chore: release v0.0.9

crates/geometry-adapt-geo-types/CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.0.9](https://github.com/pentatonick/boost_geometry/compare/geometry-adapt-geo-types-v0.0.8...geometry-adapt-geo-types-v0.0.9) - 2026-09-05
+
+### Other
+
+- updated the following local packages: geometry-coords, geometry-cs, geometry-trait, geometry-model
+
 ## [0.0.8](https://github.com/pentatonick/boost_geometry/compare/geometry-adapt-geo-types-v0.0.7...geometry-adapt-geo-types-v0.0.8) - 2026-07-15
 
 ### Other

crates/geometry-adapt-geo-types/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "geometry-adapt-geo-types"
-version                = "0.0.8"
+version                = "0.0.9"
 edition.workspace      = true
 rust-version.workspace = true
 license.workspace      = true
@@ -12,10 +12,10 @@ readme = "README.md"
 
 [dependencies]
 geometry-tag    = { version = "0.0.7", path = "../geometry-tag" }
-geometry-coords = { version = "0.0.8", path = "../geometry-coords" }
-geometry-cs     = { version = "0.0.8", path = "../geometry-cs" }
-geometry-trait  = { version = "0.0.8", path = "../geometry-trait" }
-geometry-model  = { version = "0.0.8", path = "../geometry-model" }
+geometry-coords = { version = "0.0.9", path = "../geometry-coords" }
+geometry-cs     = { version = "0.0.9", path = "../geometry-cs" }
+geometry-trait  = { version = "0.0.9", path = "../geometry-trait" }
+geometry-model  = { version = "0.0.9", path = "../geometry-model" }
 geo-types       = "0.7"
 
 [dev-dependencies]

crates/geometry-adapt-nalgebra/CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.0.9](https://github.com/pentatonick/boost_geometry/compare/geometry-adapt-nalgebra-v0.0.8...geometry-adapt-nalgebra-v0.0.9) - 2026-09-05
+
+### Other
+
+- updated the following local packages: geometry-coords, geometry-cs, geometry-trait
+
 ## [0.0.8](https://github.com/pentatonick/boost_geometry/compare/geometry-adapt-nalgebra-v0.0.7...geometry-adapt-nalgebra-v0.0.8) - 2026-07-15
 
 ### Other

crates/geometry-adapt-nalgebra/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "geometry-adapt-nalgebra"
-version                = "0.0.8"
+version                = "0.0.9"
 edition.workspace      = true
 rust-version.workspace = true
 license.workspace      = true
@@ -12,9 +12,9 @@ readme = "README.md"
 
 [dependencies]
 geometry-tag    = { version = "0.0.7", path = "../geometry-tag" }
-geometry-coords = { version = "0.0.8", path = "../geometry-coords" }
-geometry-cs     = { version = "0.0.8", path = "../geometry-cs" }
-geometry-trait  = { version = "0.0.8", path = "../geometry-trait" }
+geometry-coords = { version = "0.0.9", path = "../geometry-coords" }
+geometry-cs     = { version = "0.0.9", path = "../geometry-cs" }
+geometry-trait  = { version = "0.0.9", path = "../geometry-trait" }
 nalgebra        = "0.32"
 
 [dev-dependencies]

crates/geometry-adapt/CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.0.9](https://github.com/pentatonick/boost_geometry/compare/geometry-adapt-v0.0.8...geometry-adapt-v0.0.9) - 2026-09-05
+
+### Other
+
+- updated the following local packages: geometry-coords, geometry-cs, geometry-trait
+
 ## [0.0.8](https://github.com/pentatonick/boost_geometry/compare/geometry-adapt-v0.0.7...geometry-adapt-v0.0.8) - 2026-07-15
 
 ### Other

crates/geometry-adapt/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "geometry-adapt"
-version                = "0.0.8"
+version                = "0.0.9"
 edition.workspace      = true
 rust-version.workspace = true
 license.workspace      = true
@@ -24,9 +24,9 @@ libm = [
 
 [dependencies]
 geometry-tag    = { version = "0.0.7", path = "../geometry-tag" }
-geometry-coords = { version = "0.0.8", path = "../geometry-coords", default-features = false }
-geometry-cs     = { version = "0.0.8", path = "../geometry-cs",     default-features = false }
-geometry-trait  = { version = "0.0.8", path = "../geometry-trait",  default-features = false }
+geometry-coords = { version = "0.0.9", path = "../geometry-coords", default-features = false }
+geometry-cs     = { version = "0.0.9", path = "../geometry-cs",     default-features = false }
+geometry-trait  = { version = "0.0.9", path = "../geometry-trait",  default-features = false }
 
 [dev-dependencies]
 geometry-algorithm = { path = "../geometry-algorithm" }

crates/geometry-algorithm/CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.0.9](https://github.com/pentatonick/boost_geometry/compare/geometry-algorithm-v0.0.8...geometry-algorithm-v0.0.9) - 2026-09-05
+
+### Fixed
+
+- *(coords)* two points within an epsilon are one point
+- *(algorithm)* collapse repeated vertices in remove_spikes
+
 ## [0.0.8](https://github.com/pentatonick/boost_geometry/compare/geometry-algorithm-v0.0.7...geometry-algorithm-v0.0.8) - 2026-07-15
 
 ### Added

crates/geometry-algorithm/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "geometry-algorithm"
-version                = "0.0.8"
+version                = "0.0.9"
 edition.workspace      = true
 rust-version.workspace = true
 license.workspace      = true
@@ -27,12 +27,12 @@ libm = [
 ]
 
 [dependencies]
-geometry-coords   = { version = "0.0.8", path = "../geometry-coords",   default-features = false }
+geometry-coords   = { version = "0.0.9", path = "../geometry-coords",   default-features = false }
 geometry-tag      = { version = "0.0.7", path = "../geometry-tag",      default-features = false }
-geometry-cs       = { version = "0.0.8", path = "../geometry-cs",       default-features = false }
-geometry-trait    = { version = "0.0.8", path = "../geometry-trait",    default-features = false }
-geometry-strategy = { version = "0.0.8", path = "../geometry-strategy", default-features = false }
-geometry-model    = { version = "0.0.8", path = "../geometry-model",    default-features = false }
+geometry-cs       = { version = "0.0.9", path = "../geometry-cs",       default-features = false }
+geometry-trait    = { version = "0.0.9", path = "../geometry-trait",    default-features = false }
+geometry-strategy = { version = "0.0.9", path = "../geometry-strategy", default-features = false }
+geometry-model    = { version = "0.0.9", path = "../geometry-model",    default-features = false }
 
 [dev-dependencies]
 geometry-adapt    = { path = "../geometry-adapt" }

crates/geometry-algorithm/src/remove_spikes.rs

@@ -1,11 +1,15 @@
 //! `remove_spikes(&mut g)` — drop collinear-and-reversed vertices.
 //!
 //! Mirrors `boost::geometry::remove_spikes` from
-//! `boost/geometry/algorithms/remove_spikes.hpp`. A spike is a triple
-//! `(a, b, c)` where `(b-a) × (c-b) == 0` (collinear) AND
-//! `(b-a) · (c-b) < 0` (reversed). The middle vertex `b` is removed;
-//! the walk repeats until no spike remains, because collapsing one
-//! spike can create a new one at the now-adjacent pair.
+//! `boost/geometry/algorithms/remove_spikes.hpp`. The predicate is
+//! Boost's `point_is_spike_or_equal`, and the `or_equal` half carries
+//! its weight: a triple `(a, b, c)` qualifies when `(b-a) × (c-b) == 0`
+//! (collinear) and `(b-a) · (c-b) <= 0`, which covers both a reversal
+//! and a zero-length step — that is, a repeated vertex. The middle
+//! vertex `b` is removed; the walk repeats until nothing qualifies,
+//! because collapsing one spike can create a new one at the
+//! now-adjacent pair, and peeling a spike off a ring routinely leaves a
+//! repeated vertex behind.
 //!
 //! Per-kind:
 //! * `Linestring`, `Ring`  → spike-walk the backing `Vec<P>`
@@ -34,17 +38,41 @@ pub trait RemoveSpikes {
     fn remove_spikes(&mut self);
 }
 
-/// True iff `b` is a spike between `a` and `c` (2D cross `== 0` AND
-/// dot `< 0`).
-fn is_spike_2d<P: PointTrait>(a: &P, b: &P, c: &P) -> bool {
+/// True iff `b` is a spike between `a` and `c`, **or** duplicates one of
+/// them: 2D cross `== 0` and dot `<= 0`.
+///
+/// Mirrors `detail::point_is_spike_or_equal`
+/// (`algorithms/detail/point_is_spike_or_equal.hpp`). Requiring `dot < 0`
+/// instead would leave every repeated vertex in place, including the ones
+/// this function creates: removing the apex of `(4,0) (6,0) (4,0)` leaves
+/// `(4,0) (4,0)` adjacent, and Boost collapses that.
+///
+/// `dot <= 0` cannot over-match. Two non-zero vectors that are both
+/// parallel (`cross == 0`) and perpendicular (`dot == 0`) do not exist, so
+/// the equality arm fires only when one of the steps has zero length.
+fn is_spike_or_equal_2d<P: PointTrait>(a: &P, b: &P, c: &P) -> bool {
     let ux = b.get::<0>() - a.get::<0>();
     let uy = b.get::<1>() - a.get::<1>();
     let vx = c.get::<0>() - b.get::<0>();
     let vy = c.get::<1>() - b.get::<1>();
     let cross = ux * vy - uy * vx;
     let dot = ux * vx + uy * vy;
     let zero = <P::Scalar as CoordinateScalar>::ZERO;
-    cross == zero && dot < zero
+    // The collinearity half is Boost's `side_by_triangle`, which calls three
+    // points collinear whenever any *two* of them are equal by `math::equals`
+    // — a relative epsilon — before it looks at any determinant
+    // (`side_by_triangle.hpp:150-164`). A hairline whose two ends are a few
+    // last bits apart at a large coordinate is a spike to Boost and a genuine
+    // sliver to an exact cross product, which is how one survived into a tile
+    // that the reference drew as nothing.
+    let same = |ax: P::Scalar, ay: P::Scalar, bx: P::Scalar, by: P::Scalar| {
+        ax.tolerant_eq(bx) && ay.tolerant_eq(by)
+    };
+    let collinear = cross == zero
+        || same(a.get::<0>(), a.get::<1>(), b.get::<0>(), b.get::<1>())
+        || same(a.get::<0>(), a.get::<1>(), c.get::<0>(), c.get::<1>())
+        || same(b.get::<0>(), b.get::<1>(), c.get::<0>(), c.get::<1>());
+    collinear && dot <= zero
 }
 
 fn walk_spikes<P: PointTrait>(pts: &mut alloc::vec::Vec<P>) {
@@ -53,7 +81,7 @@ fn walk_spikes<P: PointTrait>(pts: &mut alloc::vec::Vec<P>) {
         changed = false;
         let mut i = 1;
         while i + 1 < pts.len() {
-            if is_spike_2d(&pts[i - 1], &pts[i], &pts[i + 1]) {
+            if is_spike_or_equal_2d(&pts[i - 1], &pts[i], &pts[i + 1]) {
                 pts.remove(i);
                 changed = true;
                 // Do not advance `i`: the new `pts[i]` (was `pts[i+1]`)
@@ -105,12 +133,14 @@ fn walk_ring_spikes<P: PointTrait + Copy>(pts: &mut alloc::vec::Vec<P>, closed:
     while found {
         found = false;
         // Spike at the first point: (prev = back-1, back, front).
-        while pts.len() >= 3 && is_spike_2d(&pts[pts.len() - 2], &pts[pts.len() - 1], &pts[0]) {
+        while pts.len() >= 3
+            && is_spike_or_equal_2d(&pts[pts.len() - 2], &pts[pts.len() - 1], &pts[0])
+        {
             pts.pop();
             found = true;
         }
         // Spike at the second point: (back, front, front+1).
-        while pts.len() >= 3 && is_spike_2d(&pts[pts.len() - 1], &pts[0], &pts[1]) {
+        while pts.len() >= 3 && is_spike_or_equal_2d(&pts[pts.len() - 1], &pts[0], &pts[1]) {
             pts.remove(0);
             found = true;
         }
@@ -160,11 +190,54 @@ mod tests {
 
     use super::remove_spikes;
     use geometry_cs::Cartesian;
-    use geometry_model::{Point2D, linestring};
-    use geometry_trait::Linestring as _;
+    use geometry_model::{Point2D, Ring, linestring};
+    use geometry_trait::{Linestring as _, Point as _, Ring as _};
 
     type P = Point2D<f64, Cartesian>;
 
+    fn spike_ring(points: &[(f64, f64)]) -> Ring<P> {
+        let mut ring = Ring::new();
+        for &(x, y) in points {
+            ring.push(P::new(x, y));
+        }
+        ring
+    }
+
+    /// A hairline whose two ends are four last bits apart at a coordinate of
+    /// 3540, which is inside one epsilon of it.
+    ///
+    /// C++: `side_by_triangle` calls three points collinear when any two of
+    /// them are `math::equals` — a *relative* epsilon — before it computes any
+    /// determinant, so Boost sees a spike here and collapses the ring to a
+    /// single repeated point. An exact cross product sees a sliver with real
+    /// area and keeps it, which is how one survived into a monaco tile the
+    /// reference drew as nothing.
+    #[test]
+    fn a_hairline_within_an_epsilon_is_a_spike() {
+        let mut ring = spike_ring(&[
+            (3_539.999_999_999_999_5, 482.199_999_999_999_76),
+            (3540.0, 482.199_999_999_999_8),
+            (3540.0, 479.0),
+            (3_539.999_999_999_999_5, 482.199_999_999_999_76),
+        ]);
+        remove_spikes(&mut ring);
+        assert_eq!(ring.0.len(), 2, "{:?}", ring.0);
+    }
+
+    /// The same ring with its two ends far enough apart to be two points,
+    /// where the sliver has real area and stays.
+    #[test]
+    fn a_sliver_wider_than_an_epsilon_is_kept() {
+        let mut ring = spike_ring(&[
+            (3_539.999_999_9, 482.199_999_9),
+            (3540.0, 482.2),
+            (3540.0, 479.0),
+            (3_539.999_999_9, 482.199_999_9),
+        ]);
+        remove_spikes(&mut ring);
+        assert_eq!(ring.0.len(), 4, "{:?}", ring.0);
+    }
+
     #[test]
     fn out_and_back_spur_is_removed() {
         // (0,0) → (1,0) → (3,0) → (2,0): the tip (3,0) is a reversed
@@ -306,4 +379,96 @@ mod tests {
         assert!(r.points().count() >= 4);
         assert_eq!(pts.first(), pts.last(), "ring must remain closed");
     }
+
+    /// Boost collapses a repeated vertex the same way it collapses a
+    /// spike — `point_is_spike_or_equal` covers both. Expected values from
+    /// `boost::geometry::remove_spikes` on a clockwise `model::polygon`
+    /// (Boost 1.83):
+    ///
+    /// ```text
+    /// consecutive dup  -> (0,0) (0,4) (4,4) (4,0) (0,0)
+    /// dup at start     -> (0,0) (0,4) (4,4) (4,0) (0,0)
+    /// triple dup       -> (0,0) (0,4) (4,4) (4,0) (0,0)
+    /// real spike       -> (0,0) (0,4) (4,4) (4,0) (0,0)
+    /// dup + spike      -> (0,0) (0,4) (4,4) (4,0) (0,0)
+    /// ```
+    ///
+    /// The `real spike` row is the one that shows why: removing the apex
+    /// of `(4,0) (6,0) (4,0)` leaves `(4,0) (4,0)` adjacent, so a
+    /// spike-only predicate makes duplicates out of its own output.
+    #[test]
+    fn repeated_vertices_are_collapsed() {
+        let square = [(0.0, 0.0), (0.0, 4.0), (4.0, 4.0), (4.0, 0.0), (0.0, 0.0)];
+
+        for (name, input) in [
+            (
+                "consecutive dup",
+                vec![
+                    (0.0, 0.0),
+                    (0.0, 4.0),
+                    (4.0, 4.0),
+                    (4.0, 4.0),
+                    (4.0, 0.0),
+                    (0.0, 0.0),
+                ],
+            ),
+            (
+                "dup at start",
+                vec![
+                    (0.0, 0.0),
+                    (0.0, 0.0),
+                    (0.0, 4.0),
+                    (4.0, 4.0),
+                    (4.0, 0.0),
+                    (0.0, 0.0),
+                ],
+            ),
+            (
+                "triple dup",
+                vec![
+                    (0.0, 0.0),
+                    (0.0, 4.0),
+                    (4.0, 4.0),
+                    (4.0, 4.0),
+                    (4.0, 4.0),
+                    (4.0, 0.0),
+                    (0.0, 0.0),
+                ],
+            ),
+            (
+                "real spike",
+                vec![
+                    (0.0, 0.0),
+                    (0.0, 4.0),
+                    (4.0, 4.0),
+                    (4.0, 0.0),
+                    (6.0, 0.0),
+                    (4.0, 0.0),
+                    (0.0, 0.0),
+                ],
+            ),
+            (
+                "dup + spike",
+                vec![
+                    (0.0, 0.0),
+                    (0.0, 4.0),
+                    (4.0, 4.0),
+                    (4.0, 4.0),
+                    (4.0, 0.0),
+                    (6.0, 0.0),
+                    (4.0, 0.0),
+                    (0.0, 0.0),
+                ],
+            ),
+        ] {
+            let mut ring: Ring<P> =
+                Ring::from_vec(input.iter().map(|&(x, y)| P::new(x, y)).collect());
+            remove_spikes(&mut ring);
+            let pts: Vec<(f64, f64)> = ring
+                .points()
+                .map(|p| (p.get::<0>(), p.get::<1>()))
+                .collect();
+            assert_eq!(pts, square, "{name}");
+        }
+    }
 }