Trait DefaultArea 

pub trait DefaultArea<Family> {
    type Strategy: Default;
}

“Which (polygon) area strategy do we pick by default for this CS family?”

Mirrors v1’s DefaultDistance and DefaultLength — the Rust analogue of Boost’s services::default_strategy<Geometry, cs_tag> in strategies/area/services.hpp, specialised per CS in strategies/area/{cartesian,spherical,geographic}.hpp.

Keyed on the polygon area strategy, since the area(&polygon) free function is the entry point that dispatches through it:

impl DefaultArea<CartesianFamily>  for CartesianFamily  { type Strategy = ShoelacePolygonArea;   }
impl DefaultArea<SphericalFamily>  for SphericalFamily  { type Strategy = SphericalPolygonArea;  }
impl DefaultArea<GeographicFamily> for GeographicFamily { type Strategy = GeographicPolygonArea; }

Required Associated Types

type Strategy: Default

The area strategy chosen for this family. Must implement Default because the free-function area(g) builds it without arguments.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl DefaultArea<CartesianFamily> for CartesianFamily

Cartesian family defaults to ShoelacePolygonArea.

type Strategy = ShoelacePolygonArea

impl DefaultArea<GeographicFamily> for GeographicFamily

Geographic family defaults to GeographicPolygonArea — the authalic-sphere approximation (see its docs for the precision caveat).

type Strategy = GeographicPolygonArea

impl DefaultArea<SphericalFamily> for SphericalFamily

Spherical family defaults to SphericalPolygonArea.

type Strategy = SphericalPolygonArea

Implementors