QGeoJson Class

Header:	#include <QGeoJson>
qmake:	QT += location
Since:	Qt 5.13

List of all members, including inherited members

Static Public Members

QJsonDocument	exportGeoJson(const QVariantList &geoData)
QVariantList	importGeoJson(const QJsonDocument &geoJson)
QString	toString(const QVariantList &geoData)

Detailed Description

QGeoJson class can be used to convert between a GeoJSON document (see the Wikipedia page, RFC) and a QVariantList of QVariantMap elements ready to be used as Model in a MapItemView. WARNING! This private class is part of Qt labs, thus not stable API, it is part of the experimental components of QtLocation. Until it is promoted to public API, it may be subject to source and binary-breaking changes.

Importing GeoJSON

The importGeoJson() method accepts a QJsonDocument from which it extracts a single JSON object, since the GeoJSON RFC expects that a valid GeoJSON Document has in its root a single JSON object. This method doesn't perform any validation on the input. The importer returns a QVariantList containing a single QVariantMap. This map has always at least 2 (key, value) pairs. The first one has type as key, and the corresponding value is a string identifying the GeoJSON type. This value can be one of the GeoJSON object types: Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon, GeometryCollection, FeatureCollection. The second pair has data as key, and the corresponding value can be either a QGeoShape or a list, depending on the GeoJSON type. The next section provides details about this node. The Feature type is converted into the type of the geometry contained within, with an additional (key, value) pair, where the key is properties and the value is a QVariantMap. Thus, a feature Map is distinguishable from the corresponding geometry, by looking for a properties member.

Structure of the data node

For the single type geometry objects (Point, LineString, and Polygon), the value corresponding to the data key is a QGeoShape:

When the type is Point, the data is a QGeoCircle with the point coordinates stored in the center property.
For example, the following GeoJSON document contains a Point geometry:
```
{
  "type" : "Point",
  "data" : [60.0, 11.0]
}
```
it is converted to a QVariantMap with the following structure:
```
{
  type : Point
  data : QGeoCircle({60.000, 11.000}, -1)
}
```
When the type is LineString the data ia a QGeoPath.
For example, the following GeoJSON document contains a LineString geometry:
```
{
    "type" : "LineString",
    "coordinates" : [[13.5, 43],[10.73, 59.92]]
}
```
it is converted to a QVariantMap with the following structure:
```
{
  type : LineString,
  data : QGeoPath([{43.000, 13.500}, {59.920, 10.730}])
}
```

When the type is Polygon, the data is a QGeoPolygon (holes are supported).

For example, the following GeoJSON document contains a Polygon geometry:

{
    "type" : "Polygon",
    "coordinates" : [
      [[17.13, 51.11],
       [30.54, 50.42],
       [26.70, 58.36],
       [17.13, 51.11]]
    ],
    "bbox" : [60, 60, -60, -60]

}