Extract data from GeoJSON - ios

Question

I am trying to retrieve the featureclass inside the GeoJSON below.
I have updated the GeoJSON below.
{
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"properties": {
"scalerank": 8,
"name": "Grill",
"website": "www.rocargo.com/SanNicolas.html",
"natlscale": 5,
"featureclass": "Meat"
},
"geometry": {
"type": "Point",
"coordinates": [-11.1086263, 59.1438153]
}
},
{
"type": "Feature",
"properties": {
"scalerank": 8,
"name": "Queen Vic",
"website": "www.rocargo.com/SanNicolas.html",
"natlscale": 5,
"featureclass": "Fish"
},
"geometry": {
"type": "Point",
"coordinates": [-11.1190539, 59.1498404]
}
},
{
"type": "Feature",
"properties": {
"scalerank": 8,
"name": "Josephines",
"website": "www.rocargo.com/SanNicolas.html",
"natlscale": 5,
"featureclass": "Bar"
},
"geometry": {
"type": "Point",
"coordinates": [-11.1145087,59.142496]
}
},
{
"type": "Feature",
"properties": {
"scalerank": 8,
"name": "Fall",
"website": "www.rocargo.com/SanNicolas.html",
"natlscale": 5,
"featureclass": "Port"
},
"geometry": {
"type": "Point",
"coordinates": [-11.1174109, 59.1402164]
}
}
]
}
The below function can pull all the information above.
func pleaseWork() {
let urlBar = Bundle.main.path(forResource: "bars", ofType: "geojson")!
if let jsonData = NSData(contentsOfFile: urlBar) {
do {
if let jsonResult: NSDictionary = try JSONSerialization.jsonObject(with: jsonData as Data, options: JSONSerialization.ReadingOptions.mutableContainers) as? NSDictionary {
if let responseA : NSArray = jsonResult["features"] as? NSArray {
print(responseA)
}
}
}
catch { print("Error while parsing: \(error)") }
}
I can pull all the information however, I am struggling to get the 'featureclass' information. What steps am I missing?
Thanks.
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Answer 1

I recommend to use Decodable in Swift 4. It's very simple and convenient
Create the structs
struct Collection : Decodable {
let type : String
let features : [Feature]
}
struct Feature : Decodable {
let type : String
let properties : Properties
// there is also geometry
}
struct Properties : Decodable {
let scalerank : Int
let name : String
let website : URL
let natlscale : Int
let featureclass : String
}
Decode the data and print the values for name and featureclass
let urlBar = Bundle.main.url(forResource: "bars", withExtension: "geojson")!
do {
let jsonData = try Data(contentsOf: urlBar)
let result = try JSONDecoder().decode(Collection.self, from: jsonData)
for feature in result.features {
print("name", feature.properties.name, "featureclass", feature.properties.featureclass)
}
} catch { print("Error while parsing: \(error)") }

Answer 2

Step by Step only, you can achieve that.
if let responseA : NSArray = jsonResult["features"] as? NSArray {
for dictVal in 0..<responseA.count
{
let featuresDict = responseA[dictVal] as! NSDictionary
let propertiesDict = featuresDict.value(forKey: "properties") as! NSDictionary
let featureClassName = propertiesDict.value(forKey: "featureclass") as! String
print(featureClassName)
}
}
Try to use this link for Complex JSON validation. You will get clarity.