script to decode a polyline (monkseaton to south shields) and check for a station (palmersville) on that line

index.js

let polyline = require('@mapbox/polyline');
let points = polyline.decode('si}nI~x{G[vAoAu@_ChKs@pDg@jDW~CMtBIrD?tBJzDp@|GVbBv@bEzGbZrFzU~AfHxApGlAxGhAxH|@fIj@vGXtFX|HVnMjBteAZxPE@TfKZ|HdAxMdBdR\\lCt@hDjA~CfBrCfAjBv@~Az@~B`AvCv@~B`GlQ|EtN|CvJzHhUrErNfJpX~AzEjBpEfBtEL^DGtD`LpBbGzAxDx@`Br@fAtEdHp@nA~@`Cz@`Dp@xDRxBPzBj@bEbAzEpBlH`CjK~BzKxEzTbDfOdCbMxCvN~@fEh@|ChAnFxAtFfD~Kr@~Bz@jDdBrHrAxI`AnJd@~HPdFL`KChGSvImAlUwAzWo@bLIfC?fA@fANlE^hDn@lDx@vCbA`CtAzBrAzAn@h@dAj@TJhA\\|CfA`J`DdEpArHfCrFlB`Bl@@IrEvAtCl@xCRnBAlBUpAQhAYjBo@nB_A|ByAtBgBtDeDpDsClCaBtD_BbA_@vBk@~KyBpGsAtFmAx@Gd@Ah@B|B`@|A\\~@p@|@fAzAbCpAdCfBtDbE`LfDhI~@pB|A`Cn@r@^Z|@\\hA@dBOxEw@hGu@f@AjANhBp@vAt@rHpEhI~Er@h@t@`@t@XbANfCZ~@Cn@UbAy@xAuBxBiDnLuQZu@\\eBnHul@FDxI}r@pAmLbAiKj@iDxAoFjFaPp@mCh@wCjB_LpBoMbE_XZwBjAeGz@cEn@yDdAgHQKFa@bCoPt@mGf@oFn@_KZ_I\\gY?oCMoD_@yHOqB{@gUwA}_@c@}Pc@gM]uWOcHIcB[}Bq@cDi@wA}@aB}@eAo@i@_Ac@y@SgAKmBGiBUaEy@{UkE_KiBeJiBsCm@_D_@cGkA}Cy@wB{@oCsAyBmAwCwBgC}BwD_EyBkC_CiDiAgBgAiBaD}FuAuCaBsDm@wAsBuFmAyD_B{Fk@cCgAkFwD_S{DySy@sG]kESeEI{E?mEHkDHkDPkCj@{Fl@}DhA_GbAwD~@sCpDyKr@oC`@qBf@iDv@iIhDub@hBcUrCc^tAwP`AqK^kDn@}Dh@iDh@oDtEgYdNg{@x@mFRmCBsBGwBUgCO}@{@_Dy@eBcBoBaOwKeCgBiBsAo@q@sG{GyCaDyBiB}FwEkEoDwDaD}EqCuAgAeAmAgAgBcBuDq@wAgA_BwAsA}Aq@eASaAC{BEcADgBAgBRsA^oCbAeCRaB@qLLgF^cDJoESyBAyCTwAb@oAj@OHAE');

let palmersville_2_lat = 55.023781;
let palmersville_2_lng = -1.541083;
let palmersville_1_lat = 55.023728;
let palmersville_1_lng = -1.54102;

let distance_from_palmersville_p1 = [];
let distance_from_palmersville_p2 = [];

for (var i = 0; i < points.length; i++) {
	point = points[i];
	let lat = point[0];
	let lng = point[1];
	distance_from_palmersville_p1[i] = Number(Math.hypot(lat - palmersville_1_lat,lng-palmersville_1_lng));
	//console.log('at '+i+' distamce to p1 was '+distance_from_palmersville_p1[i]);
	distance_from_palmersville_p2[i] = Number(Math.hypot(lat - palmersville_2_lat,lng-palmersville_2_lng));
	//console.log('at '+i+' distamce to p2 was '+distance_from_palmersville_p2[i]);
	
	if (lat==palmersville_1_lat && lng==palmersville_1_lng) {
		console.log("found palmersville platform 1 as position no. "+i);
	}
	if (lat==palmersville_2_lat && lng==palmersville_2_lng) {
		console.log("found palmersville platform 2 as position no. "+i);
	}
}




let min_dist_from_palmersville_p1 = Math.min(...distance_from_palmersville_p1);
console.log('min dist to palmersville p1 was '+min_dist_from_palmersville_p1);
let index_of_min_dist_from_palmersville_p1 = distance_from_palmersville_p1.indexOf(min_dist_from_palmersville_p1);
let min_dist_from_palmersville_p2 = Math.min(...distance_from_palmersville_p2);
console.log('min dist to palmersville p2 was '+min_dist_from_palmersville_p2);
let index_of_min_dist_from_palmersville_p2 = distance_from_palmersville_p2.indexOf(min_dist_from_palmersville_p2);

console.log('the closest point to palmersville platform 1 was the '+index_of_min_dist_from_palmersville_p1+'th position which is '+points[index_of_min_dist_from_palmersville_p1]);

console.log('the closest point to palmersville platform 2 was the '+index_of_min_dist_from_palmersville_p2+'th position which is '+points[index_of_min_dist_from_palmersville_p2]);