/// <summary>
/// Creates a Point using the next token in the stream.
/// </summary>
/// <param name="tokenizer">
/// Tokenizer over a stream of text in Well-known Text
/// format. The next tokens must form a <Point Text>.
/// </param>
/// <returns>
/// Returns a Point specified by the next token in
/// the stream.
/// </returns>
/// <remarks>
/// ParseException is thrown if an unexpected token is encountered.
/// </remarks>
private static MapPoint ReadPointText(WktStreamTokenizer tokenizer)
{
var nextToken = GetNextEmptyOrOpener(tokenizer);
if (nextToken == "EMPTY")
{
throw new Exception("Empty Point");
}
var p = new MapPoint(GetNextNumber(tokenizer), GetNextNumber(tokenizer));
GetNextCloser(tokenizer);
return(p);
}
/// <summary>
/// Creates a <see cref="Polyline" /> using the next token in the stream.
/// </summary>
/// <param name="tokenizer">
/// tokenizer over a stream of text in Well-known Text format. The next tokens must form a
/// MultiLineString Text
/// </param>
/// <returns>a <see cref="Polyline" /> specified by the next token in the stream</returns>
private static Polyline ReadMultiLineStringText(WktStreamTokenizer tokenizer)
{
var nextToken = GetNextEmptyOrOpener(tokenizer);
if (nextToken == "EMPTY")
{
throw new Exception("Empty Multiline");
}
var lines = new PolylineBuilder(GetCoordinates(tokenizer));
nextToken = GetNextCloserOrComma(tokenizer);
while (nextToken == ",")
{
lines.AddPart(GetCoordinates(tokenizer));
nextToken = GetNextCloserOrComma(tokenizer);
}
return(lines.ToGeometry());
}
/// <summary>
/// Creates a Polygon using the next token in the stream.
/// </summary>
/// <param name="tokenizer">
/// Tokenizer over a stream of text in Well-known Text
/// format. The next tokens must form a <Polygon Text>.
/// </param>
/// <param name="exteriorRingCcw"></param>
/// <param name="exteriorRingCcwSpecified"></param>
/// <returns>
/// Returns a Polygon specified by the next token
/// in the stream
/// </returns>
/// <remarks>
/// ParseException is thown if the coordinates used to create the Polygon
/// shell and holes do not form closed linestrings, or if an unexpected
/// token is encountered.
/// </remarks>
private static Polygon ReadPolygonText(WktStreamTokenizer tokenizer, bool exteriorRingCcw = false,
bool exteriorRingCcwSpecified = false)
{
var nextToken = GetNextEmptyOrOpener(tokenizer);
if (nextToken == "EMPTY")
{
throw new Exception("Empty Polygon");
}
var exteriorRing = GetCoordinates(tokenizer);
IEnumerable <MapPoint> firstRing;
// Exterior ring. Force it to be CW/CCW to match the first exterior ring of the multipolygon, if it is part of a multipolygon
if (exteriorRingCcwSpecified)
{
firstRing = Algorithms.IsCcw(exteriorRing) != exteriorRingCcw?Reverse(exteriorRing) : exteriorRing;
}
else
{
firstRing = exteriorRing;
}
var polygonBuilder = new PolygonBuilder(firstRing);
nextToken = GetNextCloserOrComma(tokenizer);
while (nextToken == ",")
{
//Add holes
var interiorRing = GetCoordinates(tokenizer);
var correctedRing = interiorRing;
// Make sure interior rings go in the opposite direction of the exterior rings
if (Algorithms.IsCcw(interiorRing) == exteriorRingCcw)
{
correctedRing = Reverse(interiorRing);
}
polygonBuilder.AddPart(correctedRing); //interior rings
nextToken = GetNextCloserOrComma(tokenizer);
}
return(polygonBuilder.ToGeometry());
}
/// <summary>
/// Returns the next array of Coordinates in the stream.
/// </summary>
/// <param name="tokenizer">
/// Tokenizer over a stream of text in Well-known Text format. The
/// next element returned by the stream should be "(" (the beginning of "(x1 y1, x2 y2, ..., xn yn)" or
/// "EMPTY".
/// </param>
/// <returns>
/// The next array of Coordinates in the stream, or an empty array of "EMPTY" is the
/// next element returned by the stream.
/// </returns>
private static IEnumerable <MapPoint> GetCoordinates(WktStreamTokenizer tokenizer)
{
var coordinates = new PointCollection();
var nextToken = GetNextEmptyOrOpener(tokenizer);
if (nextToken == "EMPTY")
{
return(coordinates);
}
var externalCoordinate = new MapPoint(GetNextNumber(tokenizer), GetNextNumber(tokenizer));
coordinates.Add(externalCoordinate);
nextToken = GetNextCloserOrComma(tokenizer);
while (nextToken == ",")
{
var internalCoordinate = new MapPoint(GetNextNumber(tokenizer), GetNextNumber(tokenizer));
coordinates.Add(internalCoordinate);
nextToken = GetNextCloserOrComma(tokenizer);
}
return(coordinates);
}
/// <summary>
/// Returns the next number in the stream.
/// </summary>
/// <param name="tokenizer">
/// Tokenizer over a stream of text in Well-known text format. The next token
/// must be a number.
/// </param>
/// <returns>Returns the next number in the stream.</returns>
/// <remarks>
/// ParseException is thrown if the next token is not a number.
/// </remarks>
private static double GetNextNumber(WktStreamTokenizer tokenizer)
{
tokenizer.NextToken();
return(tokenizer.GetNumericValue());
}
/// <summary>
/// Creates a LineString using the next token in the stream.
/// </summary>
/// <param name="tokenizer">
/// Tokenizer over a stream of text in Well-known Text format. The next
/// tokens must form a LineString Text.
/// </param>
/// <returns>Returns a LineString specified by the next token in the stream.</returns>
/// <remarks>
/// ParseException is thrown if an unexpected token is encountered.
/// </remarks>
private static Polyline ReadLineStringText(WktStreamTokenizer tokenizer)
{
return(new Polyline(GetCoordinates(tokenizer)));
}
/// <summary>
/// Converts a Well-known Text representation to a <see cref="Geometry" />.
/// </summary>
/// <param name="reader">
/// A Reader which will return a Geometry Tagged Text
/// string (see the OpenGIS Simple Features Specification)
/// </param>
/// <returns>
/// Returns a <see cref="Geometry" /> read from StreamReader.
/// An exception will be thrown if there is a parsing problem.
/// </returns>
public static Geometry GeometryFromWkt(TextReader reader)
{
var tokenizer = new WktStreamTokenizer(reader);
return(ArcGISRuntimeWKT.GeometryFromWkt.ReadGeometryTaggedText(tokenizer));
}
