The WkbDataLayer class provides access to spatial and attribute data stored in a general-purpose database (such as Access).

Namespace: ActualMap.Data
Assembly: ActualMap (in ActualMap.dll)


Visual Basic (Declaration)
Public Class WkbDataLayer
    Inherits SpatialDatabaseLayer
public class WkbDataLayer : SpatialDatabaseLayer
ref class WkbDataLayer : SpatialDatabaseLayer
public class WkbDataLayer extends SpatialDatabaseLayer
public class WkbDataLayer extends SpatialDatabaseLayer


This class supports shapes stored in BLOB (binary large object) fields. The internal structure of shapes must conform to the OpenGIS Well-Known Binary (WKB) format.

The FieldList property should be specified if attribute data from the database is necessary (for labeling, quering, or editing purposes).

The extent of database layers is not calculated automatically for performance reasons. If you use only database layers in your application, you should set the Extent property before adding the layer to the map.

By default, the extent of database layers is set to (-180,90,180,-90) (units are decimal degrees). The coordinate system is set to WGS 1984 (EPSG/SRID code is 4326).

This class does not support spatial indexes and using it for large databases can affect performance.

Inheritance Hierarchy


Thread Safety

Public static (Shared in Visual Basic)staticShared members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

See Also