Accuracy issue with `nearestPoints` method

[chamikabm]

I have a line string as follows, consisting of a few points (longitude/latitude) coordinates in Paris. I tried to find the closest snapped point on the given line and from a give-point

line_string = [
			[
				145.0296835,
				-37.8089915
			],
			[
				145.0297712,
				-37.809002
			],
			[
				145.0298903,
				-37.8090163
			],
			[
				145.0303226,
				-37.8090682
			],
			[
				145.0304063,
				-37.8090783
			],
			[
				145.0313321,
				-37.8091894
			],
			[
				145.0322665,
				-37.8093016
			],
			[
				145.032952,
				-37.8093839
			],
			[
				145.033411,
				-37.809439
			],
			[
				145.0336591,
				-37.8094688
			],
			[
				145.0337068,
				-37.8094745
			],
			[
				145.0348664,
				-37.8096137
			],
			[
				145.0349955,
				-37.8096292
			]
		]

given_point = [
   145.03317585555192,
    -37.809289649922064
]

I’m using the LibGEOS library to do this as follows, but here’s the thing: visually, it looks like the point is snapping to the closest spot, but when I check with the intersect method using the same library, it turns out it’s not lining up with the provided line:

geos_point = LibGEOS.Point(given_point[1], given_point[2])
geos_line_string = LibGEOS.LineString(line_string)
point_on_linestring, point_on_point = LibGEOS.nearestPoints(geos_line_string, geos_point)
nearest_point = [ LibGEOS.getGeomX(point_on_linestring), LibGEOS.getGeomY(point_on_linestring) ]

But when I check the nearest point:

LibGEOS.intersects(nearest_point, geos_line_string) ==> False

Output of the above function gives as false, but If I input a point in the line_string separately, then it gives me true as follows:

point_in_the_line_string = LibGEOS.Point(145.0349955,-37.8096292)

LibGEOS.intersects(point_in_the_line_string, geos_line_string) ==> True

[jaakkor2]

As points are Float64, I would buffer the line a bit

LibGEOS.intersects(nearest_point, buffer(geos_line_string,1e-12))  # true

[chamikabm]

@jaakkor2 , Checking with a buffer would work, but what I wanna know, is what would be the most accurate way to create such a snapped point?