Function: isobands()
ts
function isobands(field, levels?): IsobandPolygon[];Defined in: charts/fields.ts:63
Filled contour bands (matplotlib's contourf).
Each grid cell is split into four triangles around its centre before clipping, which is what removes the saddle ambiguity plain marching squares has — a triangle's linear interpolant cannot produce two disjoint regions.
A cell only needs that subdivision when it actually straddles a level, which most cells do not — the interior of a band is the bulk of any field. Runs of uniform cells along a row merge into one rectangle, so a smooth field emits a few wide bars per band instead of a polygon per cell. That is where the polygon count — and the triangulation and upload behind it — mostly goes.
Parameters
| Parameter | Type | Default value |
|---|---|---|
field | ScalarField | undefined |
levels | number | number[] | 8 |