Provides access to members that buffer sets of geometries.
Product Availability
Description
This interface is new at ArcGIS 9.3.
Members
Description | ||
---|---|---|
Buffer | Compatibility method for clients wishing to replace useages of ITopologicalOperator::Buffer. This method does not use the properties exposed in IBufferConstructionProperties. | |
ConstructBuffers | Constructs buffer polygons at the specified distance for the set of input geometries. The input geometries can be a mix of polylines, polygons, points and multipoints. | |
ConstructBuffersByDistances | Constructs buffer polygons for the set of input geometries and distances supplied from the specified source-sink interface. The input geometries can be a mix of polylines, polygons, points and multipoints. | |
ConstructBuffersByDistances2 | Constructs buffer polygons for the set of input geometries and distances supplied from arrays. The input geometries can be a mix of polylines, polygons, points and multipoints. | |
EmptyBufferIDs | Returns an array of identifiers of input geometries that result in empty buffers - typically as a result of buffering polygons by negative distances. The identifier is either a sequence number or a geomID. |
CoClasses that implement IBufferConstruction
CoClasses and Classes | Description |
---|---|
BufferConstruction | Buffers collections of lines or collections of polygons. |
Remarks
The BufferConstruction object implements an updated, highly robust geometric buffering operation. It is designed to process a large number of inputs without requiring that all inputs and outputs exist in main memory at the same time. It provides additional buffering options that are not possible with the current ArcObjects Buffer method. For example, geodesic buffers can be generated around points. Finally, it provides a compatibility operation that lets clients of the existing Buffer operation use this object with a minimal impact on their existing code. In fact, the simplest way to use the buffer construction object is:
IBufferConstruction bc = new BufferConstruction()
Buffer = bc.Buffer(myInputGeometry, distance);
Overview of capabilities of the BufferConstruction
object
The IBufferConstructionProperties interface provides several new options for construction of geometric buffers:
Polyline buffers can be constructed to the left or the right of the polyline
Polygon buffers can exclude the interior of the polygon
Curve segments can be added to the output buffers
Buffers can be dissolved togther in places where they overlap
Seperate polygons can be generated for each non-overlapping portion of a buffer
True geodesic buffers can be generated around points that are in a geographic coordinate system
Geometries of different types can be buffered together
Multiple buffer offsets can be generated around the same set of inputs
In the context of a single buffering operation, different features can be buffered by different distances
The buffer construction object requires the use of
temporary files. They will be placed in the directory identified by
the pathname contained in the environment variable
ARCTMPDIR. If the variable does not exist, then
the system TEMP location will be used. Temporary files are removed
at the end of a buffer operation.
Buffering large sets of geometries and buffering
each input geometry with a different
distance
You can buffer large collections of geometries,
without staging either the inputs or the outputs in memory, by
implementing the IGeometricBufferSourceSink
interface and using the
ConstructBuffersByDistances method, or by implementing the
IEnumGeometry
and IGeometryCollection
interfaces and using the
ConstructBuffers method. Alternatively, you can directly use
geometry bags and double arrays with the ConstructBuffers method,
but then inputs and outputs must be staged in memory.
If you wish to apply a different buffer distance to
each input geometry, you can use the
ConstructBuffersByDistances2 method, which requires that inputs
and outputs be staged in memory first, or implement the
IGeometricBufferSourceSink interface and use the
IBufferConstruction::ConstructBuffersByDistances method.
If a client chooses to implement IEnumGeometry and
IGeometryCollection in conjunction with the ConstructBuffers
method, not all IEnumGeometry or IGeometryCollection methods need
to be implemented. Only the Next method on IEnumGeometry, and the
AddGeometry method on IGeometryCollection, are used by the
BufferConstruction object.