feat: add GeoTIFF coordinate transformation node (#184)

Add GeoTiffTransformNode to transform GeoTIFF metadata from WGS84
(EPSG:4326) to Web Mercator (EPSG:3857) projection.

- Validates CRS is EPSG:4326 before transformation
- Transforms bounds array from [west, south, east, north] degrees to [minX, minY, maxX, maxY] meters
- Sets output CRS to EPSG:3857

Author: rmarquis

apps/api/src/nodes/3d/geotiff-transform-node.ts

@@ -0,0 +1,98 @@
+import { NodeExecution, NodeType } from "@dafthunk/types";
+
+import { ExecutableNode, NodeContext } from "../types";
+
+// Import projection utilities from 3dtiles package
+// These will need to be available in the API context
+// You may need to adjust the import path based on your workspace setup
+
+export class GeoTiffTransformNode extends ExecutableNode {
+  public static readonly nodeType: NodeType = {
+    id: "geotiff-transform",
+    name: "GeoTIFF Transform to Web Mercator",
+    type: "geotiff-transform",
+    description:
+      "Transform GeoTIFF metadata from WGS84 (EPSG:4326) to Web Mercator (EPSG:3857)",
+    tags: ["3D", "Geo"],
+    icon: "map",
+    inputs: [
+      {
+        name: "metadata",
+        type: "json",
+        description: "GeoTIFF metadata from GeoTIFF Metadata Reader",
+        required: true,
+      },
+    ],
+    outputs: [
+      {
+        name: "transformed",
+        type: "json",
+        description: "Metadata with Web Mercator bounds",
+      },
+    ],
+  };
+
+  public async execute(context: NodeContext): Promise<NodeExecution> {
+    try {
+      const { metadata } = context.inputs;
+
+      // Validate CRS is EPSG:4326 before transformation
+      if (metadata.crs && metadata.crs !== "EPSG:4326") {
+        return this.createErrorResult(
+          `Cannot transform: expected EPSG:4326, but metadata has CRS: ${metadata.crs}`
+        );
+      }
+
+      // Extract bounds from metadata
+      const [west, south, east, north] = metadata.bounds;
+
+      // Transform WGS84 bounds to Web Mercator
+      const [minX, minY] = this.WGS84toEPSG3857(west, south);
+      const [maxX, maxY] = this.WGS84toEPSG3857(east, north);
+
+      // Create transformed metadata with Web Mercator bounds
+      const transformed = {
+        ...metadata,
+        bounds: [minX, minY, maxX, maxY],
+        crs: "EPSG:3857",
+      };
+
+      return this.createSuccessResult({ transformed });
+    } catch (error) {
+      const errorMessage =
+        error instanceof Error ? error.message : "Unknown error";
+      return this.createErrorResult(
+        `Failed to transform GeoTIFF metadata: ${errorMessage}`
+      );
+    }
+  }
+
+  /**
+   * Convert WGS84 geographic coordinates to Web Mercator coordinates
+   *
+   * Based on proj4 EPSG:3857 transformation.
+   * Web Mercator is widely used by web mapping services.
+   *
+   * @param lon - WGS84 longitude in degrees (-180 to +180)
+   * @param lat - WGS84 latitude in degrees (-85.0511 to +85.0511)
+   * @returns Web Mercator coordinates [x, y] in meters
+   */
+  private WGS84toEPSG3857(lon: number, lat: number): [number, number] {
+    // Web Mercator constants
+    const EARTH_RADIUS = 6378137; // WGS84 semi-major axis in meters
+    const MAX_LATITUDE = 85.0511287798; // Max latitude for Web Mercator
+
+    // Clamp latitude to valid Web Mercator range
+    const clampedLat = Math.max(-MAX_LATITUDE, Math.min(MAX_LATITUDE, lat));
+
+    // Convert to radians
+    const lonRad = (lon * Math.PI) / 180;
+    const latRad = (clampedLat * Math.PI) / 180;
+
+    // Web Mercator formulas
+    const x = EARTH_RADIUS * lonRad;
+    const y = EARTH_RADIUS * Math.log(Math.tan(Math.PI / 4 + latRad / 2));
+
+    return [x, y];
+  }
+}

apps/api/src/nodes/cloudflare-node-registry.ts

@@ -3,6 +3,7 @@ import { DemToBufferGeometryNode } from "./3d/dem-to-buffergeometry-node";
 import { GeoTiffDemQueryNode } from "./3d/geotiff-dem-query-node";
 import { GeoTiffMetadataReaderNode } from "./3d/geotiff-metadata-reader-node";
 import { GeoTiffQueryNode } from "./3d/geotiff-query-node";
+import { GeoTiffTransformNode } from "./3d/geotiff-transform-node";
 import { Claude3OpusNode } from "./anthropic/claude-3-opus-node";
 import { Claude35HaikuNode } from "./anthropic/claude-35-haiku-node";
 import { Claude35SonnetNode } from "./anthropic/claude-35-sonnet-node";
@@ -480,6 +481,7 @@ export class CloudflareNodeRegistry extends BaseNodeRegistry {
       this.registerImplementation(GeoTiffDemQueryNode);
       this.registerImplementation(GeoTiffMetadataReaderNode);
       this.registerImplementation(GeoTiffQueryNode);
+      this.registerImplementation(GeoTiffTransformNode);
     }
 
     // Geo nodes