MultiPolygon.parseCoords constructor

MultiPolygon.parseCoords(Iterable<Iterable<String>> polygons, { Pattern delimiter = ',', Coords type = Coords.xy, bool swapXY = false, bool singlePrecision = false, })

Parses a multi polygon geometry from polygons with each polygon containing rings that are formatted as texts (with coordinate values separated by delimiter).

Use the required optional type to explicitely set the coordinate type.

If swapXY is true, then swaps x and y for all positions in the result.

If singlePrecision is true, then coordinate values of positions are stored in Float32List instead of the Float64List (default).

Examples:

// a multi polygon with one polygon from 2D positions
MultiPolygon.parseCoords(
  [
    // polygon
    [
      // an exterior ring with values of five (x, y) positions
      '10.0,20.0,'
      '12.5,22.5,'
      '15.0,25.0,'
      '11.5,27.5,'
      '10.0,20.0'
    ],
  ],
  type: Coords.xy,
);

// a multi polygon with one polygon from 3D positions
MultiPolygon.parseCoords(
  [
    // polygon
    [
      // an exterior ring with values of five (x, y, z) positions
      '10.0,20.0,30.0,'
      '12.5,22.5,32.5,'
      '15.0,25.0,35.0,'
      '11.5,27.5,37.5,'
      '10.0,20.0,30.0'
    ],
  ],
  type: Coords.xyz,
);

// a multi polygon with one polygon from 2D positions using an
// alternative delimiter
MultiPolygon.parseCoords(
  [
    // polygon
    [
      // an exterior ring with values of five (x, y) positions
      '10.0;20.0;'
      '12.5;22.5;'
      '15.0;25.0;'
      '11.5;27.5;'
      '10.0;20.0'
    ],
  ],
  type: Coords.xy,
  delimiter: ';',
),

// a multi polygon with one polygon from 2D positions with x before y
MultiPolygon.parseCoords(
  [
    // polygon
    [
      // an exterior ring with values of five (x, y) positions
      '20.0,10.0,'
      '22.5,12.5,'
      '25.0,15.0,'
      '27.5,11.5,'
      '20.0,10.0'
    ],
  ],
  type: Coords.xy,
  swapXY: true,
);

// a multi polygon with one polygon from 2D positions with the
// internal storage using single precision floating point numbers
// (`Float32List` in this case)
MultiPolygon.parseCoords(
  [
    // polygon
    [
      // an exterior ring with values of five (x, y) positions
      '10.0,20.0,'
      '12.5,22.5,'
      '15.0,25.0,'
      '11.5,27.5,'
      '10.0,20.0'
    ],
  ],
  type: Coords.xy,
  singlePrecision: true,
);

Implementation

factory MultiPolygon.parseCoords(
  Iterable<Iterable<String>> polygons, {
  Pattern delimiter = ',',
  Coords type = Coords.xy,
  bool swapXY = false,
  bool singlePrecision = false,
}) {
  if (polygons.isEmpty) {
    return MultiPolygon.build(const []);
  } else {
    return MultiPolygon(
      polygons
          .map(
            (polygon) => polygon
                .map(
                  (ring) => parsePositionSeriesFromTextDim1(
                    ring,
                    delimiter: delimiter,
                    type: type,
                    swapXY: swapXY,
                    singlePrecision: singlePrecision,
                  ),
                )
                .toList(growable: false),
          )
          .toList(growable: false),
    );
  }
}