/// <summary>
/// Convert the given Overpass query result to GeoJSON.
/// </summary>
/// <param name="ResultTask">A Overpass query result task.</param>
public static Task <JObject> ToGeoJSON(this Task <OverpassResult> ResultTask)
{
return(ResultTask.ContinueWith(task => {
// The order of the nodes, ways and relations seem not to be sorted by default!
#region 1st: Add all nodes
Node Node;
var Nodes = new Dictionary <UInt64, Node>();
foreach (var element in ResultTask.Result.Elements)
{
// {
// "type": "node",
// "id": 35304749,
// "lat": 50.8926376,
// "lon": 11.6023278,
// "tags": {
// "highway": "bus_stop",
// "name": "Lobeda",
// "operator": "JES",
// "wheelchair": "yes"
// }
// }
if (element["type"].ToString() == "node")
{
Node = Node.Parse(element);
if (Nodes.ContainsKey(Node.Id))
{
Console.WriteLine("Duplicate node id detected!");
}
else
{
Nodes.Add(Node.Id, Node);
}
}
}
#endregion
#region 2nd: Add all ways
Way Way;
var Ways = new Dictionary <UInt64, Way>();
foreach (var element in ResultTask.Result.Elements)
{
// {
// "type": "way",
// "id": 154676600,
// "nodes": [
// 747761494,
// 582476538,
// 582476541,
// 582476543,
// 1671750275,
// 407850195,
// 407850192,
// 407850188,
// 1671750245,
// 1671750330,
// 1671750408,
// 1671750415,
// 1671750433,
// 1671750438,
// 1671750441,
// 747761494
// ],
// "tags": {
// "landuse": "farm"
// }
// }
if (element["type"].ToString() == "way")
{
Way = Way.Parse(element,
NodeResolver: nodeId => Nodes[nodeId]);
if (Ways.ContainsKey(Way.Id))
{
Console.WriteLine("Duplicate way id detected!");
}
else
{
Ways.Add(Way.Id, Way);
}
}
}
#endregion
#region 3rd: Add all relations
Relation Relation;
var Relations = new Dictionary <UInt64, Relation>();
foreach (var element in ResultTask.Result.Elements)
{
// {
// "type": "relation",
// "id": 3806843,
// "members": [
// {
// "type": "way",
// "ref": 71002045,
// "role": "outer"
// },
// {
// "type": "way",
// "ref": 286959663,
// "role": "outer"
// },
// {
// "type": "way",
// "ref": 286959664,
// "role": "outer"
// },
// {
// "type": "way",
// "ref": 286959641,
// "role": "outer"
// }
// ],
// "tags": {
// "landuse": "farm",
// "type": "multipolygon"
// }
// }
if (element["type"].ToString() == "relation")
{
Relation = Relation.Parse(element,
NodeResolver: nodeId => Nodes[nodeId],
WayResolver: wayId => Ways [wayId]);
if (Relations.ContainsKey(Relation.Id))
{
Console.WriteLine("Duplicate relation id detected!");
}
else
{
Relations.Add(Relation.Id, Relation);
}
}
}
#endregion
// {
// "type": "FeatureCollection",
// "generator": "overpass-turbo",
// "copyright": "The data included in this document is from www.openstreetmap.org. The data is made available under ODbL.",
// "timestamp": "2014-11-29T23:08:02Z",
// "features": [ ]
// }
return new JObject(
new JProperty("type", "FeatureCollection"),
new JProperty("generator", "GraphDefined OSM Importer"),
new JProperty("copyright", ResultTask.Result.Copyright),
new JProperty("timestamp", DateTime.Now.ToIso8601()),
new JProperty("features", new JArray(Nodes.Values.
// Do not include nodes which only have a geo coordinate, but not tags!
// (They will be most likely only be useful within ways or relations)
Where(n => n.Tags.Count > 0).
Select(n => n.ToGeoJSON())).
Concat(
new JArray(Ways.Values.
// Do not include ways which do not have any tags!
// (They will be most likely only be useful within relations)
Where(w => w.Tags.Count > 0).
Select(w => w.ToGeoJSON()))).
Concat(
new JArray(Relations.Values.
// Do not include nodes which only have a geo coordinate, but not tags!
// (They will be most likely only be useful within ways or relations)
//Where (r => r.Tags.Count > 0).
Select(r => r.ToGeoJSON())))
)
);
}));
}
/// <summary>
/// Convert the given OSM relation to a GeoJSON line feature.
/// </summary>
/// <param name="Relation">An OSM relation.</param>
public static JObject ToGeoJSON(this Relation Relation)
{
// {
// "type": "Feature",
// "id": "way/305352912",
// "properties": {
// "@id": "way/305352912",
// },
// "geometry": {
// "type": "LineString",
// "coordinates": [ [ 11.6023278, 50.8926376 ], [ 11.5054540, 50.7980146 ], [ 11.6023278, 50.8926376 ] ]
// }
// }
// https://wiki.openstreetmap.org/wiki/Overpass_turbo/Polygon_Features
// 1) Combine all ways into a single big list of geo coordinate (it's a puzzle! Some ways must be reversed in order to find matches!)
// 2) Check if first geo coordinate is the same as the last
// 3) If yes => polygon (exceptions see wiki link)
// Relation.Ways.Select(Way => new JArray(Way.Nodes.Select(Node => new JArray(Node.Longitude, Node.Latitude))))
var RemainingGeoFeatures = Relation.Ways.Select(Way => new GeoFeature(Way.Nodes.Select(Node => new GeoCoord(Node.Longitude, Node.Latitude)))).ToList();
var ResultList = new List <GeoFeature>();
Byte Found = 0;
GeoFeature CurrentGeoFeature;
if (Relation.Id == 3484638)
{
}
//if (Relation.Tags["type"].ToString() != "multipolygon")
//{
// Console.WriteLine("Broken OSM multipolygon relation found!");
//}
do
{
CurrentGeoFeature = RemainingGeoFeatures.RemoveAndReturnFirst();
// The current geo feature is closed -> a polygon!
if (Relation.Tags["type"].ToString() != "route" &&
CurrentGeoFeature.GeoCoordinates.First() == CurrentGeoFeature.GeoCoordinates.Last())
{
CurrentGeoFeature.Type = GeoFeature.GeoType.Polygon;
ResultList.Add(CurrentGeoFeature);
}
// The current geo feature is not closed
// Try to extend the geo feature by finding fitting other geo features
else
{
do
{
Found = 0;
foreach (var AdditionalPath in RemainingGeoFeatures)
{
if (AdditionalPath.GeoCoordinates.First() == CurrentGeoFeature.GeoCoordinates.Last())
{
RemainingGeoFeatures.Remove(AdditionalPath);
// Skip first GeoCoordinate as it is redundant!
CurrentGeoFeature.GeoCoordinates.AddRange(AdditionalPath.GeoCoordinates);//.Skip(1));
Found = 1;
break;
}
else if (AdditionalPath.GeoCoordinates.Last() == CurrentGeoFeature.GeoCoordinates.Last())
{
RemainingGeoFeatures.Remove(AdditionalPath);
// Skip first GeoCoordinate as it is redundant!
CurrentGeoFeature.GeoCoordinates.AddRange(AdditionalPath.GeoCoordinates.ReverseAndReturn());//.Skip(1));
Found = 1;
break;
}
else if (AdditionalPath.GeoCoordinates.First() == CurrentGeoFeature.GeoCoordinates.First())
{
RemainingGeoFeatures.Remove(AdditionalPath);
CurrentGeoFeature.GeoCoordinates.Reverse();
// Skip first GeoCoordinate as it is redundant!
CurrentGeoFeature.GeoCoordinates.AddRange(AdditionalPath.GeoCoordinates);//.Skip(1));
Found = 1;
break;
}
else if (AdditionalPath.GeoCoordinates.Last() == CurrentGeoFeature.GeoCoordinates.First())
{
RemainingGeoFeatures.Remove(AdditionalPath);
CurrentGeoFeature.GeoCoordinates.Reverse();
// Skip first GeoCoordinate as it is redundant!
CurrentGeoFeature.GeoCoordinates.AddRange(AdditionalPath.GeoCoordinates.ReverseAndReturn());//.Skip(1));
Found = 1;
break;
}
}
} while (RemainingGeoFeatures.Count > 0 && Found > 0);
CurrentGeoFeature.Type = (Relation.Tags["type"].ToString() != "route" &&
CurrentGeoFeature.GeoCoordinates.First() == CurrentGeoFeature.GeoCoordinates.Last())
? GeoFeature.GeoType.Polygon
: GeoFeature.GeoType.LineString;
ResultList.Add(CurrentGeoFeature);
}
} while (RemainingGeoFeatures.Count > 0);
JProperty FeatureGeometry = null;
if (ResultList.Count == 1)
{
if (ResultList.First().Type == GeoFeature.GeoType.Polygon)
{
FeatureGeometry = new JProperty("geometry", new JObject(
new JProperty("type", "Polygon"),
new JProperty("coordinates", new JArray()
{
new JArray(CurrentGeoFeature.GeoCoordinates.Select(geo => new JArray(geo.Longitude, geo.Latitude)))
})
));
}
else
{
FeatureGeometry = new JProperty("geometry", new JObject(
new JProperty("type", "LineString"),
new JProperty("coordinates", new JArray(CurrentGeoFeature.GeoCoordinates.Select(geo => new JArray(geo.Longitude, geo.Latitude))))
));
}
}
else
{
if (ResultList.First().Type == GeoFeature.GeoType.Polygon)
{
FeatureGeometry = new JProperty("geometry", new JObject(
new JProperty("type", "Polygon"),
new JProperty("coordinates", new JArray(ResultList.Select(items => new JArray(items.GeoCoordinates.Select(geo => new JArray(geo.Longitude, geo.Latitude))))))
));
}
else
{
FeatureGeometry = new JProperty("geometry", new JObject(
new JProperty("type", "MultiLineString"),
new JProperty("coordinates", new JArray(ResultList.Select(items => new JArray(items.GeoCoordinates.Select(geo => new JArray(geo.Longitude, geo.Latitude))))))
));
}
}
return(new JObject(
new JProperty("type", "Feature"),
new JProperty("id", "relation/" + Relation.Id),
new JProperty("properties", new JObject(
new List <JProperty>()
{
new JProperty("@id", "relation/" + Relation.Id)
}.
AddAndReturnList(Relation.Tags.Select(kvp => new JProperty(kvp.Key, kvp.Value))).
ToArray()
)),
FeatureGeometry
));
}