Union computation failure

[manubb]

Using this set of polygons:

const set = [
	[
		[
			[541.0184069121032,-143.03237832156836],
			[538.8976288020026,-123.35535843900269],
			[537.8321066666686,-122.80116457495023],
			[536.8855437278494,-123.35069884911623],
			[538.8870716306947,-141.92129053535714],
			[540.0894577777653,-143.74533713285928]
		]
	],
	[
		[
			[540.7750579535648,-143.21914611949745],
			[540.0894577777653,-143.74533713285928],
			[539.662835668487,-144.64976710575652],
			[539.7288124662978,-144.67804017205043],
			[540.3113546885238,-144.90328991644918],
			[540.6719999999914,-143.97058687725803]
		]
	],
	[
		[
			[557.6320465703087,-141.3264757967004],
			[540.8116376490731,-142.95242750964428],
			[540.6719999999914,-143.97058687725803],
			[541.2045466710015,-144.9237692724459],
			[557.0433079860503,-143.3927089271412],
			[558.1482666666561,-142.28123640691047]
		]
	],
	[
		[
			[532.7840286412132,-156.0428207910487],
			[541.2045466710015,-144.9237692724459],
			[540.6719999999914,-143.97058687725803],
			[539.8748041328679,-143.3668661227355],
			[531.3858333791956,-154.5763074915546],
			[531.7154133333242,-155.79750159024843]
		]
	],
	[
		[
			[538.8870716306947,-141.92129053535714],
			[513.8619652247359,-127.83939169834923],
			[511.28554246236985,-128.25021939873648],
			[511.7826658464412,-128.96424912185236],
			[539.5990569575308,-144.61683414118076],
			[539.662835668487,-144.64976710575652],
			[540.0894577777653,-143.74533713285928]
		]
	]
];

calling:

polygonClipping.union(set[0], set[1], set[2], set[3], set[4]);

fails with:

Error: Unable to complete output ring starting at [539.8561832464202, -143.39145446694468].
Last matching segment found ends at  [539.8561832464202, -143.39145446694462].

The polygons look like:

[mfogel]

Great, thanks for the bug report. I've reproduced the error on my side and will find time to do a deep dive into this case in the next few days.

Slightly simpler case that still generates the error:

> polygonClipping.union(set[0], set[3], set[4]);
Error: Unable to complete output ring starting at [539.8561832464202, -143.39145446694468]. Last matching segment found ends at  [539.8561832464202, -143.39145446694462].

[mfogel]

Simplified geometry that still reproduces the error - take union of these three polygons:

{
  "type": "MultiPolygon",
  "coordinates": [
    [[[541, -42], [538.88, -41.92], [540.09, -43.74]]],
    [[[538, -44], [538.88, -41.92], [540.09, -43.74]]],
    [[[541, -44], [539.87, -43.37], [538.73, -44.88]]]
  ]
}

[mfogel]

@manubb this should be fixed on master now if you want to give it a try. Running the original polygons you posted through I now get a result of:

Thanks for the bug report!