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Projection

rustial_engine

Trait Projection 

Source 
pub trait Projection: Send + Sync {
    // Required methods
    fn project(&self, geo: &GeoCoord) -> WorldCoord;
    fn unproject(&self, world: &WorldCoord) -> GeoCoord;

    // Provided methods
    fn scale_factor(&self, _geo: &GeoCoord) -> f64 { ... }
    fn projection_bounds(&self) -> GeoBounds { ... }
}
Expand description

A map projection that converts between geographic and projected coordinates.

Implementations must be thread-safe (Send + Sync) so they can be shared across rendering and engine threads.

Required Methods§

Source

fn project(&self, geo: &GeoCoord) -> WorldCoord

Project a geographic coordinate to world space (meters).

Source

fn unproject(&self, world: &WorldCoord) -> GeoCoord

Inverse-project world coordinates back to geographic.

Provided Methods§

Source

fn scale_factor(&self, _geo: &GeoCoord) -> f64

Local linear scale factor at the given geographic coordinate.

Returns the ratio of projected distance to true geodesic distance at geo. For a conformal projection like Web Mercator this is 1 / cos(lat) (i.e. sec(lat)); for Equirectangular at the equator it is 1.0.

Useful for computing meters-per-pixel, line-width scaling, and LOD thresholds.

The default implementation returns 1.0 (no distortion), which is correct only at the standard parallel.

Source

fn projection_bounds(&self) -> GeoBounds

The geographic bounding box of valid input for this projection.

Coordinates outside this range may produce NaN or Infinity when projected. For example, Web Mercator is valid only within approximately 85.06 degrees latitude.

The default implementation returns the full geographic range (90 degrees lat, 180 degrees lon).

Implementors§