Understanding 'allsegs' in Contour Plots: A Guide to Polygon Segments

The 'allsegs' list contains all the polygon segments for all the levels. If we have contour lines, the length of 'allsegs' will be the same as the length of the 'levels' list. If we have filled contour regions, the length of 'allsegs' will be one less than the length of the 'levels' list.

Each level segment list, such as 'level0segs', contains a list of polygons. Each polygon is represented as a list of coordinate pairs, where each pair represents a vertex of the polygon.

Here is an example of how the 'level0segs' list should look like:

level0segs = [
    [[x0, y0], [x1, y1], ...],  # polygon0
    [[x2, y2], [x3, y3], ...],  # polygon1
    ...
]

Each 'polygon' list contains the coordinates of the vertices of the polygon. For example, 'polygon0' is represented by the list [[x0, y0], [x1, y1], ...], where [x0, y0], [x1, y1], etc. are the coordinate pairs of the polygon's vertices.