geosquare / geojson-equality Goto Github PK

The way GeojsonEquality check handles precision can result in incorrect results. The following example illustrates the problem:

const point1 = {"type": "Point", "coordinates": [100.55719328, 23.0365925]}
const point2 = {"type": "Point", "coordinates": [100.55719327926636, 23.03659249995325]}

const eq1 = new GeojsonEquality({ precision: 7});
const eq2 = new GeojsonEquality({ precision: 6});
eq1.compare(point1, point2)   // returns true
eq2.compare(point1, point2)   // returns false !

This is incorrect. If two points are equal to a precision of 7, then by definition they must be equal to a precision of 6 as well. The problem here arises from the use of toFixed to round the coordinates. The problem is that this introduces rounding errors that then cause the equality check to fail.

I think a better way to check that values are within the required precision is something like:

Math.abs(a - b) < (10**-6) // returns true, as expected
Math.abs(a - b) < (10**-7) // returns true, as expected

Very happy to make a PR if you agree that this is a preferable approach.

Add support for bbox comparison in geojson for type "Feature".

Any chance to support esm and not commonjs?