PolygonAreaVB - sindizzy/DSW GitHub Wiki

Sample code demonstrating how to calculate the area of a polygon.

Imports DotSpatial.Geometries
Imports DotSpatial.Topology.Geometries

Private Sub btnArea_Click(sender As Object, e As EventArgs)
	Try
		'Creates a new array of coordinates
		Dim coords As Coordinate() = New Coordinate(19) {}
		'Creates a random number generator
		Dim rnd As New Random()
		'Createa a center point for the polygon
		Dim center As New Coordinate((rnd.NextDouble() * 360) - 180, (rnd.NextDouble() * 180) - 90)
		'A For Loop that will randomly create coordinates and feeds the coordinates into the array of coordiantes
		For i As Integer = 0 To 18
			coords(i) = New Coordinate(center.X + Math.Cos((i * 10) * Math.PI / 10), center.Y + (i * 10) * Math.PI / 10)
		Next
		'Set the last coordinate equal to the first coordinate in the array, thus 'closing' the polygon
		coords(19) = New Coordinate(coords(0).X, coords(0).Y)
		'Creates a new polygon from the coordinate array
		Dim pg As New Polygon(coords)
		'Determines that area of the polygon
		Dim area As [Double](Double) = pg.Area
	Catch ex As Exception
		MessageBox.Show(ex.Message)
	End Try
End Sub