Issue on Converting Array of Coordinates to JSON

Question

I am trying to parse stored items of an Array which contains Coordinates of Drawing shapes on the map as into JSON Object/String:

var polys =[];

google.maps.event.addListener(drawingManager, 'polygoncomplete', function (polygon) {
  coordinates = (polygon.getPath().getArray());
  polys.push(coordinates);
});

I used this loop to convert the array to JSON data:

var info = [];
for(var i = 0; i < polys.length; i++){
    info.push({
        "type":"POL",
        "id": i,
        "geometry": polys[i]
    });
}

every thing fine but at result I am getting a "d" and "e" keys for the coordinates as:

[
   {
      "type":"POL",
      "id":0,
      "geometry":[
         {
            "d":49.26870064827097,
            "e":-122.89237976074219
         },
         {
            "d":49.25436113302859,
            "e":-122.9092025756836
         },
         {
            "d":49.24965507167121,
            "e":-122.88551330566406
         }
      ]
   },

Can you please let me know why this is happening? Since I am going to load the JSON data into MYSQL database, do you think this is a good approch to continue?

Dr.Molle · Accepted Answer · 2014-03-06 22:39:17Z

1

The objects with the e-and d-properties are google.maps.LatLng's, you must translate them into an array:

var info = [];
for(var i = 0; i < polys.length; i++){
    geometry=[];
    for(var j=0;j<polys[i].length;++j){
      geometry.push([polys[i][j].lat(),polys[i][j].lng()]);
    }
    info.push({
        "type":"POL",
        "id": i,
        "geometry": geometry
    });
}

To get the encoded path use this:

var info = [];
for(var i = 0; i < polys.length; i++){

    info.push({
        "type":"POL",
        "id": i,
        "geometry": google.maps.geometry.encoding.encodePath(polys[i])
    });
}

Note: you must load the geometry-library when you want to use the encoding, this library is not loaded by default

edited Mar 6, 2014 at 22:39

answered Mar 6, 2014 at 22:20

Dr.Molle

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8 Comments

Behrouz Hosseini K. Over a year ago

Thanks Dr.Molle, just have a quick question as well, I saw your post for saving data in a database and encoding the geometery hints. can you pleae also let me know how I can encode the gemoetry in my example?

Behrouz Hosseini K. Over a year ago

I am also getting this error Uncaught TypeError: Object [object Array] has no method 'lat'

Behrouz Hosseini K. Over a year ago

Thanks Dr. but how about my second question? do you think this is a good approch to load into database?

Behrouz Hosseini K. Over a year ago

Great Thaks a lot. Just one last question, if I want to read encoded json how can I do that?

Dr.Molle Over a year ago

added an example above. It's a good approach when you only want to store the data, because a encoded polyline takes less space. But when you want to be able to fetch data from the DB based on a geometric condition you can't use the encoded path. When you want to read the data you must decode the encoded path (also with the geometry-library, the method is google.maps.geometry.encoding.decodePath())

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