GeometryBasics.jl
Basic geometry types.
This package aims to offer a standard set of geometry types that easily work with metadata, query frameworks on geometries and different memory layouts. The aim is to create a solid basis for graphics/plotting, finite element analysis, geo applications, and general geometry manipulations - while offering a Julian API that still allows performant C-interop.
This package is a replacement for the discontinued GeometryTypes.
Quick start
Create some points:
julia> using GeometryBasics
julia> p1 = Point(3, 1)
2-element Point2{Int64} with indices SOneTo(2): 3 1
julia> p2 = Point(1, 3);
julia> p3 = Point(4, 4);
Geometries can carry metadata:
julia> poi = meta(p1, city="Abuja", rainfall=1221.2)
2-element PointMeta{2, Int64, Point2{Int64}, (:city, :rainfall), Tuple{String, Float64}} with indices SOneTo(2): 3 1
Metadata is stored in a NamedTuple and can be retrieved as such:
julia> meta(poi)
(city = "Abuja", rainfall = 1221.2)
Specific metadata attributes can be directly retrieved:
julia> poi.rainfall
1221.2
To remove the metadata and keep only the geometry, use metafree
:
julia> metafree(poi)
2-element Point2{Int64} with indices SOneTo(2): 3 1
Geometries have predefined metatypes:
julia> multipoi = MultiPointMeta([p1], city="Abuja", rainfall=1221.2)
1-element MultiPointMeta{Point2{Int64}, MultiPoint{2, Int64, Point2{Int64}, Vector{Point2{Int64}}}, (:city, :rainfall), Tuple{String, Float64}}: [3, 1]
Connect the points with lines:
julia> l1 = Line(p1, p2)
Line([3, 1] => [1, 3])
julia> l2 = Line(p2, p3);
Connect the lines in a linestring:
julia> LineString([l1, l2])
2-element LineString{2, Int64, Point2{Int64}, Vector{Line{2, Int64}}}: Line([3, 1] => [1, 3]) Line([1, 3] => [4, 4])
Linestrings can also be constructed directly from points:
julia> LineString([p1, p2, p3])
2-element LineString{2, Int64, Point2{Int64}, Base.ReinterpretArray{Line{2, Int64}, 1, Tuple{Point2{Int64}, Point2{Int64}}, TupleView{Tuple{Point2{Int64}, Point2{Int64}}, 2, 1, Vector{Point2{Int64}}}, false}}: Line([3, 1] => [1, 3]) Line([1, 3] => [4, 4])
The same goes for polygons:
julia> Polygon(Point{2, Int}[(3, 1), (4, 4), (2, 4), (1, 2), (3, 1)])
Polygon{2, Int64, Point2{Int64}, LineString{2, Int64, Point2{Int64}, Base.ReinterpretArray{Line{2, Int64}, 1, Tuple{Point2{Int64}, Point2{Int64}}, TupleView{Tuple{Point2{Int64}, Point2{Int64}}, 2, 1, Vector{Point2{Int64}}}, false}}, Vector{LineString{2, Int64, Point2{Int64}, Base.ReinterpretArray{Line{2, Int64}, 1, Tuple{Point2{Int64}, Point2{Int64}}, TupleView{Tuple{Point2{Int64}, Point2{Int64}}, 2, 1, Vector{Point2{Int64}}}, false}}}}(Line{2, Int64}[Line([3, 1] => [4, 4]), Line([4, 4] => [2, 4]), Line([2, 4] => [1, 2]), Line([1, 2] => [3, 1])], LineString{2, Int64, Point2{Int64}, Base.ReinterpretArray{Line{2, Int64}, 1, Tuple{Point2{Int64}, Point2{Int64}}, TupleView{Tuple{Point2{Int64}, Point2{Int64}}, 2, 1, Vector{Point2{Int64}}}, false}}[])
Create a rectangle placed at the origin with unit width and height:
julia> rect = Rect(Vec(0.0, 0.0), Vec(1.0, 1.0))
Rect2{Float64}([0.0, 0.0], [1.0, 1.0])
Decompose the rectangle into two triangular faces:
julia> rect_faces = decompose(TriangleFace{Int}, rect)
2-element Vector{TriangleFace{Int64}}: TriangleFace(1, 2, 4) TriangleFace(1, 4, 3)
Decompose the rectangle into four vertices:
julia> rect_vertices = decompose(Point{2, Float64}, rect)
4-element Vector{Point2{Float64}}: [0.0, 0.0] [1.0, 0.0] [0.0, 1.0] [1.0, 1.0]
Combine the vertices and faces into a triangle mesh:
julia> mesh = Mesh(rect_vertices, rect_faces)
Mesh{2, Float64, Triangle}: Triangle([0.0, 0.0], [1.0, 0.0], [1.0, 1.0]) Triangle([0.0, 0.0], [1.0, 1.0], [0.0, 1.0])
Use GeometryBasics.mesh
to get a mesh directly from a geometry:
julia> mesh = GeometryBasics.mesh(rect)
Mesh{2, Float64, Triangle}: Triangle([0.0, 0.0], [1.0, 0.0], [1.0, 1.0]) Triangle([0.0, 0.0], [1.0, 1.0], [0.0, 1.0])