private static List <GeoCoordinate> ParseCoordinates(WellKnownTextTokenizer tokenizer)
{
var coordinates = new List <GeoCoordinate>();
if (IsNumberNext(tokenizer) || tokenizer.NextToken() == TokenType.LParen)
{
coordinates.Add(ParseCoordinate(tokenizer));
}
while (NextCloserOrComma(tokenizer) == TokenType.Comma)
{
var isOpenParen = false;
if (IsNumberNext(tokenizer) || (isOpenParen = tokenizer.NextToken() == TokenType.LParen))
{
coordinates.Add(ParseCoordinate(tokenizer));
}
if (isOpenParen)
{
NextCloser(tokenizer);
}
}
return(coordinates);
}
private static void NextCloser(WellKnownTextTokenizer tokenizer)
{
if (tokenizer.NextToken() != TokenType.RParen)
{
throw new GeoWKTException(
$"Expected {(char)WellKnownTextTokenizer.RParen} " +
$"but found: {tokenizer.TokenString()}", tokenizer.LineNumber, tokenizer.Position);
}
}
private static MultiPointGeoShape ParseMultiPoint(WellKnownTextTokenizer tokenizer)
{
if (NextEmptyOrOpen(tokenizer) == TokenType.Word)
{
return(null);
}
var coordinates = ParseCoordinates(tokenizer);
return(new MultiPointGeoShape(coordinates));
}
private static LineStringGeoShape ParseLineString(WellKnownTextTokenizer tokenizer)
{
if (NextEmptyOrOpen(tokenizer) == TokenType.Word)
{
return(null);
}
var coordinates = ParseCoordinates(tokenizer);
return(new LineStringGeoShape(coordinates));
}
private static PolygonGeoShape ParsePolygon(WellKnownTextTokenizer tokenizer)
{
if (NextEmptyOrOpen(tokenizer) == TokenType.Word)
{
return(null);
}
var coordinates = ParseCoordinateLists(tokenizer);
return(new PolygonGeoShape(coordinates));
}
private static PointGeoShape ParsePoint(WellKnownTextTokenizer tokenizer)
{
if (NextEmptyOrOpen(tokenizer) == TokenType.Word)
{
return(null);
}
var point = new PointGeoShape(ParseCoordinate(tokenizer));
NextCloser(tokenizer);
return(point);
}
private static TokenType NextCloserOrComma(WellKnownTextTokenizer tokenizer)
{
var token = tokenizer.NextToken();
if (token == TokenType.Comma || token == TokenType.RParen)
{
return(token);
}
throw new GeoWKTException(
$"Expected {(char)WellKnownTextTokenizer.Comma} or {(char)WellKnownTextTokenizer.RParen} " +
$"but found: {tokenizer.TokenString()}", tokenizer.LineNumber, tokenizer.Position);
}
private static TokenType NextEmptyOrOpen(WellKnownTextTokenizer tokenizer)
{
var token = tokenizer.NextToken();
if (token == TokenType.LParen ||
token == TokenType.Word && tokenizer.TokenValue.Equals(WellKnownTextTokenizer.Empty, StringComparison.OrdinalIgnoreCase))
{
return(token);
}
throw new GeoWKTException(
$"Expected {WellKnownTextTokenizer.Empty} or {(char)WellKnownTextTokenizer.LParen} " +
$"but found: {tokenizer.TokenString()}", tokenizer.LineNumber, tokenizer.Position);
}
private static GeoCoordinate ParseCoordinate(WellKnownTextTokenizer tokenizer)
{
var lon = NextNumber(tokenizer);
var lat = NextNumber(tokenizer);
double?z = null;
if (IsNumberNext(tokenizer))
{
z = NextNumber(tokenizer);
}
return(z == null
? new GeoCoordinate(lat, lon)
: new GeoCoordinate(lat, lon, z.Value));
}
private static List <IEnumerable <GeoCoordinate> > ParseCoordinateLists(WellKnownTextTokenizer tokenizer)
{
var coordinates = new List <IEnumerable <GeoCoordinate> >();
NextEmptyOrOpen(tokenizer);
coordinates.Add(ParseCoordinates(tokenizer));
while (NextCloserOrComma(tokenizer) == TokenType.Comma)
{
NextEmptyOrOpen(tokenizer);
coordinates.Add(ParseCoordinates(tokenizer));
}
return(coordinates);
}
private static MultiPolygonGeoShape ParseMultiPolygon(WellKnownTextTokenizer tokenizer)
{
if (NextEmptyOrOpen(tokenizer) == TokenType.Word)
{
return(null);
}
var coordinates = new List <IEnumerable <IEnumerable <GeoCoordinate> > >
{
ParseCoordinateLists(tokenizer)
};
while (NextCloserOrComma(tokenizer) == TokenType.Comma)
{
coordinates.Add(ParseCoordinateLists(tokenizer));
}
return(new MultiPolygonGeoShape(coordinates));
}
private static double NextNumber(WellKnownTextTokenizer tokenizer)
{
if (tokenizer.NextToken() == TokenType.Number)
{
if (string.Equals(tokenizer.TokenValue, WellKnownTextTokenizer.NaN, StringComparison.OrdinalIgnoreCase))
{
return(double.NaN);
}
if (double.TryParse(
tokenizer.TokenValue,
NumberStyles.AllowDecimalPoint | NumberStyles.AllowLeadingSign,
CultureInfo.InvariantCulture, out var d))
{
return(d);
}
}
throw new GeoWKTException(
$"Expected number but found: {tokenizer.TokenString()}", tokenizer.LineNumber, tokenizer.Position);
}
private static GeometryCollection ParseGeometryCollection(WellKnownTextTokenizer tokenizer)
{
if (NextEmptyOrOpen(tokenizer) == TokenType.Word)
{
return(null);
}
var geometries = new List <IGeoShape>
{
Read(tokenizer, GeoShapeType.GeometryCollection)
};
while (NextCloserOrComma(tokenizer) == TokenType.Comma)
{
geometries.Add(Read(tokenizer, null));
}
return(new GeometryCollection {
Geometries = geometries
});
}
private static EnvelopeGeoShape ParseBoundingBox(WellKnownTextTokenizer tokenizer)
{
if (NextEmptyOrOpen(tokenizer) == TokenType.Word)
{
return(null);
}
var minLon = NextNumber(tokenizer);
NextComma(tokenizer);
var maxLon = NextNumber(tokenizer);
NextComma(tokenizer);
var maxLat = NextNumber(tokenizer);
NextComma(tokenizer);
var minLat = NextNumber(tokenizer);
NextCloser(tokenizer);
return(new EnvelopeGeoShape(new[] { new GeoCoordinate(maxLat, minLon), new GeoCoordinate(minLat, maxLon) }));
}
private static bool IsNumberNext(WellKnownTextTokenizer tokenizer)
{
var token = tokenizer.PeekToken();
return(token == TokenType.Number);
}
private static IGeoShape Read(WellKnownTextTokenizer tokenizer, string shapeType)
{
var token = tokenizer.NextToken();
if (token != TokenType.Word)
{
throw new GeoWKTException(
$"Expected word but found {tokenizer.TokenString()}", tokenizer.LineNumber, tokenizer.Position);
}
var type = tokenizer.TokenValue.ToUpperInvariant();
if (shapeType != null && shapeType != GeoShapeType.GeometryCollection && type != shapeType)
{
throw new GeoWKTException($"Expected geometry type {shapeType} but found {type}");
}
switch (type)
{
case GeoShapeType.Point:
var point = ParsePoint(tokenizer);
point.Format = GeoShapeFormat.WellKnownText;
return(point);
case GeoShapeType.MultiPoint:
var multiPoint = ParseMultiPoint(tokenizer);
multiPoint.Format = GeoShapeFormat.WellKnownText;
return(multiPoint);
case GeoShapeType.LineString:
var lineString = ParseLineString(tokenizer);
lineString.Format = GeoShapeFormat.WellKnownText;
return(lineString);
case GeoShapeType.MultiLineString:
var multiLineString = ParseMultiLineString(tokenizer);
multiLineString.Format = GeoShapeFormat.WellKnownText;
return(multiLineString);
case GeoShapeType.Polygon:
var polygon = ParsePolygon(tokenizer);
polygon.Format = GeoShapeFormat.WellKnownText;
return(polygon);
case GeoShapeType.MultiPolygon:
var multiPolygon = ParseMultiPolygon(tokenizer);
multiPolygon.Format = GeoShapeFormat.WellKnownText;
return(multiPolygon);
case GeoShapeType.BoundingBox:
var envelope = ParseBoundingBox(tokenizer);
envelope.Format = GeoShapeFormat.WellKnownText;
return(envelope);
case GeoShapeType.GeometryCollection:
var geometryCollection = ParseGeometryCollection(tokenizer);
geometryCollection.Format = GeoShapeFormat.WellKnownText;
return(geometryCollection);
default:
throw new GeoWKTException($"Unknown geometry type: {type}");
}
}
/// <summary>
/// Reads Well-Known Text (WKT) into a new instance of <see cref="IGeoShape" />
/// </summary>
public static IGeoShape Read(string wellKnownText)
{
using (var tokenizer = new WellKnownTextTokenizer(new StringReader(wellKnownText)))
return(Read(tokenizer, null));
}
