/// <summary>
/// Initialize VectorTileFeature
/// </summary>
/// <param name="layer">Parent <see cref="VectorTileLayer" /></param>
public VectorTileFeature(VectorTileLayer layer, uint?clipBuffer = null, float scale = 1.0f)
{
Layer = layer;
_clipBuffer = clipBuffer;
_scale = scale;
Tags = new List <int>();
}
/// <summary>
/// Get a feature of the <see cref="VectorTileLayer" />
/// </summary>
/// <param name="layer"><see cref="VectorTileLayer" /> containing the feature</param>
/// <param name="data">Raw byte data of the feature</param>
/// <param name="validate">If true, run checks if the tile contains valid data. Decreases decoding speed.</param>
/// <param name="clippBuffer">
/// <para>'null': returns the geometries unaltered as they are in the vector tile. </para>
/// <para>Any value >=0 clips a border with the size around the tile. </para>
/// <para>These are not pixels but the same units as the 'extent' of the layer. </para>
/// </param>
/// <returns></returns>
public static VectorTileFeature GetFeature(
VectorTileLayer layer
, byte[] data
, bool validate = true
, uint?clipBuffer = null
, float scale = 1.0f
)
{
PbfReader featureReader = new PbfReader(data);
VectorTileFeature feat = new VectorTileFeature(layer, clipBuffer, scale);
bool geomTypeSet = false;
while (featureReader.NextByte())
{
int featureType = featureReader.Tag;
if (validate)
{
if (!ConstantsAsDictionary.FeatureType.ContainsKey(featureType))
{
throw new Exception(string.Format("Layer [{0}] has unknown feature type: {1}", layer.Name,
featureType));
}
}
switch ((FeatureType)featureType)
{
case FeatureType.Id:
feat.Id = (ulong)featureReader.Varint();
break;
case FeatureType.Tags:
List <int> tags = featureReader.GetPackedUnit32().Select(t => (int)t).ToList();
feat.Tags = tags;
break;
case FeatureType.Type:
int geomType = (int)featureReader.Varint();
if (validate)
{
if (!ConstantsAsDictionary.GeomType.ContainsKey(geomType))
{
throw new Exception(string.Format("Layer [{0}] has unknown geometry type tag: {1}",
layer.Name, geomType));
}
}
feat.GeometryType = (GeomType)geomType;
geomTypeSet = true;
break;
case FeatureType.Geometry:
if (null != feat.GeometryCommands)
{
throw new Exception(
string.Format("Layer [{0}], feature already has a geometry", layer.Name));
}
//get raw array of commands and coordinates
feat.GeometryCommands = featureReader.GetPackedUnit32();
break;
default:
featureReader.Skip();
break;
}
}
if (validate)
{
if (!geomTypeSet)
{
throw new Exception(string.Format("Layer [{0}]: feature missing geometry type", layer.Name));
}
if (null == feat.GeometryCommands)
{
throw new Exception(string.Format("Layer [{0}]: feature has no geometry", layer.Name));
}
if (0 != feat.Tags.Count % 2)
{
throw new Exception(string.Format("Layer [{0}]: uneven number of feature tag ids", layer.Name));
}
if (feat.Tags.Count > 0)
{
int maxKeyIndex = feat.Tags.Where((key, idx) => idx % 2 == 0).Max();
int maxValueIndex = feat.Tags.Where((key, idx) => (idx + 1) % 2 == 0).Max();
if (maxKeyIndex >= layer.Keys.Count)
{
throw new Exception(string.Format(
"Layer [{0}]: maximum key index equal or greater number of key elements", layer.Name));
}
if (maxValueIndex >= layer.Values.Count)
{
throw new Exception(string.Format(
"Layer [{0}]: maximum value index equal or greater number of value elements", layer.Name));
}
}
}
return(feat);
}
private VectorTileLayer getLayer(byte[] data)
{
VectorTileLayer layer = new VectorTileLayer(data);
PbfReader layerReader = new PbfReader(layer.Data);
while (layerReader.NextByte())
{
int layerType = layerReader.Tag;
if (_Validate)
{
if (!ConstantsAsDictionary.LayerType.ContainsKey(layerType))
{
throw new Exception(string.Format("Unknown layer type: {0}", layerType));
}
}
switch ((LayerType)layerType)
{
case LayerType.Version:
ulong version = (ulong)layerReader.Varint();
layer.Version = version;
break;
case LayerType.Name:
ulong strLength = (ulong)layerReader.Varint();
layer.Name = layerReader.GetString(strLength);
break;
case LayerType.Extent:
layer.Extent = (ulong)layerReader.Varint();
break;
case LayerType.Keys:
byte[] keyBuffer = layerReader.View();
string key = Encoding.UTF8.GetString(keyBuffer, 0, keyBuffer.Length);
layer.Keys.Add(key);
break;
case LayerType.Values:
byte[] valueBuffer = layerReader.View();
PbfReader valReader = new PbfReader(valueBuffer);
while (valReader.NextByte())
{
switch ((ValueType)valReader.Tag)
{
case ValueType.String:
byte[] stringBuffer = valReader.View();
string value = Encoding.UTF8.GetString(stringBuffer, 0, stringBuffer.Length);
layer.Values.Add(value);
break;
case ValueType.Float:
float snglVal = valReader.GetFloat();
layer.Values.Add(snglVal);
break;
case ValueType.Double:
double dblVal = valReader.GetDouble();
layer.Values.Add(dblVal);
break;
case ValueType.Int:
long i64 = valReader.Varint();
layer.Values.Add(i64);
break;
case ValueType.UInt:
long u64 = valReader.Varint();
layer.Values.Add(u64);
break;
case ValueType.SInt:
long s64 = valReader.Varint();
layer.Values.Add(s64);
break;
case ValueType.Bool:
long b = valReader.Varint();
layer.Values.Add(b == 1);
break;
default:
throw new Exception(string.Format(
NumberFormatInfo.InvariantInfo
, "NOT IMPLEMENTED valueReader.Tag:{0} valueReader.WireType:{1}"
, valReader.Tag
, valReader.WireType
));
//uncomment the following lines when not throwing!!
//valReader.Skip();
//break;
}
}
break;
case LayerType.Features:
layer.AddFeatureData(layerReader.View());
break;
default:
layerReader.Skip();
break;
}
}
if (_Validate)
{
if (string.IsNullOrEmpty(layer.Name))
{
throw new Exception("Layer has no name");
}
if (0 == layer.Version)
{
throw new Exception(string.Format(
"Layer [{0}] has invalid version. Only version 2.x of 'Mapbox Vector Tile Specification' (https://github.com/mapbox/vector-tile-spec) is supported.",
layer.Name));
}
if (2 != layer.Version)
{
throw new Exception(string.Format(
"Layer [{0}] has invalid version: {1}. Only version 2.x of 'Mapbox Vector Tile Specification' (https://github.com/mapbox/vector-tile-spec) is supported.",
layer.Name, layer.Version));
}
if (0 == layer.Extent)
{
throw new Exception(string.Format("Layer [{0}] has no extent.", layer.Name));
}
if (0 == layer.FeatureCount())
{
throw new Exception(string.Format("Layer [{0}] has no features.", layer.Name));
}
if (layer.Values.Count != layer.Values.Distinct().Count())
{
throw new Exception(string.Format("Layer [{0}]: duplicate attribute values found", layer.Name));
}
}
return(layer);
}
