Create Mile Marker Features Along Race

README.md

This script caculates and creates a mile-marker for each mile within a race, in this case a 26 mile marathon.

Output example: https://gist.github.com/rgdonohue/dd78bfdb5f5da76596b2

createMarkers.js

var turf = require('turf');
var fs = require('fs');
var gp = require("geojson-precision");

fs.readFile('race_route.geojson', 'utf8', function(err,data){
  if(err) throw err;
  processData(JSON.parse(data))
});

function processData(data){

  var line = data.features[0];

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

  var i = 0;
  while(i <= 26){
    var along = turf.along(line,i,'miles');
    if(i == 0) {
      along.properties = { 'distance': 'start' };
    } else if(i == 26) {
      along.properties = { 'distance': 'finish' };
    } else {
      along.properties = { 'distance':'mile ' + i };
   }
    result.features.push(along);
    i++;
  }

  // trim ridiculous precison thnx to https://github.com/jczaplew/geojson-precision
  gp.parse(result,4);

  writeToFile(result);

}

function writeToFile(output){

  fs.writeFile('route_with_markers.json', JSON.stringify(output), function(err){
    if(err){
      return console.log(err);
    }
    console.log('success!')
  });

}

thumbnail.png