arrays - Position compression using relative coordinates in Javascript -

goodafternoon. have set of coordinates

[ [ 52.52132, 4.52342 ], [ 52.52144, 4.52352 ], [ 52.52154, 4.52354 ], [ 52.52166, 4.52376 ] ] 

how can transform first position (the first 2 coordinates) become base. , following positions relative distances base?

so, pseudo example:

this

[ [ 52.52132, 4.52342 ], [ 52.52144, 4.52352 ], [ 52.52154, 4.52354 ], [ 52.52166, 4.52376 ] ] 

would become this:

[ [ 52.52132, 4.52342 ], [ 0.4123, 0.1232 ], [ 0.1232, 0.5523 ], [ 0.1233, 0.1232 ] ] 

where first part [ 52.52132, 4.52342 ] starting point. , other coordinates relative previous one.

is after..

i'm not sure how getting 0.4123, 0.1232, 52.52144 - 52.52132 = 0.00012

also if after simple latlng compression / decompression system. i've done little 1 here, it's simple compressor,.. after works out different. multiple loops of multiplying diffs 1 10 100 1000, etc. , keeps track of return smallest stringified result. in store multiplier first element.

eg. example compress -> 5,52.52132,4.52342,12,10,10,2,12,22

the 5 equal difference mutliplier of 100000, use work out divide difference by. adding zlib compress more.

var g = [ [ 52.52132, 4.52342 ], [ 52.52144, 4.52352 ], [ 52.52154, 4.52354 ], [ 52.52166, 4.52376 ] ],      n = g.slice(0,1);    function compresslatlng(g) {    var smallest = null, r, mul;    if (!g.length) return '';    (var l = 1; l < 6; l ++) {      mul = math.pow(10, l);      r = [l,g[0][0],g[0][1]];      (var k = 1; k < g.length; k ++) {        r.push(          ((g[k][0] - g[k-1][0])*mul).tofixed(5)*1,          ((g[k][1] - g[k-1][1])*mul).tofixed(5)*1        );      }      var j = r.join(',');      if (!smallest) smallest = j;      else if (j.length < smallest.length) smallest = j;    }      return smallest;  }    function uncompresslatlng(s) {    var r = s.split(',');    if (!r.length) return [];    var mul = math.pow(10,r[0]);    var j = [[r[1]*1, r[2]*1]];    var last = j[0];    (var l = 3; l < r.length; l += 2) {      var t = [        (last[0] + r[l] / mul).tofixed(5)*1,        (last[1] + r[l+1] / mul).tofixed(5)*1      ];      j.push(t);      last = t;    }    return j;  }      (var l = 1; l < g.length; l ++) {    n.push([      (g[l][0] - g[l-1][0]).tofixed(5)*1,      (g[l][1] - g[l-1][1]).tofixed(5)*1    ]);  }    console.log('o:original s:simple c:compressed u:uncompressed');  console.log('o: ' + json.stringify(g));  console.log('s: ' + json.stringify(n));  var compressed = compresslatlng(g);  console.log('c: ' + compressed);  console.log('u: ' + json.stringify(uncompresslatlng(compressed)));