I found this code from net but i m not getting what exactly i need to do there for the bold line below "spatial reference should be set here "
[C#]//This example demonstrates how to use ITopologicalOperator::Buffer
private void BufferArea()
{
IPoint[] points = new IPoint[5];
//The spatial reference should be set here using IGeometry::SpatialReference (Code skipped here)
for(int i = 0; i < points.Length; i++)
{
points = new PointClass();
}
points[0].PutCoords(0, 0);
points[1].PutCoords(0, 10);
points[2].PutCoords(10, 10);
points[3].PutCoords(10, 0);
points[4].PutCoords(0, 0);
IPointCollection4 pointCollection = new PolygonClass();
IGeometryBridge geometryBride = new GeometryEnvironmentClass();
geometryBride.AddPoints(pointCollection, ref points);
IArea area = pointCollection as IArea;
System.Windows.Forms.MessageBox.Show("Area original polygon : " + area.Area);
ITopologicalOperator topologicalOperator = pointCollection as ITopologicalOperator;
//Outside buffer
IPolygon polygon = topologicalOperator.Buffer(1) as IPolygon;
area = polygon as IArea;
System.Windows.Forms.MessageBox.Show( "Area polygon positive distance : " + area.Area);
//Inside buffer
polygon = topologicalOperator.Buffer(-1) as IPolygon;
area = polygon as IArea;
System.Windows.Forms.MessageBox.Show("Area polygon negative distance : " + area.Area);
}
