Turf: Incorrectly getting `null` from `turf.intersect`

[dschep]

I'm trying to use turf to generate intersections of some polygons but it randomly seems to not work. For example, the polygons in this gist clearly intersect, but turf.intersect returns null

> const turf = require('@turf/turf');
> const data = require('./data.json');
> turf.intersect(data.features[0], data.features[1])
null

https://gist.github.com/dschep/92bc5f308b8506a774ecc9482795ccdf

[plarner30]

Can replicate starting with version 5.04

[dschep]

Oh, so it's a newish bug. That's really interesting. Bc turf is so modular, I tried to use @turf/intersect@<5.0.4 but then got some odd outputs too. Since I'm actually not generally using modular turf in this script, I do this and it seems to work:

const turf = require('@turf/turf') # ^5.1.6 in package.json
const intersect = require('@turf/intersect') # <5.0.4 in package.json
let intersection = turf.intersect(poly1, poly2) || intersect(poly1, poly2)

[tibetty]

The turf.intersect function is just a thin && buggy layer of user-friendly encapsulation of martinez-polygon-clipping, please consider using it directly. I encountered the same issue and got it resolved with that package.

[dschep]

Thanks for the pointer @tibetty, I'll check that out.

[Type1J]

I had to use martinez-polygon-clipping directly as well. Can this be updated in turf?

[MajorDOOM]

I have the same issue, function turf.intersect returning null with this code :
turf.intersect({"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[2.269577978076996,48.71995650497067],[2.3007435825130793,48.737428870414234],[2.300675792911607,48.73748135853885],[2.269577978076996,48.71995650497067]]]}},{"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[2.2684729099273686,48.724622826193],[2.3092314581589743,48.72685694535847],[2.3092211749806038,48.7269373823835],[2.2684729099273686,48.724622826193]]]}})

But unfortunately the 2 polygons (in blue below) when drawn on a map seem intersect :

https://codepen.io/MajorDOOM/pen/dyPmELz

[wlievens]

I have a similar case of polygons reporting a null intersection.

https://jsfiddle.net/wlievens/tmj8Ln32/13

var p1 = {"type":"Polygon","coordinates":[[
[41.85587797331998,85.05112877980659],
[37.397392190303705,68.44639338124588],
[21.4340365960655,54.312614791502085],
[8.310282594978935e-9,67.92046278551715],
[8.310282594978935e-9,85.05112877980659],
[41.85587797331998,85.05112877980659]
]]};

var p2 = {"type":"Polygon","coordinates":[[
[10.41346496136495,85.05112778577897],
[10.413464623816678,85.05112794274982],
[10.413464666297507,85.05112810235666],
[10.413465087004509,85.05112825782558],
[10.41346586808238,85.05112840255832],
[10.413466976381255,85.05112853041223],
[10.413468364863629,85.05112863596105],
[10.413469974600678,85.05112871472518],
[10.413471737273266,85.05112876336175],
[10.413473578071496,85.05112877980659],
[79.58652642192847,85.05112877980659],
[79.5865282627267,85.05112876336175],
[79.58653002539928,85.05112871472518],
[79.58653163513635,85.05112863596105],
[79.58653302361871,85.05112853041223],
[79.58653413191759,85.05112840255832],
[79.58653491299546,85.05112825782558],
[79.58653533370246,85.05112810235666],
[79.58653537618329,85.05112794274982],
[79.58653503863503,85.05112778577897],
[45.000008616706545,52.95134261468802],
[45.00000795060929,52.95134162544201],
[45.00000697518646,52.95134073421229],
[45.00000572838777,52.951339975672965],
[45.00000425872103,52.951339379335685],
[45.000002623364914,52.95133896840149],
[45.000000885944466,52.95133875885815],
[44.99999911405554,52.95133875885815],
[44.999997376635086,52.95133896840149],
[44.99999574127899,52.951339379335685],
[44.99999427161223,52.951339975672965],
[44.99999302481355,52.95134073421229],
[44.99999204939071,52.95134162544201],
[44.999991383293455,52.95134261468802],
[10.41346496136495,85.05112778577897]
]]};

console.log(turf.intersect(p1, p2));