topic Re: Creating Buffer for a Poly-line feature in ArcObjects SDK Questions

Creating Buffer for a Poly-line feature

BinodKumar — Thu, 22 Jul 2010 06:10:14 GMT

Hi,

I m using ADF in web based application using asp.net/c#.There is requirement to create a buffer around a poly-line feature.
Can anyone suggest a way in which we can accomplish this.

thanks in advance

Re: Creating Buffer for a Poly-line feature

spiskulaspiskula — Thu, 22 Jul 2010 08:16:14 GMT

how about using class BufferConstruction and IBufferConstructionProperties ?

Re: Creating Buffer for a Poly-line feature

BinodKumar — Thu, 22 Jul 2010 08:55:16 GMT

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);
}

Re: Creating Buffer for a Poly-line feature

PhilBlondin — Tue, 27 Jul 2010 17:13:55 GMT

The below vb function will buffer a polyline. If your distance units are in a coordinate system which uses meters then you will have to convert the units or project the polyline into footage coordinate system.

pPL.SpatialReference = yoursourcespatialreference
pPL.Project yournewcoordinatesystem

Public Function BufferRoute(pPL As IPolyline, dBuffDistance As Double) As IPolygon

    Dim pTopoOp As ITopologicalOperator3
    Dim pPoly As IPolygon
    Set pTopoOp = pPL
    Set pPoly = pTopoOp.Buffer(dBuffDistance)

    Set BufferRoute = pPoly

    Set pPL = Nothing
    Set pTopoOp = Nothing
    Set pPoly = Nothing

End Function