Swift GeoJson解析

问题描述

{
  "type": "Feature","geometry": {
    "type": "Point","coordinates": [
      126.9823439963945,37.56461982743129
    ]
  }
},{
  "type": "Feature","geometry": {
    "type": "Linestring","coordinates": [
      [
        126.9823439963945,37.56461982743129
      ],[
        126.98230789017299,37.564453179812105
      ],[
        126.98210513804034,37.563703265276516
      ],[
        126.98207180945346,37.56352550784786
      ],[
        126.9817857308457,37.56284502921221
      ],[
        126.98166907678578,37.562633941789535
      ],[
        126.98157186492477,37.56247284870586
      ],[
        126.98128300624569,37.56205345097403
      ],[
        126.98124689891416,37.56200067907546
      ]
    ],"traffic": [0,8,4,12]
  }}

这就是我得到的。而且我不知道解析关键的“坐标”。此类型取决于几何类型。如果类型为“ Point”，则类型变为[String]。如果类型为“ Linestring”，则类型变为[[String]]。我该怎么解决？

解决方法

您可以使用以下可可豆荚：CodableGeoJSON。

它已为您编写了Codable结构。您似乎在这里具有一个未知几何的特征，因此可以执行以下操作：

let geoJSON = try JSONDecoder().decode(GeoJSON.self,from: geoJSONData)
guard case .feature(let feature) = geoJSON else {
    // the GeoJSON does not contain a feature!
}

// handle each kind of geometry...
switch feature.geometry {
case .point(let coordinates): // coordinates is a GeoJSONPosition
    // ...
case .multiPoint(let coordinates): // coordinates is a [GeoJSONPosition]
    // ...
case .lineString(let coordinates): // coordinates is a [GeoJSONPosition]
    // ...
case .multiLineString(let coordinates): // coordinates is a [[GeoJSONPosition]]
    // ...
case .polygon(let coordinates): // coordinates is a [[GeoJSONPosition]]
    // ...
case .multiPolygon(let coordinates): // coordinates is a [[[GeoJSONPosition]]]
    // ...
case .geometryCollection(let geometries):
    // ...
}

如果您不只是为此目的而使用库，请查看其源代码并尝试从中学习，特别是GeoJSON.swift。

codable json parsing