GeoPolygon

This class represents a polygon on the surface of the earth. It cannot be persisted - i.e you can't declare a Realm property that is of type GeoPolygon. It can be only used as a query argument for a geospatial query.

A GeoPolygon describes a shape represented by 3 or more line segments. It comprises of one outer ring and 0 or more rings representing holes with the following restrictions:

• Each ring must consist of at least 3 line segments. The first and the last point must be the same to indicate a closed ring (meaning you need at least 4 points to define the polygon).

• Rings may not cross, i.e. the boundary of a ring may not intersect both the interior and exterior of any other ring.

• Rings may not share edges, i.e. if a ring contains an edge AB, then no other ring may contain AB or BA.

• Rings may share vertices, however no vertex may appear twice in a single ring.

• No ring may be empty.

Holes may be nested inside each other, in which case a location will be considered "inside" the polygon if it is included in an odd number of rings, counting the outer ring as 1. For example, a polygon representing a square with side 10 centered at (0,0) with holes representing squares with sides 5 and 2, centered at (0,0) will include the location (1, 1) because it is contained in 3 rings, but not (3, 3), because it is contained in 2.

Using it can look something like this:

val searchArea = GeoPolygon.create(
    outerRing = listOf(
        GeoPoint.create(0.0, 0.0),
        GeoPoint.create(0.0, 5.0),
        GeoPoint.create(5.0, 5.0),
        GeoPoint.create(5.0, 0.0),
        GeoPoint.create(0.0, 0.0),
    ),
    holes = arrayOf(listOf(
        GeoPoint.create(1.0, 1.0),
        GeoPoint.create(1.0, 4.0),
        GeoPoint.create(4.0, 4.0),
        GeoPoint.create(4.0, 1.0)
    ))
)
val restaurants = realm.query<Restaurant>("location GEOWITHIN $0", searchArea).find()