Geometry utilities help you work with spatial data and features. 3DMapFi supports GeoJSON and provides helpers for geometry manipulation, measurement, and conversion.

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Supported Geometry Types

  • Point
  • LineString
  • Polygon
  • MultiPoint
  • MultiLineString
  • MultiPolygon
  • GeometryCollection

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Usage

// Example: Creating a GeoJSON point
const point = {
  type: "Feature",
  geometry: {
    type: "Point",
    coordinates: [105.85, 21.03]
  },
  properties: {}
};

// Add as a source
map.addSource('point', { type: 'geojson', data: point });

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Creating Other Geometries

// LineString
const line = {
  type: "Feature",
  geometry: {
    type: "LineString",
    coordinates: [[105.85, 21.03], [105.9, 21.05]]
  },
  properties: {}
};

// Polygon
const polygon = {
  type: "Feature",
  geometry: {
    type: "Polygon",
    coordinates: [[[105.8, 21.0], [105.9, 21.0], [105.9, 21.1], [105.8, 21.1], [105.8, 21.0]]]
  },
  properties: {}
};

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Geometry Utilities

  • Coordinate conversion: Convert between coordinate systems or projections.
  • Distance calculation: Measure distance between points.
  • Area calculation: Compute the area of polygons.
  • Centroid calculation: Find the center of a geometry.
  • Buffering: Create buffer zones around features.
  • Feature manipulation: Merge, split, or simplify geometries.

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Example: Calculating Distance

import { distance } from '@3dmapfi/mapfi/geometry';

const d = distance([105.85, 21.03], [105.9, 21.05]); // Returns distance in meters

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Example: Calculating Area

import { area } from '@3dmapfi/mapfi/geometry';

const a = area(polygon.geometry); // Returns area in square meters

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Example: Buffering a Point

import { buffer } from '@3dmapfi/mapfi/geometry';

const buffered = buffer(point.geometry, 100); // 100 meters buffer

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Working with Feature Collections

const featureCollection = {
  type: "FeatureCollection",
  features: [point, line, polygon]
};
map.addSource('features', { type: 'geojson', data: featureCollection });

See also: Map API