ArcObjects Library Reference (Display)

IMarkerPlacement Interface

Provides access to members that control the marker placement.

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.

When To Use

This interface must be implemented by all custom marker placement objects along with IGraphicAttributes and IPersistVariant interfaces (or IPersist and IPersistStream in Visual Basic 6.0).

Members

		Description
	AcceptGeometryType	Indicates if the input geometry type is valid.
	NextTransformation	Hands back the next transformation.
	Reset	Resets the collection of transformations. Must be called before using NextTransformation.

CoClasses that implement IMarkerPlacement

CoClasses and Classes	Description
MarkerPlacementAlongLine	Places markers along a line.
MarkerPlacementAtExtremities	Places a marker on each extremity of a line.
MarkerPlacementDecoration	Places markers as line decorations.
MarkerPlacementInsidePolygon	Places markers in a polygon.
MarkerPlacementOnLine	Places one marker along a line.
MarkerPlacementOnPoint	Places a marker on a point.
MarkerPlacementOnVertices	Places markers on curve vertices.
MarkerPlacementPolygonCenter	Places one marker at the center of a polygon.
MarkerPlacementRandomAlongLine	Places markers randomly along a line.
MarkerPlacementRandomInPolygon	Places markers randomly within a polygon.
MarkerPlacementVariableAlongLine	Places markers with variable size along a line.

Remarks

Use IMarkerPlacement to define how you want to place marker symbols with respect to input geometry. If you create a custom marker placement, then IGraphicAttributes interface which will define the properties for this effect and IPersistVariant (VB users) or IPersist and IPersistStream (C++ users) to persist the object have to be implemented.

AcceptGeometryType is a boolean that indicates if the input geometry type is valid for the MarkerPlacement object. For example, this property returns True if input is esriGeometryPoint for MarkerPlacementOnPoint as this object places a marker at the location of the point geometry.

Reset method is used to re-set the result of applying a marker placement to a feature representation. Next method is used to retrieve the individual transformations created after the marker placement is applied. Sometimes a placement style may result in a multi-point output transformations. For example, MarkerPlacemementAlongLine places multiple markers along a line geometry.

Note: Reset method has to be called prior to calling Next method.

To make changes to an existing BasicMarkerSymbol's marker placement property use IBasicMarkerSymbol::MarkerPlacement property to retrieve the object and make changes using a IMarkerPlacement interface.