gistfile1.txt

var fs = require("fs");

fs.readFile("aurora-nowcast-map.txt","utf8",function(err,table){

  // Remove comment rows and empty rows
  var rows = table.split("\n").filter(function(row){
    return row.match(/^[0-9\s]+[0-9][0-9\s]+$/);
  }).map(function(row){
    // Map to space-delimited numbers
    return row.trim().split(/\s+/g).map(function(num){
      return +num;
    });
  });

  var featureCollection = {
    type: "FeatureCollection",
    features: []
  };

  // Calculate lat/lng bins
  rows.forEach(function(row,i){

    if (!cell) {
      return true;
    }

    var lat0 = -90 + (180 * i / 512),
        lat1 = lat0 + 1 / 512;

    row.forEach(function(cell,j){

      var lng0 = j / 1096 * 360,
          lng1 = lng0 + 1 / 1096;

      if (lng0 > 180) {
        lng0 = lng0 - 360;
      }

      if (lng1 > 180) {
        lng1 = lng1 - 360;
      }

      featureCollection.features.push({
        type: "Feature",
        properties: {
          probability: cell/100
        },
        geometry: {
          type: "Polygon",
          coordinates: [[
            [lng0,lat0],
            [lng0,lat1],
            [lng1,lat1],
            [lng1,lat0],
            [lng0,lat0]
          ]]
        }
      });

    });

  });

  fs.writeFile("probabilities.geo.json",JSON.stringify(featureCollection,null,"  "));

});