GeoMeasure

A collection of functions calculating different properties of Geo structs.

Currently, this project supports only the following geometries:

Point
PointM
PointZ
PointZM
LineString
Polygon

Currently, the following properties can be calculated for the supported Geo structs:

Area
Bounding box
Centroid
Distance (between two coordinate pairs or Geo.Point(M) structs)
Extent
Perimeter

For each geometry, only the properties that have meaning for the given geometry are implemented. This results in the following implementation table, where ✅ means supported, and ❌ means unsupported property:

Geometry	Area	Bounding box	Centroid	Distance	Extent	Perimeter
Point	❌	✅	✅	✅	❌	❌
PointM	❌	✅	✅	✅	❌	❌
PointZ	❌	✅	✅	✅	❌	❌
PointZM	❌	✅	✅	✅	❌	❌
LineString	❌	✅	✅	❌	✅	❌
Polygon	✅	✅	✅	❌	✅	✅

Note: If you would like to make in-memory calculations to determine the relationship between two Geo structs, please check out topo.

defp deps do
  [
    {:geomeasure, "~> 1.2.0"}
  ]
end

Examples

While each function can be called through their module, such as GeoMeasure.Area.calculate or GeoMeasure.Perimeter.calculate, it is encouraged to use delegates from the main GeoMeasure module, enabling shortened calls, such as GeoMeasure.area or GeoMeasure.perimeter. Thus, the following examples will only show the shorter, more convenient calls through GeoMeasure.

Area

iex(1)> GeoMeasure.area(%Geo.Polygon{coordinates: [[{0, 0}, {0, 2}, {2, 2}, {2, 0}, {0, 0}]]})
4.0

Bounding Box

iex(1)> GeoMeasure.bbox(%Geo.Point{coordinates: {1, 2}})
%Geo.Point{coordinates: {1, 2}, srid: nil, properties: %{}}

iex(2)> GeoMeasure.bbox(%Geo.PointM{coordinates: {1, 2, 5}})
%Geo.Point{coordinates: {1, 2}}

iex(3)> GeoMeasure.bbox(%Geo.PointZ{coordinates: {1, 2, 5}})
%Geo.PointZ{coordinates: {1, 2, 5}}

iex(4)> GeoMeasure.bbox(%Geo.PointZM{coordinates: {1, 2, 5, 8}})
%Geo.PointZ{coordinates: {1, 2, 5}}

iex(5)> GeoMeasure.bbox(%Geo.LineString{coordinates: [{1, 2}, {3, 4}]})
%Geo.Polygon{
  coordinates: [[{1, 2}, {1, 4}, {3, 4}, {3, 2}, {1, 2}]],
  srid: nil,
  properties: %{}
}

iex(6)> GeoMeasure.bbox(%Geo.Polygon{coordinates: [[{0, 0}, {0, 2}, {2, 2}, {2, 0}, {0, 0}]]})
%Geo.Polygon{
  coordinates: [[{0, 0}, {0, 2}, {2, 2}, {2, 0}, {0, 0}]],
  srid: nil,
  properties: %{}
}

Centroid

iex(1)> GeoMeasure.centroid(%Geo.Point{coordinates: {1, 2}})
%Geo.Point{coordinates: {1, 2}, srid: nil, properties: %{}}

iex(2)> GeoMeasure.centroid(%Geo.PointM{coordinates: {1, 2, 5}})
%Geo.Point{coordinates: {1, 2}}

iex(3)> GeoMeasure.centroid(%Geo.PointZ{coordinates: {1, 2, 5}})
%Geo.PointZ{coordinates: {1, 2, 5}}

iex(4)> GeoMeasure.centroid(%Geo.PointZM{coordinates: 1, 2, 5, 8})
%Geo.PointZ{coordinates: {1, 2, 5}}

iex(5)> GeoMeasure.centroid(%Geo.LineString{coordinates: [{1, 2}, {3, 4}]})
%Geo.Point{coordinates: {2.0, 3.0}, srid: nil, properties: %{}}

iex(6)> GeoMeasure.centroid(%Geo.Polygon{coordinates: [[{0, 0}, {0, 2}, {2, 2}, {2, 0}, {0, 0}]]})
%Geo.Point{coordinates: {1.0, 1.0}, srid: nil, properties: %{}}

Distance

iex(1)> GeoMeasure.distance({0, 0}, {5, 0})
5.0

iex(2)> GeoMeasure.distance({0, 0}, {3, 4})
5.0

iex(3)> GeoMeasure.distance({0, 0, 0}, {1, 1, 1})
1.7320508075688772

iex(4)> GeoMeasure.distance(%Geo.Point{coordinates: {0, 0}}, %Geo.Point{coordinates: {3, 4}})
5.0

iex(5)> GeoMeasure.distance(%Geo.PointM{coordinates: {0, 0, 5}}, %Geo.PointM{coordinates: {3, 4, 10}})
5.0

iex(6)> GeoMeasure.distance(%Geo.PointM{coordinates: {0, 0, 5}}, %Geo.Point{coordinates: {3, 4}})
5.0

iex(7)> GeoMeasure.distance(%Geo.PointZ{coordinates: {0, 0, 0}}, Geo.PointZ{coordinates: {1, 1, 1}})
1.7320508075688772

iex(8)> GeoMeasure.distance(%Geo.PointZM{coordinates: {0, 0, 0, 8}}, Geo.PointZM{coordinates: {1, 1, 1, 6}})
1.7320508075688772

iex(9)> GeoMeasure.distance(%Geo.PointZM{coordinates: {0, 0, 0, 8}}, %Geo.PointZ{coordinates: {1, 1, 1}})
1.7320508075688772

Extent

iex(1)> GeoMeasure.extent(%Geo.LineString{coordinates: [{1, 2}, {3, 4}]})
{1, 3, 2, 4}

iex(2)> GeoMeasure.extent(%Geo.Polygon{coordinates: [[{0, 0}, {0, 2}, {2, 2}, {2, 0}, {0, 0}]]})
{0, 2, 0, 2}

Perimeter

iex(1)> GeoMeasure.perimeter(%Geo.Polygon{coordinates: [[{0, 0}, {0, 2}, {2, 2}, {2, 0}, {0, 0}]]})
8.0

Copyright and License

Released under the MIT License, which can be found in the repository's LICENSE file.