port boolean_point_on_line

lib/turf/boolean_point_on_line.rb

@@ -2,7 +2,127 @@
 
 # :nodoc:
 module Turf
-  def boolean_point_on_line(*args)
-    raise NotImplementedError
+  # Returns true if a point is on a line. Accepts an optional parameter to ignore the
+  # start and end vertices of the linestring.
+  #
+  # @param [Hash] pt GeoJSON Point
+  # @param [Hash] line GeoJSON LineString
+  # @param [Hash] options Optional parameters
+  # @option options [Boolean] :ignore_end_vertices whether to ignore the start and end vertices.
+  # @option options [Float] :epsilon Fractional number to compare with the cross product result.
+  # Useful for dealing with floating points such as lng/lat points
+  # @return [Boolean] true/false
+  # @example
+  #   pt = turf_point([0, 0])
+  #   line = turf_line_string([[-1, -1], [1, 1], [1.5, 2.2]])
+  #   is_point_on_line = boolean_point_on_line(pt, line)
+  #   # => true
+  def boolean_point_on_line(point, line, options = nil)
+    options ||= {}
+    # Normalize inputs
+    pt_coords = get_coord(point)
+    line_coords = get_coords(line)
+
+    # Main
+    line_coords.each_cons(2) do |line_segment_start, line_segment_end|
+      ignore_boundary = false
+      if options[:ignore_end_vertices]
+        first_segment = (line_coords.first == line_segment_start)
+        last_segment = (line_coords.last == line_segment_end)
+
+        if first_segment && last_segment
+          ignore_boundary = :both
+        elsif first_segment
+          ignore_boundary = :start
+        elsif last_segment
+          ignore_boundary = :end
+        end
+      end
+
+      return true if is_point_on_line_segment(
+        line_segment_start,
+        line_segment_end,
+        pt_coords,
+        ignore_boundary,
+        options[:epsilon],
+      )
+    end
+
+    false
+  end
+
+  # Determines if a point is on a line segment.
+  #
+  # @param [Array<Float>] line_segment_start Coordinate pair of the start of the line segment [x1, y1].
+  # @param [Array<Float>] line_segment_end Coordinate pair of the end of the line segment [x2, y2].
+  # @param [Array<Float>] pt Coordinate pair of the point to check [px, py].
+  # @param [Boolean, String] exclude_boundary Whether the point is allowed to fall on the line ends.
+  # Can be true, false, or one of "start", "end", or "both".
+  # @param [Float, NilClass] epsilon Fractional tolerance for cross-product
+  # comparison (useful for floating-point coordinates).
+  # @return [Boolean] true if the point is on the line segment, false otherwise.
+  def is_point_on_line_segment(line_segment_start, line_segment_end, point, exclude_boundary, epsilon = nil)
+    x, y = point
+    x1, y1 = line_segment_start
+    x2, y2 = line_segment_end
+
+    dxc = x - x1
+    dyc = y - y1
+    dxl = x2 - x1
+    dyl = y2 - y1
+    cross = (dxc * dyl) - (dyc * dxl)
+
+    if epsilon
+      return false if cross.abs > epsilon
+    elsif cross != 0
+      return false
+    end
+
+    # Special case: zero-length line segments
+    if dxl == 0 && dyl == 0
+      return false if exclude_boundary
+
+      return point == line_segment_start
+    end
+
+    case exclude_boundary
+    when false
+      if dxl.abs >= dyl.abs
+        if dxl > 0
+          x.between?(x1,
+                     x2)
+        else
+          x.between?(x2,
+                     x1)
+        end
+      else
+        (if dyl > 0
+           y.between?(y1,
+                      y2)
+         else
+           y.between?(y2, y1)
+         end)
+      end
+    when :start
+      if dxl.abs >= dyl.abs
+        dxl > 0 ? x1 < x && x <= x2 : x2 <= x && x < x1
+      else
+        (dyl > 0 ? y1 < y && y <= y2 : y2 < y && y < y1)
+      end
+    when :end
+      if dxl.abs >= dyl.abs
+        dxl > 0 ? x1 <= x && x < x2 : x2 < x && x <= x1
+      else
+        (dyl > 0 ? y1 <= y && y < y2 : y2 < y && y <= y1)
+      end
+    when :both
+      if dxl.abs >= dyl.abs
+        dxl > 0 ? x1 < x && x < x2 : x2 < x && x < x1
+      else
+        (dyl > 0 ? y1 < y && y < y2 : y2 < y && y < y1)
+      end
+    else
+      false
+    end
   end
 end

test/boolean_point_on_line/false/LineWithOnly1SegmentIgnoreBoundary.geojson

@@ -0,0 +1,27 @@
+{
+  "type": "FeatureCollection",
+  "properties": {
+    "ignore_end_vertices": true
+  },
+  "features": [
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "Point",
+        "coordinates": [0, 0]
+      }
+    },
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "LineString",
+        "coordinates": [
+          [0, 0],
+          [3, 3]
+        ]
+      }
+    }
+  ]
+}

test/boolean_point_on_line/false/LineWithOnly1SegmentIgnoreBoundaryEnd.geojson

@@ -0,0 +1,27 @@
+{
+  "type": "FeatureCollection",
+  "properties": {
+    "ignore_end_vertices": true
+  },
+  "features": [
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "Point",
+        "coordinates": [3, 3]
+      }
+    },
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "LineString",
+        "coordinates": [
+          [0, 0],
+          [3, 3]
+        ]
+      }
+    }
+  ]
+}

test/boolean_point_on_line/false/PointIsOnLineButFailsWithSmallEpsilonValue.geojson

@@ -0,0 +1,27 @@
+{
+  "type": "FeatureCollection",
+  "properties": {
+    "epsilon": 10e-18
+  },
+  "features": [
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "Point",
+        "coordinates": [-75.25737143565107, 39.99673377198139]
+      }
+    },
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "LineString",
+        "coordinates": [
+          [-75.2580499870244, 40.00180204907801],
+          [-75.25676601413157, 39.992211720827044]
+        ]
+      }
+    }
+  ]
+}

test/boolean_point_on_line/false/PointIsOnLineButFailsWithoutEpsilonForBackwardsCompatibility.geojson

@@ -0,0 +1,24 @@
+{
+  "type": "FeatureCollection",
+  "features": [
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "Point",
+        "coordinates": [-75.25737143565107, 39.99673377198139]
+      }
+    },
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "LineString",
+        "coordinates": [
+          [-75.2580499870244, 40.00180204907801],
+          [-75.25676601413157, 39.992211720827044]
+        ]
+      }
+    }
+  ]
+}

test/boolean_point_on_line/false/PointOnEndFailsWhenIgnoreEndpoints.geojson

@@ -0,0 +1,28 @@
+{
+  "type": "FeatureCollection",
+  "properties": {
+    "ignore_end_vertices": true
+  },
+  "features": [
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "Point",
+        "coordinates": [38.3203125, 5.965753671065536]
+      }
+    },
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "LineString",
+        "coordinates": [
+          [0, 0],
+          [3, 3],
+          [38.3203125, 5.965753671065536]
+        ]
+      }
+    }
+  ]
+}

test/boolean_point_on_line/false/PointOnStartFailsWhenIgnoreEndpoints.geojson

@@ -0,0 +1,28 @@
+{
+  "type": "FeatureCollection",
+  "properties": {
+    "ignore_end_vertices": true
+  },
+  "features": [
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "Point",
+        "coordinates": [0, 0]
+      }
+    },
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "LineString",
+        "coordinates": [
+          [0, 0],
+          [3, 3],
+          [38.3203125, 5.965753671065536]
+        ]
+      }
+    }
+  ]
+}

test/boolean_point_on_line/false/notOnLine.geojson

@@ -0,0 +1,28 @@
+{
+  "type": "FeatureCollection",
+  "properties": {
+    "ignore_end_vertices": true
+  },
+  "features": [
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "Point",
+        "coordinates": [20, 20]
+      }
+    },
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "LineString",
+        "coordinates": [
+          [0, 0],
+          [3, 3],
+          [38.3203125, 5.965753671065536]
+        ]
+      }
+    }
+  ]
+}

test/boolean_point_on_line/true/LineWithOnly1Segment.geojson

@@ -0,0 +1,27 @@
+{
+  "type": "FeatureCollection",
+  "properties": {
+    "ignore_end_vertices": true
+  },
+  "features": [
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "Point",
+        "coordinates": [1, 1]
+      }
+    },
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "LineString",
+        "coordinates": [
+          [0, 0],
+          [3, 3]
+        ]
+      }
+    }
+  ]
+}

test/boolean_point_on_line/true/LineWithOnly1SegmentOnStart.geojson

@@ -0,0 +1,24 @@
+{
+  "type": "FeatureCollection",
+  "features": [
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "Point",
+        "coordinates": [0, 0]
+      }
+    },
+    {
+      "type": "Feature",
+      "properties": {},
+      "geometry": {
+        "type": "LineString",
+        "coordinates": [
+          [0, 0],
+          [3, 3]
+        ]
+      }
+    }
+  ]
+}