Crate contour

Computes isorings and contour polygons by applying marching squares to a rectangular array of numeric values.

Outputs ring coordinates (using contour_rings) or polygons contours (using ContourBuilder) as a Vec of GeoJSON Feature.

This is a port of d3-contour.

Example:

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:

[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
   }]

Structs

ContourBuilder

Contours generator to be used on a rectangular Slice of values to get a Vec of Features of MultiPolygon (use contour_rings internally).

Functions

contour_rings

Computes isoring for the given Slice of values according to the threshold value (the inside of the isoring is the surface where input values are greater than or equal to the given threshold value).