Notes on handling elevation with Geojson

README.md

There are a couple of approaches to encoding elevation in geojson.

1. The value for a feature's coordinates key should an array of numbers, which are ordered easting, northing and (optionally) altitude. The array represents a position.
2. Alternatively, you can make the elevation value one of the feature's properties.

Both approaches are demonstrated below.

{
  "type": "Feature",
  "properties": {
    "name": "Mount Ruapehu",
    "elevation_m": 2797
  },
  "geometry": {
    "type": "Point",
    "coordinates": [
      175.55890560150146,
      -39.28834275351452,
      2797
    ]
  }
}

elevations.geojson

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "name": "Mount Ruapehu",
        "elevation_m": 2797
      },
      "geometry": {
        "type": "Point",
        "coordinates": [
          175.55890560150146,
          -39.28834275351452,
          2797
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "name": "Mount Ngauruhoe",
        "elevation_m": 2291
      },
      "geometry": {
        "type": "Point",
        "coordinates": [
          175.63284873962402,
          -39.1561465200944,
          2291
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "name": "Mount Tongariro",
        "elevation_m": 1978
      },
      "geometry": {
        "type": "Point",
        "coordinates": [
          175.6347370147705,
          -39.13152499104364,
          1978
        ]
      }
    }
  ]
}