> ## Documentation Index
> Fetch the complete documentation index at: https://algolia.com/llms.txt
> Use this file to discover all available pages before exploring further.

# How to solve the 180th meridian issue

> To solve the 180th meridian issue, create two separate areas east and west of this line

The [180th meridian](https://wikipedia.org/wiki/180th_meridian) is the geographical boundary between the Eastern and Western hemispheres.
It passes through the Pacific Ocean, Russia, Alaska, and Fiji.

## 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.

## 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.

## 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.

### 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`](/doc/api-reference/api-parameters/insideBoundingBox) to define these shapes with the value `[[70, 170, 60, 180], [70, -180, 60, -170]]`.

### 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`](/doc/api-reference/api-parameters/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)