Massive polygon throws an error from turf

[derrickpelletier]

Error: Each LinearRing of a Polygon must have 4 or more Positions.

When attempting to run the streaming example on the massive polygon.

[phatal]

same problem (

[derrickpelletier]

@phatal This repo hasn't been updated in a while, but you might try changing the dependency for turf to some of the more recent versions to see if they've corrected what might have caused the issues.

[phatal]

@derrickpelletier Actually I found solution :) stringify coordinates array before sending them from parsed *.geojson. That helped me.

[derrickpelletier]

Oh interesting, so the coordinates array is actually a string? When i try that with the examples/streaming.js file, and change the massive poly to massive = JSON.stringify(massive) i continue to get the same error.

[phatal]

@derrickpelletier Code that almost worked for me. At least it's accept my coordinates array. Look strange why we need stringify and then parse it again, but it work )) `var hasher = require('../index'), async = require('async'), through2 = require('through2'), ngeohash = require('ngeohash'), queue = require('queue-async'), fs = require('fs');

var currDir = process.cwd(); var inputDir = 'input'; var outputDir = 'output'; var fileName = 'world_level2_test.geojson'; var inputFilePath = currDir+'/'+inputDir+'/'+fileName;

var worldData = JSON.parse(fs.readFileSync(inputFilePath));

var n = worldData.features.length; var i = 0; var q = queue();

function convertMe(polygonArray){ var toWrite = '';

var polygon = JSON.parse(polygonArray);
var isFirst = true;
var printFeature = function (name, poly) {
  var out = {
    "type": "Feature",
    "properties": {
      'name': name,
    },
    "geometry": {
      "type": "Polygon",
      "coordinates": poly
    }
  };
  out = JSON.stringify(out);
  if(!isFirst) {
    out = ',' + out
  }
  isFirst = false;

  toWrite = toWrite + out;
}
toWrite = toWrite + '{"type": "FeatureCollection","features": [';
async.mapSeries([polygon], function (poly, cb) {

  var options = {
    coords: poly,
    precision: 6,
    rowMode: true,
    hashMode: 'extent',
    //threshold: 0.2
  };
  printFeature('shape', poly);
  var rowStream = hasher.stream(options),
    a = 0;

  rowStream
    .on('end', cb)
    .pipe(through2.obj(function (arr, enc, callback) {
      for(var i = 0; i < arr.length; i++) {
        var bb = ngeohash.decode_bbox(arr[i]);
        printFeature(arr[i], [
              [
                [bb[1], bb[2]],
                [bb[3], bb[2]],
                [bb[3], bb[0]],
                [bb[1], bb[0]],
                [bb[1], bb[2]]
              ]]);
      }
      callback();
      toWrite = toWrite + ']}';

    }));
}, function () {

  return toWrite;
});

};

worldData.features.forEach(function(feature){ q.defer(function(done){ var dataToConvert = JSON.stringify(feature.geometry.coordinates); console.log('Start'); console.log(convertMe(dataToConvert)); fs.writeFileSync(currDir+'/'+outputDir+'/'+'cell_'+i+'.s2', dataToWrite); i++; done(); console.log('Finish');
}); });`

But I have problem with asynchronous call in foreach =/ convertMe(dataToConvert) always return undefined, i know that asynchronous call, but dunno how to fix it to get it work.

[ararog]

I used multiPolygon and my polygon worked as expected.