Struct Transform 

pub struct Transform { /* private fields */ }

A reusable coordinate transformation between two CRS.

Create once with Transform::new, then call convert or convert_3d for each coordinate. All input/output coordinates use the CRS’s native units: degrees (lon/lat) for geographic CRS, meters for projected CRS. For 3D coordinates, the third ordinate is preserved unchanged by the current horizontal-only pipeline.

Example

use proj_core::Transform;

let t = Transform::new("EPSG:4326", "EPSG:3857").unwrap();
let (x, y) = t.convert((-74.006, 40.7128)).unwrap();
assert!((x - (-8238310.0)).abs() < 1.0);

Implementations

impl Transform

pub fn new(from_crs: &str, to_crs: &str) -> Result<Self>

Create a transform from authority code strings (e.g., "EPSG:4326").

This is the primary constructor, matching the API pattern from C PROJ’s Proj::new_known_crs().

pub fn from_epsg(from: u32, to: u32) -> Result<Self>

Create a transform from EPSG codes directly.

pub fn from_crs_defs(from: &CrsDef, to: &CrsDef) -> Result<Self>

Create a transform from explicit CRS definitions.

Use this for custom CRS not in the built-in registry.

pub fn convert<T: Transformable>(&self, coord: T) -> Result<T>

Transform a single coordinate.

Input and output units are the native units of the respective CRS: degrees for geographic CRS, meters for projected CRS.

The return type matches the input type:

• (f64, f64) in → (f64, f64) out
• Coord in → Coord out
• geo_types::Coord<f64> in → geo_types::Coord<f64> out (with geo-types feature)

pub fn convert_3d<T: Transformable3D>(&self, coord: T) -> Result<T>

Transform a single 3D coordinate.

The horizontal components use the CRS’s native units: degrees for geographic CRS and meters for projected CRS. The vertical component is carried through unchanged because the current CRS model is horizontal-only.

The return type matches the input type:

• (f64, f64, f64) in → (f64, f64, f64) out
• Coord3D in → Coord3D out

pub fn source_crs(&self) -> &CrsDef

Return the source CRS definition for this transform.

pub fn target_crs(&self) -> &CrsDef

Return the target CRS definition for this transform.

pub fn inverse(&self) -> Result<Self>

Build the inverse transform by swapping the source and target CRS.

pub fn transform_bounds( &self, bounds: Bounds, densify_points: usize, ) -> Result<Bounds>

Reproject a 2D bounding box by sampling its perimeter.

densify_points controls how many evenly spaced interior points are sampled on each edge between the corners. 0 samples only the four corners.

The returned bounds are axis-aligned in the target CRS. Geographic outputs that cross the antimeridian are not normalized into a wrapped representation.

pub fn convert_batch<T: Transformable + Clone>( &self, coords: &[T], ) -> Result<Vec<T>>

Batch transform (sequential).

pub fn convert_batch_3d<T: Transformable3D + Clone>( &self, coords: &[T], ) -> Result<Vec<T>>

Batch transform of 3D coordinates (sequential).

pub fn convert_batch_parallel<T: Transformable + Send + Sync + Clone>( &self, coords: &[T], ) -> Result<Vec<T>>

Batch transform with Rayon parallelism.

pub fn convert_batch_parallel_3d<T: Transformable3D + Send + Sync + Clone>( &self, coords: &[T], ) -> Result<Vec<T>>

Batch transform of 3D coordinates with Rayon parallelism.