Computes isorings and contour polygons by applying marching squares to a rectangular array of numeric values.
Outputs ring coordinates or polygons contours as a Vec of GeoJSON Features.
Note : This is a port of d3-contour.
Add this to your Cargo.toml:
toml
[dependencies]
contour = "0.1.0"
and this to your crate root:
rust
extern crate contour;
The API exposes:
- a contour_rings function, which computes isorings coordinates for one threshold value (returns a Vec of rings coordinates).
- a ContourBuilder struct, which computes isorings coordinates for a Vec of threshold values and transform them in MultiPolygons (returns a Vec of GeoJSON Features).
rust
let c = ContourBuilder::new(10, 10, false); // x dim., y dim., smoothing
let res = c.contours(&vec![
0., 0., 0., 0., 0., 0., 0., 0., 0., 0.,
0., 0., 0., 0., 0., 0., 0., 0., 0., 0.,
0., 0., 0., 0., 0., 0., 0., 0., 0., 0.,
0., 0., 0., 1., 1., 1., 0., 0., 0., 0.,
0., 0., 0., 1., 1., 1., 0., 0., 0., 0.,
0., 0., 0., 1., 1., 1., 0., 0., 0., 0.,
0., 0., 0., 1., 1., 1., 0., 0., 0., 0.,
0., 0., 0., 1., 1., 1., 0., 0., 0., 0.,
0., 0., 0., 0., 0., 0., 0., 0., 0., 0.,
0., 0., 0., 0., 0., 0., 0., 0., 0., 0.
], &[0.5])?; // values, thresholds
Output:
rust
[Feature {
bbox: None,
geometry: Some(Geometry {
bbox: None,
value: MultiPolygon([[[
[6., 7.5], [6., 6.5], [6., 5.5], [6., 4.5],
[6., 3.5], [5.5, 3.], [4.5, 3.], [3.5, 3.],
[3., 3.5], [3., 4.5], [3., 5.5], [3., 6.5],
[3., 7.5], [3.5, 8.], [4.5, 8.], [5.5, 8.],
[6., 7.5]]]]),
foreign_members: None
}),
id: None,
properties: Some({"value": Number(0.5)}),
foreign_members: None
}]
Demo of this crate compiled to WebAssembly and used from JavaScript : wasmdemocontour.
Licensed under either of
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.