﻿ ConstructPolygonsFromPolylines Method (GeometryEngine)—ArcGIS Pro
ArcGIS Pro 3.3 API Reference Guide
ArcGIS.Core.Geometry Namespace / GeometryEngine Class / ConstructPolygonsFromPolylines Method
The set of polylines to create polygons from. If a polyline has curves, a densified copy of it is used to construct the polygons.
Example

In This Topic
ConstructPolygonsFromPolylines Method (GeometryEngine)
In This Topic
Generates polygons from a set of polylines.
Syntax
```public IReadOnlyList<Polygon> ConstructPolygonsFromPolylines(
IEnumerable<Polyline> polylines
)```
```Public Function ConstructPolygonsFromPolylines( _
ByVal polylines As IEnumerable(Of Polyline) _
) As IReadOnlyList(Of Polygon)```

#### Parameters

polylines
The set of polylines to create polygons from. If a polyline has curves, a densified copy of it is used to construct the polygons.

#### Return Value

Returns the polygons. If none are created, then the collection returned is empty.
Exceptions
ExceptionDescription
The polylines is null.
Remarks
The polylines may cross rather than be connected from end to end.

Example
Construct a Polygon from a set of Polylines
```List<Coordinate2D> firstLinePts = new List<Coordinate2D>();
firstLinePts.Add(new Coordinate2D(1.0, 1.0));
firstLinePts.Add(new Coordinate2D(1.0, 4.0));

List<Coordinate2D> secondLinePts = new List<Coordinate2D>();
secondLinePts.Add(new Coordinate2D(4.0, 4.0));
secondLinePts.Add(new Coordinate2D(4.0, 1.0));

List<Coordinate2D> thirdLinePts = new List<Coordinate2D>();
thirdLinePts.Add(new Coordinate2D(0.0, 2.0));
thirdLinePts.Add(new Coordinate2D(5.0, 2.0));

List<Coordinate2D> fourthLinePts = new List<Coordinate2D>();
fourthLinePts.Add(new Coordinate2D(0.0, 3.0));
fourthLinePts.Add(new Coordinate2D(5.0, 3.0));

// build the polylines
List<Polyline> polylines = new List<Polyline>();
polylines.Add(PolylineBuilderEx.CreatePolyline(firstLinePts));
polylines.Add(PolylineBuilderEx.CreatePolyline(secondLinePts));
polylines.Add(PolylineBuilderEx.CreatePolyline(thirdLinePts));
polylines.Add(PolylineBuilderEx.CreatePolyline(fourthLinePts));

// construct polygons from the polylines
var polygons = GeometryEngine.Instance.ConstructPolygonsFromPolylines(polylines);

// polygons.Count = 1
// polygon coordinates are (1.0, 2.0), (1.0, 3.0), (4.0, 3.0), (4.0, 2.0)
```
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also