Bounding Boxes

Working with Bounding Boxes

bboxFromGeoJSON

Calculates or extracts bounding boxes from GeoJSON objects. The function intelligently handles various GeoJSON types and optimizes performance:

Uses existing bbox properties when available (fastest)
Calculates from geometry coordinates when needed
Aggregates bounding boxes from collections
Optimizes large geometries by sampling points

Key behavior: The function prioritizes existing bbox fields over geometry calculations, which is important for Point features from TomTom services that may have a bbox representing a broader area than just the point location.

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import { bboxFromGeoJSON } from '@tomtom-org/maps-sdk/core';
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// From a Place with existing bbox
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const place = await geocode({ key: 'your-api-key', query: 'Amsterdam' });
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const bbox1 = bboxFromGeoJSON(place);
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// Returns the bbox that came with the place
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// From a Polygon geometry (calculates bbox)
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const polygon = {
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  type: 'Polygon',
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  coordinates: [[
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    [4.88, 52.36],
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    [4.90, 52.36],
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    [4.90, 52.38],
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    [4.88, 52.38],
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    [4.88, 52.36]
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  ]]
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};
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const bbox2 = bboxFromGeoJSON(polygon);
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// Returns: [4.88, 52.36, 4.90, 52.38]
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// From a FeatureCollection (aggregates all features)
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const places = await search({ key: 'your-api-key', query: 'coffee' });
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const bbox3 = bboxFromGeoJSON(places);
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// Returns bbox encompassing all search results
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// From a LineString (calculates from coordinates)
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const route = await calculateRoute({
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  key: 'your-api-key',
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  locations: [[4.9, 52.3], [4.5, 51.9]]
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});
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const bbox4 = bboxFromGeoJSON(route.features[0].geometry);
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// Returns bbox containing the entire route
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// From an array of GeoJSON objects
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const bbox5 = bboxFromGeoJSON([place1, place2, place3]);
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// Returns bbox encompassing all three places

Returns: [minLng, minLat, maxLng, maxLat] | undefined – The bounding box, or undefined if input is invalid.

polygonFromBBox

Converts a bounding box into a GeoJSON Polygon Feature, useful for visualizing bounding box areas on a map.

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import { polygonFromBBox } from '@tomtom-org/maps-sdk/core';
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// Create a polygon from a bbox
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const bbox = [4.88, 52.36, 4.90, 52.38];
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const polygon = polygonFromBBox(bbox);
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// Returns a GeoJSON Feature with Polygon geometry
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// Visualize a bbox on a map
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const places = await search({ key: 'your-api-key', query: 'coffee' });
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const bbox = bboxFromGeoJSON(places);
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if (bbox) {
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  const bboxPolygon = polygonFromBBox(bbox);
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  map.addSource('bbox-area', {
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    type: 'geojson',
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    data: bboxPolygon
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  });
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  map.addLayer({
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    id: 'bbox-outline',
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    type: 'line',
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    source: 'bbox-area',
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    paint: { 'line-color': '#3887be', 'line-width': 2 }
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  });
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}

Parameters:

bbox – Bounding box as [west, south, east, north]

Returns: Feature<Polygon> – A GeoJSON Feature with a closed Polygon geometry representing the bbox area.