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Geometries at the Antimeridian

OneStop does not support geometries that cross both the antimeridian and prime meridian, particularly bounding boxes, if those polygons are represented in GeoJSON with numerically discontinuous longitudes. For smaller geometries which cross the antimeridian, OneStop does support them, but other related services may not.

Special care must be taken for geometries that cross the antimeridian. This is true for both loading data into the system, as well as for spatial queries.

There are several possible solutions, but it is the responsibility of the data provider to provide geometries correctly.

Note: in the case of providing data via EX_GeographicBoundingBox in ISO records, no changes need to be made. OneStop uses GeoJSON MultiPolygon automatically for bounding boxes that cross the antimeridian.

Examples
References

Examples

Consider this bounding box used in a query:

Bounding box covering the majority of the North Pacific Ocean, North America, and the North Atlantic Ocean

Or a granule with this polygon showing the arc of data from a polar satellite:

Trapezoid through the East Siberian Sea and northern Alaska

Misinterpretations

It may be tempting to write this bounding box with the polygon:

{
  "type": "Polygon",
  "coordinates": [
    [
      [150, 0],
      [10, 0],
      [10, 70],
      [150, 70],
      [150, 0]
    ]
  ]
}

and the polygon with:

{
  "coordinates": [
    [
      [89.03714, 83.41194],
      [110.17727, 79.45783],
      [-152.8746, 65.788704],
      [-140.4437, 67.28255],
      [89.03714, 83.41194]
    ]
  ],
  "type": "Polygon"
}

However, due to the numerical discontinuity at ±180, the bounding box will be interpreted by OneStop as:

Bounding box covering Eastern Europe and the majority of Russia

And some tools and services may treat the polygon as though it is this one instead:

Triangle-shaped trapezoid from the East Siberian Sea that ends in Alaska by going through Greenland and Canada

Correction with MultiPolygons (recommended)

The preferred way to write GeoJSON geometries to prevent these errors is by splitting into a MultiPolygon. This is to support interoperability between systems that require longitudes be restricted to values in the range ±180.

Bounding box broken into two shapes: the first covering the North Pacific Ocean starting at the antimeridian, including Alaska, and the majority of North America, and the North Atlantic Ocean, and the second that covers the portion of the North Pacific Ocean including parts of Russia.

Here is the GeoJSON for the Bounding Box in MultiPolygon form:

{
  "type": "MultiPolygon",
  "coordinates": [
    [
      [
        [150, 0],
        [180, 0],
        [180, 70],
        [150, 70],
        [150, 0]
      ]
    ],
    [
      [
        [-180, 0],
        [10, 0],
        [10, 70],
        [-180, 70],
        [-180, 0]
      ]
    ]
  ]
}

Trapezoid broken into two shapes: the first through the East Siberian Sea at the right edge of the map, and the second that crosses into Alaska on the left side of the map.

Here is the GeoJSON for the Polygon in MultiPolygon form:

{
  "type": "MultiPolygon",
  "coordinates": [
    [
      [
        [-180, 69.61322862],
        [-152.8746, 65.788704],
        [-140.4437, 67.28255],
        [-180, 72.1708667],
        [-180, 69.61322862]
      ]
    ],
    [
      [
        [180, 72.1708667],
        [89.03714, 83.41194],
        [110.17727, 79.45783],
        [180, 69.61322862],
        [180, 72.1708667]
      ]
    ]
  ]
}

Correction with Shifted Longitudes

Another solution is to shift some of the coordinates, so that they have the correct relative values on a number line.

Although OneStop searching will work correctly with all of the following GeoJSON, loading data with these may cause errors for other tools and services that rely on OneStop.

Bounding Box:

{
  "type": "Polygon",
  "coordinates": [
    [
      [-210, 0],
      [10, 0],
      [10, 70],
      [-210, 70],
      [-210, 0]
    ]
  ]
}

{
  "type": "Polygon",
  "coordinates": [
    [
      [150, 0],
      [370, 0],
      [370, 70],
      [150, 70],
      [150, 0]
    ]

  ]
}

Polygon:

{
  "coordinates": [
    [
      [89.03714, 83.41194],
      [110.17727, 79.45783],
      [207.1254, 65.788704],
      [219.5563, 67.28255],
      [89.03714, 83.41194]
    ]
  ],
  "type": "Polygon"
}

{
  "coordinates": [
    [
      [-270.96286, 83.41194],
      [-249.82273, 79.45783],
      [-152.8746, 65.788704],
      [-140.4437, 67.28255],
      [-270.96286, 83.41194]
    ]
  ],
  "type": "Polygon"
}

References

GeoJSON Format GeoJSON Lint

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