Struct Grid 

#[non_exhaustive]
pub struct Grid {
    pub ni: u32,
    pub nj: u32,
    pub earth: Earth,
    pub south_to_north: bool,
    pub winds_grid_relative: bool,
    pub projection: Projection,
}

A field’s grid: its size, its projection and how its points are ordered.

Points are numbered i + ni · j, i along a row (east on a latitude/longitude grid, +x on a Lambert grid) and j from row to row. Rows run south to north when Grid::south_to_north, else north to south; the reader refuses other scanning modes.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

ni: u32

Points along a row.

nj: u32

Rows.

earth: Earth

The figure of the Earth.

south_to_north: bool

Whether rows run south to north (+j, scanning mode bit 2); otherwise north to south.

winds_grid_relative: bool

Whether vector components (winds) are along the grid’s x and y axes rather than east and north (flag table 3.3, bit 5).

projection: Projection

The projection.

Implementations

impl Grid

pub fn points(&self) -> u64

The points, ni · nj.

pub fn point_deg(&self, index: u64) -> Option<(f64, f64)>

Grid point index’s latitude (degrees north) and longitude (degrees east, in [0, 360)), or None outside the grid.

pub fn circles_the_earth(&self) -> bool

Whether a latitude/longitude grid’s rows go all the way round the Earth: ni steps of di make 360°, so the point after the last in a row is the row’s first. A step is written in millionths of a degree, so a 1/12° grid’s 4,320 steps of 0.083333° make 359.9986°: the test allows a millionth of a degree a step, for an encoder that truncates.

pub fn index_at(&self, latitude_deg: f64, longitude_deg: f64) -> (f64, f64)

The fractional grid indices (i, j) of a place, such that grid point (⌊i⌋, ⌊j⌋) and its neighbours at +1 surround it; the place may be outside the grid.

pub fn north_to_grid_y_rad(&self, longitude_deg: f64) -> f64

The angle from true north to the grid’s +y axis at a place, clockwise positive, rad: θ = n (λ − λ₀) on a Lambert grid (Snyder eq. 14-4), 0 on a latitude/longitude grid, whose axes point east and north. West of the central meridian θ < 0: the meridians lean toward the cone’s apex, so north is turned toward +x and the grid’s +y west of north.

pub fn earth_relative_wind( &self, u_m_s: f64, v_m_s: f64, longitude_deg: f64, ) -> (f64, f64)

A wind’s east and north components, m/s, from its components as the field gives them: unchanged unless Grid::winds_grid_relative, else turned from the grid’s axes.

On a Lambert grid true north is (−sin θ, cos θ) in grid axes and east (cos θ, sin θ), with θ = n (λ − λ₀), so u_east = u cos θ + v sin θ and v_north = −u sin θ + v cos θ.

Trait Implementations

impl Clone for Grid

fn clone(&self) -> Grid

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Grid

impl Debug for Grid

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Grid

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Grid

fn eq(&self, other: &Grid) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Grid

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Grid