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use std::mem::MaybeUninit; /// Convert degrees to radians /// /// ``` /// use libh3::degs_to_rads; /// assert_eq!(2.413790355508158, degs_to_rads(138.3)); /// ``` pub fn degs_to_rads(degrees: f64) -> f64 { unsafe { libh3_sys::degsToRads(degrees) } } /// Convert radians to degrees /// /// ``` /// use libh3::rads_to_degs; /// assert_eq!(138.3, rads_to_degs(2.413790355508158)); /// ``` pub fn rads_to_degs(radians: f64) -> f64 { unsafe { libh3_sys::radsToDegs(radians) } } /// Represent a coordinate #[derive(Debug)] pub struct GeoCoord { // The latitute of the coordinate, typcially this should be specified using // radians but it is easy to convert using [degs_to_rads](degs_to_rads) pub lat: f64, // The longitude of the coordinate, typcially this should be specified using // radians but it is easy to convert using [degs_to_rads](degs_to_rads) pub lon: f64, } impl GeoCoord { /// Create a new GeoCoord representing a coordinate /// /// # Arguments /// /// * `lat` - The latitude of the coordinate /// * `long` - The longitude of the coordinate /// pub fn new(lat: f64, lon: f64) -> GeoCoord { GeoCoord { lat, lon } } } impl From<&GeoCoord> for libh3_sys::GeoCoord { fn from(coord: &GeoCoord) -> Self { libh3_sys::GeoCoord { lat: coord.lat, lon: coord.lon, } } } /// A H3 index value a unique address of a hexagon or more unlikely /// a pentagon. pub type H3Index = libh3_sys::H3Index; /// A resolution that ranges from 0 to 15. /// /// See the [resolution table](https://h3geo.org/docs/core-library/restable) /// for the sizes of resolution. pub type Resolution = u8; /// Return the edge length of a hexagon at a particular resolution in kilometers. /// /// ``` /// use libh3::edge_length_km; /// assert_eq!(edge_length_km(5), 8.544408276); /// ``` pub fn edge_length_km(resolution: Resolution) -> f64 { unsafe { libh3_sys::edgeLengthKm(resolution as i32) } } /// Return the number of hexagons at a particular resolution. /// /// ``` /// use libh3::num_hexagons; /// assert_eq!(num_hexagons(5), 2016842); /// ``` pub fn num_hexagons(resolution: Resolution) -> u64 { unsafe { libh3_sys::numHexagons(resolution as i32) as u64 } } /// Return the edge length of a hexagon at a particular resolution in meters. /// /// ``` /// use libh3::edge_length_m; /// assert_eq!(edge_length_m(5), 8544.408276); /// ``` pub fn edge_length_m(resolution: Resolution) -> f64 { unsafe { libh3_sys::edgeLengthM(resolution as i32) } } /// Convert a GeoCoord to a H3 index. /// /// ``` /// use libh3::{GeoCoord, degs_to_rads, geo_to_h3}; /// let coords = GeoCoord { /// lat: degs_to_rads(40.689167), /// lon: degs_to_rads(-74.044444), /// }; /// /// let v = geo_to_h3(&coords, 10); /// assert_eq!(v.unwrap(), 0x8a2a1072b59ffff); /// ``` pub fn geo_to_h3(coord: &GeoCoord, resolution: Resolution) -> Result<H3Index, ()> { unsafe { match libh3_sys::geoToH3(&libh3_sys::GeoCoord::from(coord), resolution as i32) { 0 => Err(()), x => Ok(x), } } } /// Convert a H3 index value to a GeoCoord /// /// ``` /// use libh3::h3_to_geo; /// let r = h3_to_geo(0x8a2a1072b59ffff); /// assert_eq!(r.lat, 0.7101643819054542); /// assert_eq!(r.lon, -1.2923191206954798); /// ``` pub fn h3_to_geo(h3: H3Index) -> GeoCoord { let result = unsafe { let mut result: MaybeUninit<libh3_sys::GeoCoord> = MaybeUninit::uninit().assume_init(); libh3_sys::h3ToGeo(h3, result.as_mut_ptr()); result.assume_init() }; GeoCoord::new(result.lat, result.lon) } type GeoBoundary = Vec<GeoCoord>; /// Convert a H3 index value to a GeoBoundary which are a /// vector of points that describe a H3 Index's boundary /// /// ``` /// use libh3::h3_to_geo_boundary; /// let foo = h3_to_geo_boundary(0x8a2a1072b59ffff); /// assert_eq!(foo.len(), 6); /// ``` pub fn h3_to_geo_boundary(h3: H3Index) -> GeoBoundary { unsafe { let mut boundary_result: MaybeUninit<libh3_sys::GeoBoundary> = MaybeUninit::uninit().assume_init(); libh3_sys::h3ToGeoBoundary(h3, boundary_result.as_mut_ptr()); let boundary = boundary_result.assume_init(); let mut result = Vec::with_capacity(boundary.numVerts as usize); for i in 0..boundary.numVerts as usize { result.push(GeoCoord::new(boundary.verts[i].lat, boundary.verts[i].lon)); } result } } /// Return the resolution of a H3 index /// /// ``` /// use libh3::{GeoCoord, degs_to_rads, geo_to_h3, h3_get_resolution }; /// let coords = GeoCoord::new( /// degs_to_rads(40.689167), /// degs_to_rads(-74.044444), /// ); /// /// let v = geo_to_h3(&coords, 10); /// assert_eq!(h3_get_resolution(v.unwrap()), 10); /// ```` pub fn h3_get_resolution(h3: H3Index) -> Resolution { unsafe { libh3_sys::h3GetResolution(h3) as Resolution } } /// Determine if H3 index is valid /// /// ``` /// use libh3::{GeoCoord, degs_to_rads, geo_to_h3, h3_is_valid}; /// let coords = GeoCoord { /// lat: degs_to_rads(40.689167), /// lon: degs_to_rads(-74.044444), /// }; /// /// let v = geo_to_h3(&coords, 10); /// assert_eq!(h3_is_valid(v.unwrap()),true); /// ``` pub fn h3_is_valid(h3: H3Index) -> bool { unsafe { match libh3_sys::h3IsValid(h3) { 0 => false, _ => true, } } } /// Determine if two H3 indexes are neighbors /// /// ``` /// use libh3::{GeoCoord, degs_to_rads, geo_to_h3, h3_indexes_are_neighbors}; /// let coords = GeoCoord { /// lat: degs_to_rads(40.689167), /// lon: degs_to_rads(-74.044444), /// }; /// /// let v = geo_to_h3(&coords, 10); /// assert_eq!(h3_indexes_are_neighbors(v.unwrap(), v.unwrap()), false); /// ``` pub fn h3_indexes_are_neighbors(origin: H3Index, destination: H3Index) -> bool { unsafe { match libh3_sys::h3IndexesAreNeighbors(origin, destination) { 0 => false, _ => true, } } } /// Determine the area of a hexagon at a particular resolution. /// /// ``` /// use libh3::{ hex_area_km_2}; /// assert_eq!(hex_area_km_2(10), 0.0150475); /// ``` pub fn hex_area_km_2(resolution: i32) -> f64 { unsafe { libh3_sys::hexAreaKm2(resolution) } } /// Determine if the specified H3 index is a pentagon. /// ``` /// assert_eq!(libh3::h3_is_pentagon(0x8a2a1072b59ffff), false); /// ``` pub fn h3_is_pentagon(h3: H3Index) -> bool { unsafe { match libh3_sys::h3IsPentagon(h3) { 0 => false, _ => true, } } } /// Get the number of the base cell for a given H3 index /// /// ``` /// use libh3; /// assert_eq!(libh3::h3_get_base_cell(0x8a2a1072b59ffff), 21); /// ``` pub fn h3_get_base_cell(h3: H3Index) -> i32 { unsafe { libh3_sys::h3GetBaseCell(h3) } } /// Get all hexagons in a k-ring around a given center. The order of the hexagons is undefined. /// /// # Arguments /// /// * `origin` - The center of the ring. /// * `radius` - The radis of the ring in hexagons, which is the same resolution as the origin. /// /// ``` /// let expected_kring = vec![ /// 0x8a2a1072b59ffff, /// 0x8a2a1072b597fff, /// 0x8a2a1070c96ffff, /// 0x8a2a1072b4b7fff, /// 0x8a2a1072b4a7fff, /// 0x8a2a1072b58ffff, /// 0x8a2a1072b587fff, /// ]; /// let r = libh3::k_ring(0x8a2a1072b59ffff, 1); /// assert_eq!(r, expected_kring); /// ``` pub fn k_ring(origin: H3Index, radius: i32) -> Vec<H3Index> { unsafe { let max = libh3_sys::maxKringSize(radius); let mut r = Vec::<H3Index>::with_capacity(max as usize); libh3_sys::kRing(origin, radius, r.as_mut_ptr()); r.set_len(max as usize); r = r.into_iter().filter(|v| *v != 0).collect(); r } } /// Get all hexagons in a k-ring around a given center, in an array of arrays /// ordered by distance from the origin. The order of the hexagons within each ring is undefined. /// /// # Arguments /// /// * `origin` - The center of the ring. /// * `radius` - The radis of the ring in hexagons, which is the same resolution as the origin. /// /// ``` /// let expected_kring_distances = vec![ /// (0x8a2a1072b59ffff, 0), /// (0x8a2a1072b597fff, 1), /// (0x8a2a1070c96ffff, 1), /// (0x8a2a1072b4b7fff, 1), /// (0x8a2a1072b4a7fff, 1), /// (0x8a2a1072b58ffff, 1), /// (0x8a2a1072b587fff, 1), /// ]; /// let r = libh3::k_ring_distances(0x8a2a1072b59ffff, 1); /// assert_eq!(r, expected_kring_distances); /// ``` pub fn k_ring_distances(origin: H3Index, radius: i32) -> Vec<(H3Index, i32)> { unsafe { let max = libh3_sys::maxKringSize(radius); let mut indexes = Vec::<H3Index>::with_capacity(max as usize); let mut distances = Vec::<i32>::with_capacity(max as usize); libh3_sys::kRingDistances(origin, radius, indexes.as_mut_ptr(), distances.as_mut_ptr()); indexes.set_len(max as usize); distances.set_len(max as usize); indexes .into_iter() .zip(distances.into_iter()) .filter(|v| v.0 != 0) .collect::<Vec<(H3Index, i32)>>() } } pub fn hex_range(origin: H3Index, k: i32) -> (bool, Vec<H3Index>) { unsafe { let max = libh3_sys::maxKringSize(k); let mut r = Vec::<H3Index>::with_capacity(max as usize); let distortion = libh3_sys::hexRange(origin, k, r.as_mut_ptr()); r.set_len(max as usize); r = r.into_iter().filter(|v| *v != 0).collect(); (distortion == 0, r) } } pub fn hex_range_distances(origin: H3Index, k: i32) -> (bool, Vec<(H3Index, i32)>) { unsafe { let max = libh3_sys::maxKringSize(k); let mut indexes = Vec::<H3Index>::with_capacity(max as usize); let mut distances = Vec::<i32>::with_capacity(max as usize); let distortion = libh3_sys::hexRangeDistances(origin, k, indexes.as_mut_ptr(), distances.as_mut_ptr()); indexes.set_len(max as usize); distances.set_len(max as usize); ( distortion == 0, indexes .into_iter() .zip(distances.into_iter()) .filter(|v| v.0 != 0) .collect::<Vec<(H3Index, i32)>>(), ) } } /// Get the grid distance between two hex indexes. This function may fail /// to find the distance between two indexes if they are very far apart or /// on opposite sides of a pentagon. /// # Arguments /// /// * `origin` - The starting H3 index /// * `end` - The ending H3 index /// /// ``` /// use libh3::h3_distance; /// assert_eq!(h3_distance(0x8a2a1072b4a7fff, 0x8a2a1072b58ffff), Ok(1)); /// ``` pub fn h3_distance(origin: H3Index, end: H3Index) -> Result<i32, ()> { unsafe { let r = libh3_sys::h3Distance(origin, end); if r < 0 { Err(()) } else { Ok(r) } } } /// Get all hexagons with centers contained in a given polygon. The polygon /// is specified with GeoJson semantics as an array of loops. The first loop /// is the perimeter of the polygon, and subsequent loops are /// expected to be holes. /// /// # Arguments /// /// * `polygon` - The vector of polygons. /// * `resolution` - The resolution of the generated hexagons /// /// ``` /// use libh3::{polyfill, GeoCoord, degs_to_rads}; /// /// Some vertexes around San Francisco /// let sf_verts = vec![ /// (0.659966917655, -2.1364398519396), /// (0.6595011102219, -2.1359434279405), /// (0.6583348114025, -2.1354884206045), /// (0.6581220034068, -2.1382437718946), /// (0.6594479998527, -2.1384597563896), /// (0.6599990002976, -2.1376771158464), /// ] /// .iter() /// .map(|v| GeoCoord::new(v.0, v.1)) /// .collect(); /// /// let h = polyfill(&vec![sf_verts], 9); /// assert_eq!(h.len(), 1253); /// /// /// /// Fill a polygon around Wellington, NZ /// /// Coordinates are in GeoJSON lon, lat order. /// /// let wellington_verts: Vec<GeoCoord> = vec![ /// (174.800937866947, -41.22501356278325), /// (174.8079721211159, -41.226732341115365), /// (174.82262997231396, -41.231639803277986), /// (174.83561105648377, -41.23873115217201), /// (174.84634815587896, -41.24769587535717), /// (174.85069634833735, -41.252194466801384), /// (174.8587207192276, -41.26264015566857), /// (174.8636809159909, -41.27410982273725), /// (174.86536017144866, -41.28610182569948), /// (174.8653611411562, -41.29165993179072), /// (174.8636858034186, -41.30364998147521), /// (174.85872883206798, -41.31511423541933), /// (174.8507068877321, -41.32555201329627), /// (174.846359294586, -41.33004662498431), /// (174.8356222320399, -41.33900220579377), /// (174.82263983163466, -41.346084796073406), /// (174.807979604528, -41.35098543989819), /// (174.80094378133927, -41.35270175860709), /// (174.78524618901284, -41.35520670405109), /// (174.76919781098724, -41.35520670405109), /// (174.75350021866086, -41.35270175860712), /// (174.7464643954721, -41.35098543989822), /// (174.7318041683653, -41.346084796073406), /// (174.71882176795995, -41.33900220579369), /// (174.7080847054138, -41.330046624984135), /// (174.70373711226773, -41.32555201329609), /// (174.69571516793187, -41.31511423541913), /// (174.69075819658127, -41.303649981474955), /// (174.68908285884382, -41.29165993179046), /// (174.68908382855136, -41.2861018256992), /// (174.69076308400918, -41.274109822737074), /// (174.69572328077246, -41.26264015566849), /// (174.70374765166264, -41.252194466801384), /// (174.70809584412103, -41.24769587535717), /// (174.71883294351622, -41.23873115217201), /// (174.731814027686, -41.231639803278014), /// (174.746471878884, -41.22673234111539), /// (174.75350613305287, -41.22501356278328), /// (174.7691998725514, -41.222504896122565), /// (174.78524412744844, -41.222504896122565), /// (174.800937866947, -41.22501356278325), /// ].iter().map(|v| GeoCoord::new(degs_to_rads(v.1), degs_to_rads(v.0))).collect(); /// /// let mut h = polyfill(&vec![wellington_verts], 6); /// assert_eq!(h.len(), 5); /// h.sort_unstable(); /// assert_eq!(h, vec![606774924341673983, 606774925281198079, 606774925549633535, 606774929307729919, 606774929441947647]); /// ``` pub fn polyfill(polygon: &[Vec<GeoCoord>], resolution: Resolution) -> Vec<H3Index> { let real_polygon = polygon .iter() .map(|p| p.iter().map(libh3_sys::GeoCoord::from).collect()) .collect::<Vec<Vec<libh3_sys::GeoCoord>>>(); unsafe { let fence = libh3_sys::Geofence { numVerts: real_polygon[0].len() as i32, verts: real_polygon[0].as_ptr(), }; let holes = real_polygon .iter() .skip(1) .map(|p| libh3_sys::Geofence { numVerts: p.len() as i32, verts: p.as_ptr(), }) .collect::<Vec<libh3_sys::Geofence>>(); let p = libh3_sys::GeoPolygon { geofence: fence, numHoles: (real_polygon.len() - 1) as i32, holes: holes.as_ptr(), }; let max = libh3_sys::maxPolyfillSize(&p, resolution as i32); let mut r = Vec::<H3Index>::with_capacity(max as usize); libh3_sys::polyfill(&p, resolution as i32, r.as_mut_ptr()); r.set_len(max as usize); r.retain(|&v| v != 0); r } } /// Returns the size of the array needed by h3ToChildren for these inputs. /// /// # Arguments /// /// * `h` - The index of the parent resolution. /// * `resolution` - The resolution of the desired level. /// /// ``` /// use libh3::max_h3_to_children_size; /// assert_eq!(max_h3_to_children_size(0x852a1073fffffff, 6), 7); /// ``` pub fn max_h3_to_children_size(h: H3Index, resolution: Resolution) -> i32 { unsafe { libh3_sys::maxH3ToChildrenSize(h, resolution as i32) } } /// Returns the parent (coarser) index containing h3. /// /// # Arguments /// /// * `h` - The index of the child resolution. /// * `resolution` - The resolution of the desired level. /// /// ``` /// use libh3::h3_to_parent; /// assert_eq!(h3_to_parent(0x8a2a1072b4a7fff, 5), 0x852a1073fffffff); /// ``` pub fn h3_to_parent(h: H3Index, resolution: Resolution) -> H3Index { unsafe { libh3_sys::h3ToParent(h, resolution as i32) } } /// Returns children indexes contained by the given index at the given resolution. /// /// # Arguments /// /// * `h` - The index of the child resolution. /// * `resolution` - The resolution of the desired level. /// /// ``` /// use libh3::h3_to_children; /// assert_eq!( /// h3_to_children(0x852a1073fffffff, 6), /// vec![ /// 0x862a10707ffffff, /// 0x862a1070fffffff, /// 0x862a10717ffffff, /// 0x862a1071fffffff, /// 0x862a10727ffffff, /// 0x862a1072fffffff, /// 0x862a10737ffffff /// ] /// ); /// ``` pub fn h3_to_children(h: H3Index, resolution: Resolution) -> Vec<H3Index> { let max = max_h3_to_children_size(h, resolution) as usize; let mut result = Vec::<H3Index>::with_capacity(max as usize); unsafe { libh3_sys::h3ToChildren(h, resolution as i32, result.as_mut_ptr()); result.set_len(max as usize); result } } /// Number of resolution 0 H3 indexes. /// /// ``` /// use libh3::res_0_index_count; /// assert_eq!(res_0_index_count(), 122); /// ``` pub fn res_0_index_count() -> i32 { unsafe { libh3_sys::res0IndexCount() } } /// All the resolution 0 H3 indexes. /// /// ``` /// use libh3::get_res_0_indexes; /// assert_eq!( /// get_res_0_indexes().len(), /// 122 /// ); /// ``` pub fn get_res_0_indexes() -> Vec<H3Index> { let max = res_0_index_count() as usize; let mut result = Vec::<H3Index>::with_capacity(max as usize); unsafe { libh3_sys::getRes0Indexes(result.as_mut_ptr()); result.set_len(max); result } }