/// <summary>
/// Reads GeoJson and returns the feature collection.
/// </summary>
/// <param name="jsonReader"></param>
/// <returns></returns>
internal static FeatureCollection ReadFeatureCollection(JsonReader jsonReader)
{
var type = string.Empty;
List<Feature> features = null;
while (jsonReader.Read())
{
if (jsonReader.TokenType == JsonToken.EndObject)
{ // end of geometry.
break;
}
if (jsonReader.TokenType == JsonToken.PropertyName)
{
if ((string)jsonReader.Value == "type")
{ // the geometry type.
type = jsonReader.ReadAsString();
}
else if ((string)jsonReader.Value == "features")
{ // the geometry.
features = GeoJsonConverter.ReadFeatureArray(jsonReader);
}
}
}
switch (type)
{
case "FeatureCollection":
if (features == null)
{
return new FeatureCollection();
}
return new FeatureCollection(features);
}
throw new Exception("Invalid type.");
}
/// <summary>
/// Reads GeoJson and returns the geometry.
/// </summary>
/// <param name="jsonReader"></param>
/// <returns></returns>
internal static Geometry ReadGeometry(JsonReader jsonReader)
{
var geometryType = string.Empty;
var coordinates = new List<object>();
List<Geometry> geometries = null;
while (jsonReader.Read())
{
if (jsonReader.TokenType == JsonToken.EndObject)
{ // end of geometry.
break;
}
if (jsonReader.TokenType == JsonToken.PropertyName)
{
if ((string)jsonReader.Value == "type")
{ // the geometry type.
geometryType = jsonReader.ReadAsString();
}
else if ((string)jsonReader.Value == "geometries")
{ // the geometries if a geometry collection.
geometries = GeoJsonConverter.ReadGeometryArray(jsonReader);
}
else if ((string)jsonReader.Value == "coordinates")
{ // the coordinates.
jsonReader.Read(); // move to first array start.
coordinates = GeoJsonConverter.ReadCoordinateArrays(jsonReader);
}
}
}
// data has been read, instantiate the actual object.
switch(geometryType)
{
case "Point":
return GeoJsonConverter.BuildPoint(coordinates);
case "LineString":
return GeoJsonConverter.BuildLineString(coordinates);
case "Polygon":
return GeoJsonConverter.BuildPolygon(coordinates);
case "MultiPoint":
return GeoJsonConverter.BuildMultiPoint(coordinates);
case "MultiLineString":
return GeoJsonConverter.BuildMultiLineString(coordinates);
case "MultiPolygon":
return GeoJsonConverter.BuildMultiPolygon(coordinates);
case "GeometryCollection":
return GeoJsonConverter.BuildGeometryCollection(geometries);
}
throw new Exception(string.Format("Unknown geometry type: {0}", geometryType));
}
/// <summary>
/// Reads GeoJson and returns the feature.
/// </summary>
/// <param name="jsonReader"></param>
/// <returns></returns>
internal static Feature ReadFeature(JsonReader jsonReader)
{
var type = string.Empty;
Geometry geometry = null;
GeometryAttributeCollection attributes = null;
while (jsonReader.Read())
{
if (jsonReader.TokenType == JsonToken.EndObject)
{ // end of geometry.
break;
}
if (jsonReader.TokenType == JsonToken.PropertyName)
{
if ((string)jsonReader.Value == "type")
{ // the geometry type.
type = jsonReader.ReadAsString();
}
else if ((string)jsonReader.Value == "geometry")
{ // the geometry.
geometry = GeoJsonConverter.ReadGeometry(jsonReader);
}
else if ((string)jsonReader.Value == "properties")
{ // the properties/attributes.
attributes = GeoJsonConverter.ReadAttributes(jsonReader);
}
}
}
switch(type)
{
case "Feature":
if(geometry == null)
{
throw new Exception("No geometry found.");
}
if(attributes != null)
{
return new Feature(geometry, attributes);
}
return new Feature(geometry);
}
throw new Exception("Invalid type.");
}
