Struct Pj 

pub struct Pj { /* private fields */ }

A prepared coordinate operation with input/output unit handling.

Wraps an inner Operation and applies the unit conversions, prime-meridian and central-meridian shifts, and axis bookkeeping that PROJ performs around the raw projection math.

Field visibility and invariants

A Pj is a prepared operation: its fields are mutually consistent by construction (only crate::create and the crate-internal registry::build_single_op produce a valid one). All fields are therefore pub(crate) and reachable from outside the crate only through the read accessors on Pj. Flipping, for example, inverted or bypass_prepare_finalize after construction would silently invalidate the prepare/finalize contract, so those knobs are deliberately not externally writable.

The operation’s boundary — its reference ellipsoid and forward-sense input/output units — is exposed read-only through the ellipsoid, left and right accessors, which downstream crates (the CLI, parity harnesses) depend on. Their invariant: left/right are the forward-sense input/output units of the whole operation, and ellipsoid is the reference ellipsoid the boundary math is expressed against. They are read-only; mutating them would not re-derive any of the dependent fields.

Implementations

impl Pj

pub fn operation(&self) -> &dyn Operation

The inner operation (projection or conversion) as a trait reference.

pub fn op_name(&self) -> &str

The operation name (e.g. "merc", "axisswap"); empty for a pipeline.

pub fn inverted(&self) -> bool

Whether this operation runs inverted in its containing pipeline.

pub fn inner_has_inverse(&self) -> bool

Whether the wrapped inner operation provides an inverse.

Unlike the Operation::has_inverse default (which the Pj wrapper inherits as always-true), this reports the inner operation’s own answer — e.g. false for a forward-only projection like urm5 or a singular affine. The pipeline builder uses it to reject, at creation time, a step whose required direction has no implementation, mirroring PROJ’s pj_create_pipeline forward-path check (src/pipeline.cpp).

pub fn is_latlong(&self) -> bool

Whether this is a pass-through geographic (lat/long) operation.

pub fn lam0(&self) -> f64

Central meridian (radians).

pub fn phi0(&self) -> f64

Latitude of origin (radians).

pub fn x0(&self) -> f64

False easting (meters, pre-scale).

pub fn y0(&self) -> f64

False northing (meters, pre-scale).

pub fn z0(&self) -> f64

False up (meters, pre-scale).

pub fn k0(&self) -> f64

Scale factor at the central meridian.

pub fn to_meter(&self) -> f64

Horizontal input-unit-to-meter factor.

pub fn fr_meter(&self) -> f64

Horizontal meter-to-output-unit factor.

pub fn vto_meter(&self) -> f64

Vertical input-unit-to-meter factor.

pub fn vfr_meter(&self) -> f64

Vertical meter-to-output-unit factor.

pub fn from_greenwich(&self) -> f64

Prime-meridian offset from Greenwich (radians).

pub fn over(&self) -> bool

Allow longitudes outside the normal range (+over).

pub fn geoc(&self) -> bool

Geocentric latitude flag (+geoc).

pub fn ellipsoid(&self) -> Ellipsoid

The reference ellipsoid the boundary math is expressed against.

pub fn left(&self) -> IoUnits

Input units of the whole operation (forward direction).

pub fn right(&self) -> IoUnits

Output units of the whole operation (forward direction).

pub fn forward(&self, c: Coord) -> ProjResult<Coord>

Run the operation in the forward direction, honoring inverted.

pub fn inverse(&self, c: Coord) -> ProjResult<Coord>

Run the operation in the inverse direction, honoring inverted.

pub fn factors(&self, coord: Coord) -> ProjResult<Factors>

Compute map-scale factors (Tissot indicatrix) at a geographic coordinate.

coord must be in geographic input units — radians if self.left == IoUnits::Radians, degrees if self.left == IoUnits::Degrees. The coordinate layout is Coord::new(longitude, latitude, z, t).

Returns the oxiproj_core::Factors struct describing Tissot indicatrix parameters at the given point.

Ported from PROJ 9.8.0 src/factors.cpp (proj_factors → pj_factors → pj_deriv).

pub fn factors_exact(&self, coord: Coord) -> ProjResult<FactorsExact>

Compute exact distortion factors via automatic differentiation.

Returns Err(ProjError::UnsupportedOperation) when:

• ad_proj is None (no AD-capable projection registered), or
• the projection’s project_fwd_generic returns UnsupportedOperation.

coord must be in the same geographic input units as for Pj::factors.

Trait Implementations

impl Debug for Pj

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Operation for Pj

fn forward_4d(&self, c: Coord) -> ProjResult<Coord>

Apply the 4D forward operation on a full Coord (with time).

fn inverse_4d(&self, c: Coord) -> ProjResult<Coord>

Apply the 4D inverse operation on a full Coord (with time).

fn forward_2d(&self, lp: Lp) -> ProjResult<Xy>

Apply the 2D forward operation, mapping geodetic Lp to projected Xy.

fn inverse_2d(&self, xy: Xy) -> ProjResult<Lp>

Apply the 2D inverse operation, mapping projected Xy back to geodetic Lp.

fn forward_3d(&self, lpz: Lpz) -> Result<Xyz, ProjError>

Apply the 3D forward operation, mapping geodetic Lpz to Cartesian Xyz.

fn inverse_3d(&self, xyz: Xyz) -> Result<Lpz, ProjError>

Apply the 3D inverse operation, mapping Cartesian Xyz back to geodetic Lpz.

fn has_inverse(&self) -> bool

Report whether an inverse operation is available (default true).