将JSON多边形坐标列表转换为GeoJSON格式的Long / Lat数组

Question

I am fetching data from a REST API which results in a list of datasets. Some of these datasets contain coordinates that I want to project on a map. In order to project the coordinates, I need to convert the JSON output to GeoJSON. While the conversion goes well for most parts of the data. I struggle with a long array containing x and y coordinates. It is 4+ points combined into polygons (5th endpoint = begin point is missing).

How can I convert this one array with 4+ XY coordinates to the right format while also adding the last one that should match the first point?

I thought about slicing the array into new ones for each point but this would result in too much work for polygons with over 20 points.

Example of the JSON:

"footprint": {
        "epsgId": 4326,
        "data": [
          [
            5.785569964298996,
            50.94215924789526,
            5.934953425435474,
            50.94154873163077,
            5.9341556116101595,
            50.87413533708443,
            5.784989651500041,
            50.87474468292546
          ]
        ],
      },

This is how it should look like after conversion into GeoJSON. I wrote this down myself, but I need a JavaScript code to do this automatically while looping through the results.

    {
      "type": "Feature",
      "properties": {
        "name": "name"
        "id" : "id"
      },
      "geometry": {
        "type": "Polygon",
        "coordinates": [
          [
            [5.785569964298996, 50.94215924789526],
            [5.934953425435474, 50.94154873163077],
            [5.9341556116101595, 50.87413533708443],
            [5.784989651500041, 50.87474468292546],
            [5.785569964298996, 50.94215924789526]
          ]
        ]
      }
    }

Answer 1

i think this function will do the work for you.

d = {"footprint": {
        "epsgId": 4326,
        "data": [
          [
            5.785569964298996,
            50.94215924789526,
            5.934953425435474,
            50.94154873163077,
            5.9341556116101595,
            50.87413533708443,
            5.784989651500041,
            50.87474468292546
          ]
        ],
      }
    }
console.log(d)

function convert(points)
{
  geojson = {
      "geometry": {
        "type": "Polygon",
        "coordinates": [
        ]
      }
  }
  var coordinates = new Array();
  for (var i = 0; i < points.length; i+=2) {
    coordinates.push([points[i],points[i+1]])
  }
  //closing the polygon
  coordinates.push([points[0],points[1]])
  // points need to be in zero index of coordinates array
  geojson.geometry.coordinates = new Array(coordinates);
  return geojson;
}

console.log(convert(d["footprint"]["data"][0]))