@spec centroid(Geo.Polygon.t()) :: Geo.Point.t()

Computes the centroid of a Geo.Polygon as a Geo.Point.

Uses the arithmetic mean of vertices (not area-weighted).

Examples

iex> poly = %Geo.Polygon{coordinates: [[{0,0},{10,0},{10,10},{0,10},{0,0}]]}
iex> centroid = Meridian.Geometry.centroid(poly)
iex> centroid.coordinates
{5.0, 5.0}

@spec contains?(Geo.Polygon.t(), Geo.Point.t()) :: boolean()

Returns true if point lies inside polygon.

Uses a simple ray-casting algorithm. Works for simple polygons.

Examples

iex> poly = %Geo.Polygon{coordinates: [[{0,0},{10,0},{10,10},{0,10},{0,0}]]}
iex> Meridian.Geometry.contains?(poly, %Geo.Point{coordinates: {5, 5}})
true
iex> Meridian.Geometry.contains?(poly, %Geo.Point{coordinates: {15, 5}})
false

@spec envelope(Yog.Graph.t()) :: Geo.Polygon.t() | nil

Computes the bounding envelope of all node geometries in a graph.

Returns a %Geo.Polygon{} representing the bounding box, or nil if no geometries are present.

Examples

iex> g = Meridian.Graph.new()
iex> g = g
...>   |> Meridian.Graph.add_node(:a, %{geometry: %Geo.Point{coordinates: {0.0, 0.0}}})
...>   |> Meridian.Graph.add_node(:b, %{geometry: %Geo.Point{coordinates: {2.0, 3.0}}})
iex> %Geo.Polygon{} = Meridian.Geometry.envelope(Meridian.Graph.to_yog(g))

@spec euclidean(Geo.Point.t(), Geo.Point.t()) :: float()

Euclidean distance between two points.

Examples

iex> a = %Geo.Point{coordinates: {0.0, 0.0}}
iex> b = %Geo.Point{coordinates: {3.0, 4.0}}
iex> Meridian.Geometry.euclidean(a, b)
5.0

@spec geo_length(Geo.LineString.t()) :: float()

Approximate length of a Geo.LineString in meters using the haversine formula.

Sums the great-circle distance of each segment.

Examples

iex> line = %Geo.LineString{coordinates: [{0.0, 0.0}, {0.0, 1.0}]}
iex> len = Meridian.Geometry.geo_length(line)
iex> len > 110_000 and len < 112_000
true