Geo v3.1.0 Geo View Source
A collection of GIS functions. Handles conversions to and from WKT, WKB, and GeoJSON for the following geometries:
- Point
- PointZ
- LineString
- Polygon
- MultiPoint
- MulitLineString
- MultiPolygon
- GeometryCollection
Examples
- Encode and decode WKT and EWKT
iex(1)> point = Geo.WKT.decode("POINT(30 -90)")
%Geo.Point{ coordinates: {30, -90}, srid: nil}
iex(2)> Geo.WKT.encode(point)
"POINT(30 -90)"
iex(3)> point = Geo.WKT.decode("SRID=4326;POINT(30 -90)")
%Geo.Point{coordinates: {30, -90}, srid: 4326}
- Encode and decode WKB and EWKB
iex(1)> point = Geo.WKB.decode("0101000000000000000000F03F000000000000F03F")
%Geo.Point{ coordinates: {1.0, 1.0}, srid: nil }
iex(2)> Geo.WKB.encode(point)
"00000000013FF00000000000003FF0000000000000"
iex(3)> point = Geo.WKB.decode("0101000020E61000009EFB613A637B4240CF2C0950D3735EC0")
%Geo.Point{ coordinates: {36.9639657, -121.8097725}, srid: 4326 }
iex(4)> Geo.WKB.encode(point)
"0020000001000010E640427B633A61FB9EC05E73D350092CCF"
Encode and decode GeoJSON
Geo only encodes and decodes maps shaped as GeoJSON. JSON encoding and decoding must be done before and after.
#Examples using Poison as the JSON parser
iex(1)> Geo.JSON.encode(point)
%{ "type" => "Point", "coordinates" => [100.0, 0.0] }
iex(2)> point = Poison.decode!("{ "type": "Point", "coordinates": [100.0, 0.0] }") |> Geo.JSON.decode
%Geo.Point{ coordinates: {100.0, 0.0}, srid: nil }
iex(3)> Geo.JSON.encode(point) |> Poison.encode!
"{"type":"Point","coordinates":[100.0,0.0]}"
Link to this section Summary
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endian()
View Source
endian()
View Source
endian() :: :ndr | :xdr
endian() :: :ndr | :xdr
Link to this type
geometry()
View Source
geometry()
View Source
geometry() ::
Geo.Point.t()
| Geo.PointZ.t()
| Geo.PointM.t()
| Geo.PointZM.t()
| Geo.LineString.t()
| Geo.Polygon.t()
| Geo.MultiPoint.t()
| Geo.MultiLineString.t()
| Geo.MultiPolygon.t()
| Geo.GeometryCollection.t()
geometry() :: Geo.Point.t() | Geo.PointZ.t() | Geo.PointM.t() | Geo.PointZM.t() | Geo.LineString.t() | Geo.Polygon.t() | Geo.MultiPoint.t() | Geo.MultiLineString.t() | Geo.MultiPolygon.t() | Geo.GeometryCollection.t()