter(Y);
     return [X, Y, Z];
   }
@@ -270,7 +270,7 @@ export default class WebMercatorViewport extends Viewport {
     return addMetersToLngLat(lngLatZ, xyz);
   }
 
-  panByPosition(coords: number[], pixel: number[]): WebMercatorViewportOptions {
+  panByPosition(coords: [number, number], pixel: number[]): WebMercatorViewportOptions {
     const fromLocation = pixelsToWorld(pixel, this.pixelUnprojectionMatrix);
     const toLocation = this.projectFlat(coords);
 
diff --git a/modules/extensions/src/brushing/shader-module.ts b/modules/extensions/src/brushing/shader-module.ts
index d2a487090e8..263d7143ceb 100644
--- a/modules/extensions/src/brushing/shader-module.ts
+++ b/modules/extensions/src/brushing/shader-module.ts
@@ -129,10 +129,9 @@ export default {
       radius: brushingRadius,
       target: TARGET[brushingTarget] || 0,
       mousePos: mousePosition
-        ? (viewport.unproject([mousePosition.x - viewport.x, mousePosition.y - viewport.y]) as [
-            number,
-            number
-          ])
+        ? (viewport
+            .unproject([mousePosition.x - viewport.x, mousePosition.y - viewport.y, 0])
+            .slice(0, 2) as [number, number])
         : [0, 0]
     };
   },
diff --git a/modules/extensions/src/terrain/terrain-cover.ts b/modules/extensions/src/terrain/terrain-cover.ts
index cb39fedfb28..ef27c620047 100644
--- a/modules/extensions/src/terrain/terrain-cover.ts
+++ b/modules/extensions/src/terrain/terrain-cover.ts
@@ -117,8 +117,16 @@ export class TerrainCover {
         shouldRedraw = true;
         this.targetBounds = this.tile.boundingBox;
 
-        const bottomLeftCommon = viewport.projectPosition(this.targetBounds[0]);
-        const topRightCommon = viewport.projectPosition(this.targetBounds[1]);
+        const bottomLeftCommon = viewport.projectPosition([
+          this.targetBounds[0][0],
+          this.targetBounds[0][1],
+          this.targetBounds[0][2] || 0
+        ]);
+        const topRightCommon = viewport.projectPosition([
+          this.targetBounds[1][0],
+          this.targetBounds[1][1],
+          this.targetBounds[1][2] || 0
+        ]);
         this.targetBoundsCommon = [
           bottomLeftCommon[0],
           bottomLeftCommon[1],
diff --git a/modules/extensions/src/utils/projection-utils.ts b/modules/extensions/src/utils/projection-utils.ts
index 3d8b491ddb5..6ed485bf4dc 100644
--- a/modules/extensions/src/utils/projection-utils.ts
+++ b/modules/extensions/src/utils/projection-utils.ts
@@ -23,8 +23,14 @@ export function joinLayerBounds(
   for (const layer of layers) {
     const layerBounds = layer.getBounds();
     if (layerBounds) {
-      const bottomLeftCommon = layer.projectPosition(layerBounds[0], {viewport, autoOffset: false});
-      const topRightCommon = layer.projectPosition(layerBounds[1], {viewport, autoOffset: false});
+      const bottomLeftCommon = layer.projectPosition([layerBounds[0][0], layerBounds[0][1], 0], {
+        viewport,
+        autoOffset: false
+      });
+      const topRightCommon = layer.projectPosition([layerBounds[1][0], layerBounds[1][1], 0], {
+        viewport,
+        autoOffset: false
+      });
 
       bounds[0] = Math.min(bounds[0], bottomLeftCommon[0]);
       bounds[1] = Math.min(bounds[1], bottomLeftCommon[1]);
@@ -135,8 +141,10 @@ export function getViewportBounds(viewport: Viewport, zRange?: [number, number])
   }
 
   // Viewport bounds in cartesian coordinates
-  const viewportBottomLeftCommon = viewport.projectPosition(viewportBoundsWorld.slice(0, 2));
-  const viewportTopRightCommon = viewport.projectPosition(viewportBoundsWorld.slice(2, 4));
+  const bottomLeft = viewportBoundsWorld.slice(0, 2);
+  const topRight = viewportBoundsWorld.slice(2, 4);
+  const viewportBottomLeftCommon = viewport.projectPosition([bottomLeft[0], bottomLeft[1], 0]);
+  const viewportTopRightCommon = viewport.projectPosition([topRight[0], topRight[1], 0]);
   return [
     viewportBottomLeftCommon[0],
     viewportBottomLeftCommon[1],
diff --git a/modules/geo-layers/src/h3-layers/h3-hexagon-layer.ts b/modules/geo-layers/src/h3-layers/h3-hexagon-layer.ts
index 20220c174f1..d720c4d7031 100644
--- a/modules/geo-layers/src/h3-layers/h3-hexagon-layer.ts
+++ b/modules/geo-layers/src/h3-layers/h3-hexagon-layer.ts
@@ -211,7 +211,7 @@ export default class H3HexagonLayer<
 
     const [centerX, centerY] = viewport.projectFlat([centerLng, centerLat]);
     vertices = vertices.map(p => {
-      const worldPosition = viewport.projectFlat(p);
+      const worldPosition = viewport.projectFlat([p[0], p[1]]);
       return [
         (worldPosition[0] - centerX) / unitsPerMeter[0],
         (worldPosition[1] - centerY) / unitsPerMeter[1]
diff --git a/modules/geo-layers/src/tile-3d-layer/tile-3d-layer.ts b/modules/geo-layers/src/tile-3d-layer/tile-3d-layer.ts
index 1710e20e09e..f1df582580c 100644
--- a/modules/geo-layers/src/tile-3d-layer/tile-3d-layer.ts
+++ b/modules/geo-layers/src/tile-3d-layer/tile-3d-layer.ts
@@ -241,7 +241,7 @@ export default class Tile3DLayer<DataT = any, ExtraPropsT extends {} = {}> exten
       return;
     }
 
-    // eslint-disable-next-line @typescript-eslint/no-floating-promises
+    //@ts-expect-error Type 'Vector3' is not assignable to type '[number, number, number]'
     tileset3d.selectTiles(Object.values(viewports)).then(frameNumber => {
       const tilesetChanged = this.state.frameNumber !== frameNumber;
       if (tilesetChanged) {
diff --git a/modules/geo-layers/src/tileset-2d/tile-2d-traversal.ts b/modules/geo-layers/src/tileset-2d/tile-2d-traversal.ts
index ab3dba4ef55..2d1bde9185d 100644
--- a/modules/geo-layers/src/tileset-2d/tile-2d-traversal.ts
+++ b/modules/geo-layers/src/tileset-2d/tile-2d-traversal.ts
@@ -70,7 +70,7 @@ class OSMNode {
   // eslint-disable-next-line complexity
   update(params: {
     viewport: Viewport;
-    project: ((xyz: number[]) => number[]) | null;
+    project: ((xyz: [number, number, number]) => [number, number, number]) | null;
     cullingVolume: CullingVolume;
     elevationBounds: ZRange;
     minZ: number;
@@ -144,7 +144,7 @@ class OSMNode {
   getBoundingVolume(
     zRange: ZRange,
     worldOffset: number,
-    project: ((xyz: number[]) => number[]) | null
+    project: ((xyz: [number, number, number]) => [number, number, number]) | null
   ) {
     if (project) {
       // Custom projection
@@ -155,7 +155,11 @@ class OSMNode {
       // Convert from tile-relative coordinates to common space
       const refPointPositions: number[][] = [];
       for (const p of refPoints) {
-        const lngLat: number[] = osmTile2lngLat(this.x + p[0], this.y + p[1], this.z);
+        const lngLat: [number, number, number] = osmTile2lngLat(
+          this.x + p[0],
+          this.y + p[1],
+          this.z
+        );
         lngLat[2] = zRange[0];
         refPointPositions.push(project(lngLat));
 
@@ -190,7 +194,7 @@ export function getOSMTileIndices(
   zRange: ZRange | null,
   bounds?: Bounds
 ): TileIndex[] {
-  const project: ((xyz: number[]) => number[]) | null =
+  const project: ((xyz: [number, number, number]) => [number, number, number]) | null =
     viewport instanceof _GlobeViewport && viewport.resolution
       ? // eslint-disable-next-line @typescript-eslint/unbound-method
         viewport.projectPosition
diff --git a/modules/geo-layers/src/tileset-2d/utils.ts b/modules/geo-layers/src/tileset-2d/utils.ts
index 4de85da8edd..303e841b864 100644
--- a/modules/geo-layers/src/tileset-2d/utils.ts
+++ b/modules/geo-layers/src/tileset-2d/utils.ts
@@ -165,10 +165,10 @@ function getCullBoundsInViewport(
 
     const unprojectOption = {targetZ: z};
 
-    const topLeft = viewport.unproject([x, y], unprojectOption);
-    const topRight = viewport.unproject([x + width, y], unprojectOption);
-    const bottomLeft = viewport.unproject([x, y + height], unprojectOption);
-    const bottomRight = viewport.unproject([x + width, y + height], unprojectOption);
+    const topLeft = viewport.unproject([x, y, 0], unprojectOption);
+    const topRight = viewport.unproject([x + width, y, 0], unprojectOption);
+    const bottomLeft = viewport.unproject([x, y + height, 0], unprojectOption);
+    const bottomRight = viewport.unproject([x + width, y + height, 0], unprojectOption);
 
     return [
       Math.min(topLeft[0], topRight[0], bottomLeft[0], bottomRight[0]),
@@ -204,12 +204,12 @@ function getScale(z: number, tileSize: number): number {
 }
 
 // https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames#Lon..2Flat._to_tile_numbers_2
-export function osmTile2lngLat(x: number, y: number, z: number): [number, number] {
+export function osmTile2lngLat(x: number, y: number, z: number): [number, number, number] {
   const scale = getScale(z, TILE_SIZE);
   const lng = (x / scale) * 360 - 180;
   const n = Math.PI - (2 * Math.PI * y) / scale;
   const lat = (180 / Math.PI) * Math.atan(0.5 * (Math.exp(n) - Math.exp(-n)));
-  return [lng, lat];
+  return [lng, lat, 0];
 }
 
 function tile2XY(x: number, y: number, z: number, tileSize: number): [number, number] {
diff --git a/modules/google-maps/src/utils.ts b/modules/google-maps/src/utils.ts
index 34e4911719c..605c0e581d1 100644
--- a/modules/google-maps/src/utils.ts
+++ b/modules/google-maps/src/utils.ts
@@ -282,7 +282,7 @@ function getEventPixel(event, deck: Deck): {x: number; y: number} {
   }
   // event.pixel may not exist when clicking on a POI
   // https://developers.google.com/maps/documentation/javascript/reference/map#MouseEvent
-  const point = deck.getViewports()[0].project([event.latLng.lng(), event.latLng.lat()]);
+  const point = deck.getViewports()[0].project([event.latLng.lng(), event.latLng.lat(), 0]);
   return {
     x: point[0],
     y: point[1]
diff --git a/modules/layers/src/solid-polygon-layer/solid-polygon-layer.ts b/modules/layers/src/solid-polygon-layer/solid-polygon-layer.ts
index 675a90c6383..704741d48cd 100644
--- a/modules/layers/src/solid-polygon-layer/solid-polygon-layer.ts
+++ b/modules/layers/src/solid-polygon-layer/solid-polygon-layer.ts
@@ -160,13 +160,16 @@ export default class SolidPolygonLayer<DataT = any, ExtraPropsT extends {} = {}>
       coordinateSystem = COORDINATE_SYSTEM.LNGLAT;
     }
 
-    let preproject: ((xy: number[]) => number[]) | undefined;
+    let preproject: ((xyz: [number, number, number]) => number[]) | undefined;
 
     if (coordinateSystem === COORDINATE_SYSTEM.LNGLAT) {
       if (_full3d) {
         preproject = viewport.projectPosition.bind(viewport);
       } else {
-        preproject = viewport.projectFlat.bind(viewport);
+        preproject = (xyz: [number, number, number]) => {
+          const [x, y] = viewport.projectFlat([xyz[0], xyz[1]]);
+          return [x, y, 0];
+        };
       }
     }
 

From a8117e5a7ac5ac0214d913c339ff570e37af3f86 Mon Sep 17 00:00:00 2001
From: charlieforward9 <charlesrichardsonusa@gmail.com>
Date: Wed, 8 Jan 2025 14:01:34 -0500
Subject: [PATCH 6/6] fix: coordinate ordering

---
 docs/upgrade-guide.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/upgrade-guide.md b/docs/upgrade-guide.md
index d57e5827214..78d95fe8031 100644
--- a/docs/upgrade-guide.md
+++ b/docs/upgrade-guide.md
@@ -34,7 +34,7 @@ Breaking changes:
 
 ### MapViewState / ViewportOptions
 
-- The `position` property changed from `number[]` to `[number, number, number]` (lat, lng, elevation).
+- The `position` property changed from `number[]` to `[number, number, number]` (lng, lat, elevation).
 
 ## Upgrading to v9.0