A CoordTrait experiment (#103)

Essentially:

- Traitify coordinate access
- Add dim() as required impl for `CoordinateSet`

In detail:

- A CoordTrait experiment
- Simplified, and added dimension+measure
- Trait impl of ISO-19111 coordinate tuple
- Angular conversions in CoordinateTuple
- Extend and use CoordinateTuple trait. dim in CoordinateSet
- Prefix unchecked to postfix
- xy/set_xy for CoordinateSet. Tests via tmerc/merc

Author: busstoptaktik

Cargo.toml

@@ -18,6 +18,7 @@ default-run = "kp"
 [dependencies]
 # Library functionality
 uuid = { version = "1", features = ["v4"] }
+num-traits = { version = "0.2" }
 
 # Command line program helpers
 clap = { version = "4.3.11", features = ["derive"], optional = true }

examples/00-transformations.rs

@@ -37,8 +37,7 @@ fn main() -> anyhow::Result<()> {
     // But since a coordinate tuple is really just an array of double
     // precision numbers, you may also generate it directly using plain
     // Rust syntax. Note that Coor2D, like f64, provides the to_radians
-    // method. So compared to cph_raw above, we can use a slightly more
-    // compact notation.
+    // method, but it operates in place, so we need two steps in this case.
     let cph_direct = Coor2D([12., 55.]).to_radians();
     // The three versions of Copenhagen coordinates should be identical.
     assert_eq!(cph, cph_raw);
@@ -79,8 +78,8 @@ fn main() -> anyhow::Result<()> {
     // Note the use of `to_geo`, which transforms lon/lat in radians
     // to lat/lon in degrees. It is defined for Coor2D as well as for
     // arrays, vectors and slices of Coor2D
-    for coord in data.to_geo() {
-        println!("    {:?}", coord);
+    for coord in data {
+        println!("    {:?}", coord.to_geo());
     }
 
     // To geo again, but using slices - in two different ways

examples/01-geometric_geodesy.rs

@@ -46,8 +46,8 @@ fn main() -> Result<(), Error> {
     // surface of the ellipsoid. Let's compute the distance and
     // azimuth between the approximate locations of the airports
     // of Copenhagen (CPH) and Paris (CDG).
-    let CPH = Coor4D::geo(55., 12., 0., 0.);
-    let CDG = Coor4D::geo(49., 2., 0., 0.);
+    let CPH = Coor2D::geo(55., 12.);
+    let CDG = Coor2D::geo(49., 2.);
 
     // By historical convention the "from A to B" situation is considered
     // the inverse sense of the geodesic problem - hence `geodesic_inv`:

examples/02-user_defined_macros.rs

@@ -46,10 +46,9 @@ fn main() -> anyhow::Result<()> {
 
     // data.to_geo() transforms all elements in data from the internal GIS
     // format (lon/lat in radians) to lat/lon in degrees.
-    data.to_geo();
     println!("Back to ed50:");
     for coord in data {
-        println!("    {:?}", coord);
+        println!("    {:?}", coord.to_geo());
     }
 
     Ok(())

examples/06-user_defined_coordinate_types_and_containers.rs

@@ -75,6 +75,9 @@ impl CoordinateSet for AbscissaCollection {
     fn len(&self) -> usize {
         4
     }
+    fn dim(&self) -> usize {
+        1
+    }
 }
 
 fn main() -> Result<(), anyhow::Error> {

examples/07-examples_from_ruminations.rs

@@ -61,9 +61,8 @@ fn rumination_000() -> Result<(), anyhow::Error> {
 
     // [6] And go back, i.e. utm -> geo
     ctx.apply(utm32, Inv, &mut data)?;
-    data.to_geo();
     for coord in data {
-        println!("{:?}", coord);
+        println!("{:?}", coord.to_geo());
     }
 
     Ok(())

examples/08-user_defined_operators_using_proj.rs

@@ -173,6 +173,7 @@ pub fn proj_constructor(parameters: &RawParameters, _ctx: &dyn Context) -> Resul
 fn main() -> anyhow::Result<()> {
     let mut prv = geodesy::Minimal::new();
     prv.register_op("proj", OpConstructor(proj_constructor));
+    let e = Ellipsoid::default();
 
     // Check that we can access the `proj` binary - if not, just ignore
     if Command::new("proj").stderr(Stdio::piped()).spawn().is_err() {
@@ -195,7 +196,7 @@ fn main() -> anyhow::Result<()> {
     println!("projected: {:?}", geo[0]);
 
     ctx.apply(op, Inv, &mut geo)?;
-    assert!(rtp[0].default_ellps_dist(&geo[0]) < 1e-5);
+    assert!(e.distance(&rtp[0], &geo[0]) < 1e-5);
     println!("roundtrip: {:?}", geo[0].to_degrees());
 
     // Inverted invocation - note "proj inv ..."
@@ -208,7 +209,7 @@ fn main() -> anyhow::Result<()> {
 
     // Now, we get the inverse utm projection when calling the operator in the Fwd direction
     ctx.apply(op, Fwd, &mut utm)?;
-    assert!(geo[0].default_ellps_dist(&utm[0]) < 1e-5);
+    assert!(e.distance(&utm[0], &geo[0]) < 1e-5);
     // ...and roundtrip back to utm
     ctx.apply(op, Inv, &mut utm)?;
     assert!(rtp[0].hypot2(&utm[0]) < 1e-5);

src/context/minimal.rs

@@ -143,16 +143,16 @@ mod tests {
         assert_eq!(steps[2], "addone inv");
 
         let mut data = some_basic_coor2dinates();
-        assert_eq!(data[0][0], 55.);
-        assert_eq!(data[1][0], 59.);
+        assert_eq!(data[0].x(), 55.);
+        assert_eq!(data[1].x(), 59.);
 
         assert_eq!(2, ctx.apply(op, Fwd, &mut data)?);
-        assert_eq!(data[0][0], 56.);
-        assert_eq!(data[1][0], 60.);
+        assert_eq!(data[0].x(), 56.);
+        assert_eq!(data[1].x(), 60.);
 
         ctx.apply(op, Inv, &mut data)?;
-        assert_eq!(data[0][0], 55.);
-        assert_eq!(data[1][0], 59.);
+        assert_eq!(data[0].x(), 55.);
+        assert_eq!(data[1].x(), 59.);
 
         let params = ctx.params(op, 1)?;
         let ellps = params.ellps(0);
@@ -168,8 +168,8 @@ mod tests {
         let op = ctx.op("geo:in | utm zone=32 | neu:out")?;
 
         let mut data = some_basic_coor2dinates();
-        assert_eq!(data[0][0], 55.);
-        assert_eq!(data[1][0], 59.);
+        assert_eq!(data[0].x(), 55.);
+        assert_eq!(data[1].x(), 59.);
 
         ctx.apply(op, Fwd, &mut data)?;
         let expected = [6098907.825005002, 691875.6321396609];

src/context/plain.rs

@@ -312,16 +312,16 @@ mod tests {
 
         // ...and it works as expected?
         let mut data = some_basic_coor2dinates();
-        assert_eq!(data[0][0], 55.);
-        assert_eq!(data[1][0], 59.);
+        assert_eq!(data[0].x(), 55.);
+        assert_eq!(data[1].x(), 59.);
 
         ctx.apply(op, Fwd, &mut data)?;
-        assert_eq!(data[0][0], 56.);
-        assert_eq!(data[1][0], 60.);
+        assert_eq!(data[0].x(), 56.);
+        assert_eq!(data[1].x(), 60.);
 
         ctx.apply(op, Inv, &mut data)?;
-        assert_eq!(data[0][0], 55.);
-        assert_eq!(data[1][0], 59.);
+        assert_eq!(data[0].x(), 55.);
+        assert_eq!(data[1].x(), 59.);
 
         // Now test that the look-up functionality works in general
 
@@ -344,8 +344,8 @@ mod tests {
         let mut data = some_basic_coor2dinates();
 
         ctx.apply(op, Fwd, &mut data)?;
-        assert_eq!(data[0][0], 57.);
-        assert_eq!(data[1][0], 61.);
+        assert_eq!(data[0].x(), 57.);
+        assert_eq!(data[1].x(), 61.);
 
         // 3 Console tests from stupid.md
         let op = ctx.op("stupid:bad");
@@ -354,14 +354,14 @@ mod tests {
         let op = ctx.op("stupid:addthree")?;
         let mut data = some_basic_coor2dinates();
         ctx.apply(op, Fwd, &mut data)?;
-        assert_eq!(data[0][0], 58.);
-        assert_eq!(data[1][0], 62.);
+        assert_eq!(data[0].x(), 58.);
+        assert_eq!(data[1].x(), 62.);
 
         let op = ctx.op("stupid:addthree_one_by_one")?;
         let mut data = some_basic_coor2dinates();
         ctx.apply(op, Fwd, &mut data)?;
-        assert_eq!(data[0][0], 58.);
-        assert_eq!(data[1][0], 62.);
+        assert_eq!(data[0].x(), 58.);
+        assert_eq!(data[1].x(), 62.);
 
         // Make sure we can access "sigil-less runtime defined resources"
         ctx.register_resource("foo", "bar");

src/coordinate/coor2d.rs

@@ -1,12 +1,11 @@
 use super::*;
 use crate::math::angular;
-use std::ops::{Index, IndexMut};
 
 /// Generic 2D Coordinate tuple, with no fixed interpretation of the elements
 #[derive(Debug, Default, PartialEq, Copy, Clone)]
 pub struct Coor2D(pub [f64; 2]);
 
-// ----- O P E R A T O R   T R A I T S -------------------------------------------------
+use std::ops::{Index, IndexMut};
 
 impl Index<usize> for Coor2D {
     type Output = f64;
@@ -21,34 +20,6 @@ impl IndexMut<usize> for Coor2D {
     }
 }
 
-// ----- A N G U L A R   U N I T S -------------------------------------------
-
-impl AngularUnits for Coor2D {
-    /// Transform the elements of a `Coor2D` from degrees to radians
-    #[must_use]
-    fn to_radians(self) -> Self {
-        Coor2D([self[0].to_radians(), self[1].to_radians()])
-    }
-
-    /// Transform the elements of a `Coor2D` from radians to degrees
-    #[must_use]
-    fn to_degrees(self) -> Self {
-        Coor2D([self[0].to_degrees(), self[1].to_degrees()])
-    }
-
-    /// Transform the elements of a `Coor2D` from radians to seconds of arc.
-    #[must_use]
-    fn to_arcsec(self) -> Self {
-        Coor2D([self[0].to_degrees() * 3600., self[1].to_degrees() * 3600.])
-    }
-
-    /// Transform the internal lon/lat-in-radians to lat/lon-in-degrees
-    #[must_use]
-    fn to_geo(self) -> Self {
-        Coor2D([self[1].to_degrees(), self[0].to_degrees()])
-    }
-}
-
 // ----- C O N S T R U C T O R S ---------------------------------------------
 
 /// Constructors
@@ -127,62 +98,13 @@ impl Coor2D {
     /// Multiply by a scalar
     #[must_use]
     pub fn scale(&self, factor: f64) -> Coor2D {
-        Coor2D([self[0] * factor, self[1] * factor])
+        Coor2D([self.x() * factor, self.y() * factor])
     }
 
     /// Scalar product
     #[must_use]
     pub fn dot(&self, other: Coor2D) -> f64 {
-        self[0] * other[0] + self[1] * other[1]
-    }
-}
-
-// ----- D I S T A N C E S ---------------------------------------------------
-
-impl Coor2D {
-    /// Euclidean distance between two points in the 2D plane.
-    ///
-    /// Primarily used to compute the distance between two projected points
-    /// in their projected plane. Typically, this distance will differ from
-    /// the actual distance in the real world.
-    ///
-    /// # See also:
-    ///
-    /// [`distance`](crate::ellipsoid::Ellipsoid::distance)
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use geodesy::prelude::*;
-    /// let t = 1000 as f64;
-    /// let p0 = Coor2D::origin();
-    /// let p1 = Coor2D::raw(t, t);
-    /// assert_eq!(p0.hypot2(&p1), t.hypot(t));
-    /// ```
-    #[must_use]
-    pub fn hypot2(&self, other: &Self) -> f64 {
-        (self[0] - other[0]).hypot(self[1] - other[1])
-    }
-
-    /// The Geodesic distance on the default ellipsoid. Mostly a shortcut
-    /// for test authoring
-    pub fn default_ellps_dist(&self, other: &Self) -> f64 {
-        Ellipsoid::default().distance(
-            &Coor4D([self[0], self[1], 0., 0.]),
-            &Coor4D([other[0], other[1], 0., 0.]),
-        )
-    }
-}
-
-impl From<Coor2D> for Coor4D {
-    fn from(c: Coor2D) -> Self {
-        Coor4D([c[0], c[1], 0.0, 0.0])
-    }
-}
-
-impl From<Coor4D> for Coor2D {
-    fn from(xyzt: Coor4D) -> Self {
-        Coor2D([xyzt[0], xyzt[1]])
+        self.x() * other.x() + self.y() * other.y()
     }
 }
 
@@ -193,28 +115,28 @@ mod tests {
     use super::*;
     #[test]
     fn distances() {
+        let e = Ellipsoid::default();
         let lat = angular::dms_to_dd(55, 30, 36.);
         let lon = angular::dms_to_dd(12, 45, 36.);
         let dms = Coor2D::geo(lat, lon);
         let geo = Coor2D::geo(55.51, 12.76);
-        assert!(geo.default_ellps_dist(&dms) < 1e-10);
+        assert!(e.distance(&geo, &dms) < 1e-10);
     }
 
     #[test]
     fn coor2d() {
         let c = Coor2D::raw(12., 55.).to_radians();
         let d = Coor2D::gis(12., 55.);
         assert_eq!(c, d);
-        assert_eq!(d[0], 12f64.to_radians());
-        let e = d.to_degrees();
-        assert_eq!(e[0], c.to_degrees()[0]);
+        assert_eq!(d.x(), 12f64.to_radians());
+        assert_eq!(d.x().to_degrees(), c.x().to_degrees());
     }
 
     #[test]
     fn array() {
         let b = Coor2D::raw(7., 8.);
-        let c = [b[0], b[1], f64::NAN, f64::NAN];
-        assert_eq!(b[0], c[0]);
+        let c = [b.x(), b.y(), f64::NAN, f64::NAN];
+        assert_eq!(b.x(), c[0]);
     }
 
     #[test]