The 180th meridian is the geographical boundary between the Eastern and Western hemispheres. It passes through the Pacific Ocean, Russia, Alaska, and Fiji.

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The problem

When searching by location, the 180th meridian can lead to unexpected results. If a rectangle or polygon includes the 180th meridian, the search won’t include results from inside the area. Instead, the results return everything outside the area you selected.

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The reason: longitudinal value reversal

When you cross the 180th meridian, the longitude switches from positive to negative numbers: from 180 to -180, not 181.

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The solution: create two areas

If your area crosses the meridian, split the affected area into two adjacent shapes, one east of the meridian and one west.

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Rectangles

Consider a rectangle that includes the 180th meridian: [70, 170, 60, -170]. To resolve the issue, split this rectangle into two smaller ones:
  • Rectangle 1: [70, 170, 60, 180] (east of the meridian)
  • Rectangle 2: [70, -180, 60, -170] (west of the meridian)
Use insideBoundingBox to define these shapes with the value [[70, 170, 60, 180], [70, -180, 60, -170]].

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Polygons

Consider a polygon that includes the 180th meridian: [[70, 170], [80, 160], [90, 140], [80, 120], [70, 110], [60, 130], [70, 140]]. To resolve the issue, use insidePolygon to split this shape into two smaller ones:
  • Polygon 1: [[70, 170], [80, 160], [90, 140], [80, 120], [70, 110], [60, 130], [70, 140]] (area east of the meridian)
  • Polygon 2: [[60, 130], [70, 140], [70, 170], [60, 180], [50, 160], [60, 150], [60, 130]] (area west of the meridian)