private Geometry ReadLineString(TileGeometryTransform tgs, IList <uint> geometry)
{
int currentIndex = 0; int currentX = 0; int currentY = 0;
var sequences = ReadCoordinateSequences(tgs, geometry, ref currentIndex, ref currentX, ref currentY);
return(CreateLineal(sequences));
}
/// <summary>
/// Reads a Vector Tile stream.
/// </summary>
/// <param name="stream">Vector tile stream.</param>
/// <param name="tileDefinition">Tile information.</param>
/// <param name="idAttributeName">Optional. Specifies the name of the attribute that the vector tile feature's ID should be stored in the NetTopologySuite Features AttributeTable.</param>
/// <returns></returns>
public VectorTile Read(Stream stream, Tiles.Tile tileDefinition, string idAttributeName)
{
// Deserialize the tile
var tile = ProtoBuf.Serializer.Deserialize <Mapbox.Tile>(stream);
var vectorTile = new VectorTile {
TileId = tileDefinition.Id
};
foreach (var mbTileLayer in tile.Layers)
{
Debug.Assert(mbTileLayer.Version == 2U);
var tgs = new TileGeometryTransform(tileDefinition, mbTileLayer.Extent);
var layer = new Layer {
Name = mbTileLayer.Name
};
foreach (var mbTileFeature in mbTileLayer.Features)
{
var feature = ReadFeature(tgs, mbTileLayer, mbTileFeature, idAttributeName);
layer.Features.Add(feature);
}
vectorTile.Layers.Add(layer);
}
return(vectorTile);
}
private Geometry ReadPolygon(TileGeometryTransform tgs, IList <uint> geometry)
{
int currentIndex = 0; int currentX = 0; int currentY = 0;
var sequences = ReadCoordinateSequences(tgs, geometry, ref currentIndex, ref currentX, ref currentY, 1);
return(CreatePolygonal(sequences));
}
private static IEnumerable <uint> Encode(IPolygonal polygonal, TileGeometryTransform tgt, int zoom)
{
var geometry = (Geometry)polygonal;
//Test the whole polygon geometry is larger than a single pixel.
if (IsGreaterThanOnePixelOfTile(geometry, zoom))
{
int currentX = 0, currentY = 0;
for (int i = 0; i < geometry.NumGeometries; i++)
{
var polygon = (Polygon)geometry.GetGeometryN(i);
//Test that individual polygons are larger than a single pixel.
if (!IsGreaterThanOnePixelOfTile(polygon, zoom))
{
continue;
}
foreach (uint encoded in Encode(polygon.Shell.CoordinateSequence, tgt, ref currentX, ref currentY, true, false))
{
yield return(encoded);
}
foreach (var hole in polygon.InteriorRings)
{
foreach (uint encoded in Encode(hole.CoordinateSequence, tgt, ref currentX, ref currentY, true, true))
{
yield return(encoded);
}
}
}
}
}
private static IEnumerable <uint> Encode(IPuntal puntal, TileGeometryTransform tgt)
{
const int CoordinateIndex = 0;
var geometry = (Geometry)puntal;
int currentX = 0, currentY = 0;
var parameters = new List <uint>();
for (int i = 0; i < geometry.NumGeometries; i++)
{
var point = (Point)geometry.GetGeometryN(i);
(int x, int y) = tgt.Transform(point.CoordinateSequence, CoordinateIndex, ref currentX, ref currentY);
if (i == 0 || x > 0 || y > 0)
{
parameters.Add(GenerateParameterInteger(x));
parameters.Add(GenerateParameterInteger(y));
}
}
// Return result
yield return(GenerateCommandInteger(MapboxCommandType.MoveTo, parameters.Count / 2));
foreach (uint parameter in parameters)
{
yield return(parameter);
}
}
private IFeature ReadFeature(TileGeometryTransform tgs, Tile.Layer mbTileLayer, Tile.Feature mbTileFeature, string idAttributeName)
{
var geometry = ReadGeometry(tgs, mbTileFeature.Type, mbTileFeature.Geometry);
var attributes = ReadAttributeTable(mbTileFeature, mbTileLayer.Keys, mbTileLayer.Values);
//Check to see if an id value is already captured in the attributes, if not, add it.
if (!string.IsNullOrEmpty(idAttributeName) && !mbTileLayer.Keys.Contains(idAttributeName))
{
ulong id = mbTileFeature.Id;
attributes.Add(idAttributeName, id);
}
return(new Feature(geometry, attributes));
}
private static IEnumerable <uint> Encode(ILineal lineal, TileGeometryTransform tgt)
{
var geometry = (Geometry)lineal;
int currentX = 0, currentY = 0;
for (int i = 0; i < geometry.NumGeometries; i++)
{
var lineString = (LineString)geometry.GetGeometryN(i);
foreach (uint encoded in Encode(lineString.CoordinateSequence, tgt, ref currentX, ref currentY, false))
{
yield return(encoded);
}
}
}
private Geometry ReadGeometry(TileGeometryTransform tgs, Tile.GeomType type, IList <uint> geometry)
{
switch (type)
{
case Tile.GeomType.Point:
return(ReadPoint(tgs, geometry));
case Tile.GeomType.LineString:
return(ReadLineString(tgs, geometry));
case Tile.GeomType.Polygon:
return(ReadPolygon(tgs, geometry));
}
return(null);
}
private CoordinateSequence[] ReadSinglePointSequences(TileGeometryTransform tgs, IList <uint> geometry,
int numSequences, ref int currentIndex, ref int currentX, ref int currentY)
{
var res = new CoordinateSequence[numSequences];
var currentPosition = (currentX, currentY);
for (int i = 0; i < numSequences; i++)
{
res[i] = _factory.CoordinateSequenceFactory.Create(1, 2);
currentPosition = ParseOffset(currentPosition, geometry, ref currentIndex);
TransformOffsetAndAddToSequence(tgs, currentPosition, res[i], 0);
}
currentX = currentPosition.currentX;
currentY = currentPosition.currentY;
return(res);
}
private void TransformOffsetAndAddToSequence(TileGeometryTransform tgs, (int x, int y) localPosition, CoordinateSequence sequence, int index)
private CoordinateSequence[] ReadCoordinateSequences(
TileGeometryTransform tgs, IList <uint> geometry,
ref int currentIndex, ref int currentX, ref int currentY, int buffer = 0, bool forPoint = false)
{
(var command, int count) = ParseCommandInteger(geometry[currentIndex]);
Debug.Assert(command == MapboxCommandType.MoveTo);
if (count > 1)
{
currentIndex++;
return(ReadSinglePointSequences(tgs, geometry, count, ref currentIndex, ref currentX, ref currentY));
}
var sequences = new List <CoordinateSequence>();
var currentPosition = (currentX, currentY);
while (currentIndex < geometry.Count)
{
(command, count) = ParseCommandInteger(geometry[currentIndex++]);
Debug.Assert(command == MapboxCommandType.MoveTo);
Debug.Assert(count == 1);
// Read the current position
currentPosition = ParseOffset(currentPosition, geometry, ref currentIndex);
if (!forPoint)
{
// Read the next command (should be LineTo)
(command, count) = ParseCommandInteger(geometry[currentIndex++]);
if (command != MapboxCommandType.LineTo)
{
count = 0;
}
}
else
{
count = 0;
}
// Create sequence, add starting point
var sequence = _factory.CoordinateSequenceFactory.Create(1 + count + buffer, 2);
int sequenceIndex = 0;
TransformOffsetAndAddToSequence(tgs, currentPosition, sequence, sequenceIndex++);
// Read and add offsets
for (int i = 1; i <= count; i++)
{
currentPosition = ParseOffset(currentPosition, geometry, ref currentIndex);
TransformOffsetAndAddToSequence(tgs, currentPosition, sequence, sequenceIndex++);
}
// Check for ClosePath command
if (currentIndex < geometry.Count)
{
(command, _) = ParseCommandInteger(geometry[currentIndex]);
if (command == MapboxCommandType.ClosePath)
{
Debug.Assert(buffer > 0);
sequence.SetOrdinate(sequenceIndex, Ordinate.X, sequence.GetOrdinate(0, Ordinate.X));
sequence.SetOrdinate(sequenceIndex, Ordinate.Y, sequence.GetOrdinate(0, Ordinate.Y));
currentIndex++;
sequenceIndex++;
}
}
Debug.Assert(sequenceIndex == sequence.Count);
sequences.Add(sequence);
}
// update current position values
currentX = currentPosition.currentX;
currentY = currentPosition.currentY;
return(sequences.ToArray());
}
/// <summary>
/// Writes the tile to the given stream.
/// </summary>
/// <param name="vectorTile">The vector tile.</param>
/// <param name="stream">The stream to write to.</param>
/// <param name="extent">The extent.</param>
/// <param name="idAttributeName">The name of an attribute property to use as the ID for the Feature. Vector tile feature ID's should be integer or ulong numbers.</param>
public static void Write(this VectorTile vectorTile, Stream stream, uint extent = 4096, string idAttributeName = "id")
{
var tile = new Tiles.Tile(vectorTile.TileId);
var tgt = new TileGeometryTransform(tile, extent);
var mapboxTile = new Mapbox.Tile();
foreach (var localLayer in vectorTile.Layers)
{
var layer = new Mapbox.Tile.Layer {
Version = 2, Name = localLayer.Name, Extent = extent
};
var keys = new Dictionary <string, uint>();
var values = new Dictionary <Tile.Value, uint>();
foreach (var localLayerFeature in localLayer.Features)
{
var feature = new Mapbox.Tile.Feature();
// Encode geometry
switch (localLayerFeature.Geometry)
{
case IPuntal puntal:
feature.Type = Tile.GeomType.Point;
feature.Geometry.AddRange(Encode(puntal, tgt));
break;
case ILineal lineal:
feature.Type = Tile.GeomType.LineString;
feature.Geometry.AddRange(Encode(lineal, tgt));
break;
case IPolygonal polygonal:
feature.Type = Tile.GeomType.Polygon;
feature.Geometry.AddRange(Encode(polygonal, tgt, tile.Zoom));
break;
default:
feature.Type = Tile.GeomType.Unknown;
break;
}
// If geometry collapsed during encoding, we don't add the feature at all
if (feature.Geometry.Count == 0)
{
continue;
}
// Translate attributes for feature
AddAttributes(feature.Tags, keys, values, localLayerFeature.Attributes);
//Try and retrieve an ID from the attributes.
var id = localLayerFeature.Attributes.GetOptionalValue(idAttributeName);
//Converting ID to string, then trying to parse. This will handle situations will ignore situations where the ID value is not actually an integer or ulong number.
if (id != null && ulong.TryParse(id.ToString(), out ulong idVal))
{
feature.Id = idVal;
}
// Add feature to layer
layer.Features.Add(feature);
}
layer.Keys.AddRange(keys.Keys);
layer.Values.AddRange(values.Keys);
mapboxTile.Layers.Add(layer);
}
ProtoBuf.Serializer.Serialize <Tile>(stream, mapboxTile);
}
private static IEnumerable <uint> Encode(CoordinateSequence sequence, TileGeometryTransform tgt,
ref int currentX, ref int currentY,
bool ring = false, bool ccw = false)
{
// how many parameters for LineTo command
int count = sequence.Count;
// if we have a ring we need to check orientation
if (ring)
{
if (ccw != Algorithm.Orientation.IsCCW(sequence))
{
sequence = sequence.Copy();
CoordinateSequences.Reverse(sequence);
}
}
var encoded = new List <uint>();
// Start point
encoded.Add(GenerateCommandInteger(MapboxCommandType.MoveTo, 1));
var position = tgt.Transform(sequence, 0, ref currentX, ref currentY);
encoded.Add(GenerateParameterInteger(position.x));
encoded.Add(GenerateParameterInteger(position.y));
// Add LineTo command (stub)
int lineToCount = 0;
encoded.Add(GenerateCommandInteger(MapboxCommandType.LineTo, lineToCount));
for (int i = 1; i < count; i++)
{
position = tgt.Transform(sequence, i, ref currentX, ref currentY);
if (position.x != 0 || position.y != 0)
{
encoded.Add(GenerateParameterInteger(position.x));
encoded.Add(GenerateParameterInteger(position.y));
lineToCount++;
}
}
if (lineToCount > 0)
{
encoded[3] = GenerateCommandInteger(MapboxCommandType.LineTo, lineToCount);
}
// Validate encoded data
if (ring)
{
// A ring has 1 MoveTo and 1 LineTo command.
// A ring is only valid if we have at least 3 points, otherwise collapse
if (encoded.Count - 2 >= 6)
{
encoded.Add(GenerateCommandInteger(MapboxCommandType.ClosePath, 1));
}
else
{
encoded.Clear();
}
}
else
{
// A line has 1 MoveTo and 1 LineTo command.
// A line is valid if it has at least 2 points
if (encoded.Count - 2 < 4)
{
encoded.Clear();
}
}
return(encoded);
}
