progress

gpx-rs/src/utils.rs

@@ -6,11 +6,11 @@ static TO_RADIANS: f64 = PI / 180.0;
 static EARTH_RADIUS: f64 = 6371.0088;
 
 /// Computes the distance in kilometers between two coordinates using the Haversine formula
-pub fn distance(coord1: &LngLat, coord2: &LngLat) -> f64 {
-    let lat1 = coord1.lat * TO_RADIANS;
-    let lat2 = coord2.lat * TO_RADIANS;
+pub fn distance(p1: LngLat, p2: LngLat) -> f64 {
+    let lat1 = p1.lat * TO_RADIANS;
+    let lat2 = p2.lat * TO_RADIANS;
     let delta_lat = lat2 - lat1;
-    let delta_lng = (coord2.lng - coord1.lng) * TO_RADIANS;
+    let delta_lng = (p2.lng - p1.lng) * TO_RADIANS;
 
     let a =
         (delta_lat / 2.0).sin().powi(2) + lat1.cos() * lat2.cos() * (delta_lng / 2.0).sin().powi(2);
@@ -22,3 +22,90 @@ pub fn distance(coord1: &LngLat, coord2: &LngLat) -> f64 {
 pub fn speed(distance: f64, time: i64) -> f64 {
     distance / (time as f64 / 3600_000.0)
 }
+
+pub fn slope(ele: f64, distance: f64) -> f64 {
+    if distance == 0.0 {
+        100.0
+    } else {
+        0.1 * ele / distance
+    }
+}
+
+static METERS_PER_LATITUDE_DEGREE: f64 = 111320.0;
+
+fn get_meters_per_longitude_degree(latitude: f64) -> f64 {
+    ((latitude * PI) / 180.0).cos() * METERS_PER_LATITUDE_DEGREE
+}
+
+// Calculates the point on the line segment defined by p1 and p2
+// that is closest to the third point, p3.
+// Uses simple planar geometry (ignores earth curvature).
+fn projected(p1: LngLat, p2: LngLat, coord3: LngLat) -> LngLat {
+    // Convert to meters using approximate scaling
+    let meters_per_longitude_degree = get_meters_per_longitude_degree(p1.lat);
+
+    let x1 = p1.lng * meters_per_longitude_degree;
+    let y1 = p1.lat * METERS_PER_LATITUDE_DEGREE;
+    let x2 = p2.lng * meters_per_longitude_degree;
+    let y2 = p2.lat * METERS_PER_LATITUDE_DEGREE;
+    let x3 = coord3.lng * meters_per_longitude_degree;
+    let y3 = coord3.lat * METERS_PER_LATITUDE_DEGREE;
+
+    let dx = x2 - x1;
+    let dy = y2 - y1;
+    let segment_length_squared = dx * dx + dy * dy;
+
+    if segment_length_squared == 0.0 {
+        // p1 and p2 are the same point
+        p1
+    } else {
+        // Project p3 onto the line defined by p1-p2
+        let t =
+            0.0_f64.max(1.0_f64.min(((x3 - x1) * dx + (y3 - y1) * dy) / segment_length_squared));
+
+        // Find the closest point on the segment
+        let proj_x = x1 + t * dx;
+        let proj_y = y1 + t * dy;
+
+        // Convert back to degrees
+        LngLat {
+            lng: proj_x / meters_per_longitude_degree,
+            lat: proj_y / METERS_PER_LATITUDE_DEGREE,
+        }
+    }
+}
+
+/// Calculates the perpendicular distance in meters
+/// between a line segment (defined by p1 and p2) and a third point, p3.
+/// Uses simple planar geometry (ignores earth curvature).
+fn crossarc(p1: LngLat, p2: LngLat, p3: LngLat) -> f64 {
+    // Convert to meters using approximate scaling
+    let meters_per_longitude_degree = get_meters_per_longitude_degree(p1.lat);
+
+    let x1 = p1.lng * meters_per_longitude_degree;
+    let y1 = p1.lat * METERS_PER_LATITUDE_DEGREE;
+    let x2 = p2.lng * meters_per_longitude_degree;
+    let y2 = p2.lat * METERS_PER_LATITUDE_DEGREE;
+    let x3 = p3.lng * meters_per_longitude_degree;
+    let y3 = p3.lat * METERS_PER_LATITUDE_DEGREE;
+
+    let dx = x2 - x1;
+    let dy = y2 - y1;
+    let segment_length_squared = dx * dx + dy * dy;
+
+    if segment_length_squared == 0.0 {
+        // p1 and p2 are the same point
+        ((x3 - x1) * (x3 - x1) + (y3 - y1) * (y3 - y1)).sqrt()
+    } else {
+        // Project p3 onto the line defined by p1 - p2
+        let t =
+            0.0_f64.max(1.0_f64.min(((x3 - x1) * dx + (y3 - y1) * dy) / segment_length_squared));
+
+        // Find the closest point on the segment
+        let proj_x = x1 + t * dx;
+        let proj_y = y1 + t * dy;
+
+        // Return distance from p3 to the projected point
+        ((x3 - proj_x) * (x3 - proj_x) + (y3 - proj_y) * (y3 - proj_y)).sqrt()
+    }
+}