IsoLines does not trace lines, if multiple isolines are not closed.

[kerkovits]

Minimal non-working example:

MarchingSquaresJS.isoLines([[1,1,1,1],[0,0,0,0],[1,1,1,1]],0.5,{linearRing:false});

This should return two open isolines. Instead, the first isoline is connected, the second one is left in small segments without connecting them.

[MattiasJa]

I run into the same issue with isoLines in many small segments. This does not work well, or look well, when drawing paths in dashArray style... I did some experimenting with below function to combine arrays that seems to be connected. Works well in my case as a workaround :

function mergeConnectedPaths(pointArrays) {
    // Helper function to check if two arrays are connected
    function areConnected(array1, array2) {
        const end1 = array1[array1.length - 1];
        const start2 = array2[0];
        return end1[0] === start2[0] && end1[1] === start2[1];
    }
    const mergedPaths: number[][] = [];
    pointArrays.forEach((points) => {
        let merged = false;
        for (let i = 0; i < mergedPaths.length; i++) {
            const path = mergedPaths[i];

            if (areConnected(path, points)) {
                // Merge current points at the end of the existing path
                mergedPaths[i] = path.concat(points.slice(1));
                merged = true;
                break;
            } else if (areConnected(points, path)) {
                // Merge existing path at the end of the current points
                mergedPaths[i] = points.concat(path.slice(1));
                merged = true;
                break;
            }
        }
        if (!merged) {
            mergedPaths.push(points);
        }
    });
    return mergedPaths;
}