Support MultiPoint

Author: platypii

README.md

@@ -6,7 +6,8 @@
 [![minzipped](https://img.shields.io/bundlephobia/minzip/geoparquet)](https://www.npmjs.com/package/geoparquet)
 [![workflow status](https://github.com/hyparam/geoparquet/actions/workflows/ci.yml/badge.svg)](https://github.com/hyparam/geoparquet/actions)
 [![mit license](https://img.shields.io/badge/License-MIT-orange.svg)](https://opensource.org/licenses/MIT)
-![coverage](https://img.shields.io/badge/Coverage-97-darkred)
+![coverage](https://img.shields.io/badge/Coverage-94-darkred)
+[![dependencies](https://img.shields.io/badge/Dependencies-1-blueviolet)](https://www.npmjs.com/package/geoparquet?activeTab=dependencies)
 
 **GeoParquet** provides a pure JavaScript workflow to read and convert [GeoParquet](https://github.com/opengeospatial/geoparquet) files into [GeoJSON](https://datatracker.ietf.org/doc/html/rfc7946). Under the hood, it uses the [hyparquet](https://github.com/hyparam/hyparquet) library for efficient in-browser parquet parsing, enabling minimal overhead and fast loading.
 

src/wkb.js

@@ -103,7 +103,20 @@ export function decodeWKB(wkb) {
     return { type: 'MultiPolygon', coordinates: polygons }
   } else if (geometryType === geometryTypeMultiPoint) {
     // MultiPoint
-    throw new Error('Unsupported geometry type: MultiPoint')
+    const numPoints = dv.getUint32(offset, isLittleEndian); offset += 4
+    const points = []
+    for (let i = 0; i < numPoints; i++) {
+      // Each point has its own byte order & geometry type
+      const pointIsLittleEndian = wkb[offset] === 1; offset += 1
+      const pointType = dv.getUint32(offset, pointIsLittleEndian); offset += 4
+      if (pointType !== geometryTypePoint) {
+        throw new Error(`Expected Point in MultiPoint, got ${pointType}`)
+      }
+      const x = dv.getFloat64(offset, pointIsLittleEndian); offset += 8
+      const y = dv.getFloat64(offset, pointIsLittleEndian); offset += 8
+      points.push([x, y])
+    }
+    return { type: 'MultiPoint', coordinates: points }
   } else if (geometryType === geometryTypeMultiLineString) {
     // MultiLineString
     const numLineStrings = dv.getUint32(offset, isLittleEndian); offset += 4

test/files/data-multipoint-encoding_wkb.json

@@ -0,0 +1,42 @@
+{
+  "features": [
+    {
+      "geometry": {
+        "coordinates": [
+          [ 30, 10 ]
+        ],
+        "type": "MultiPoint"
+      },
+      "properties": {
+        "col": 0
+      },
+      "type": "Feature"
+    },
+    {
+      "geometry": {
+        "coordinates": [
+          [ 10, 40 ],
+          [ 40, 30 ],
+          [ 20, 20 ],
+          [ 30, 10 ]
+        ],
+        "type": "MultiPoint"
+      },
+      "properties": {
+        "col": 1
+      },
+      "type": "Feature"
+    },
+    {
+      "geometry": {
+        "coordinates": [],
+        "type": "MultiPoint"
+      },
+      "properties": {
+        "col": 2
+      },
+      "type": "Feature"
+    }
+  ],
+  "type": "FeatureCollection"
+}