New and Changed Features

This section describes major features that are new or changed since the previous release of MapViewer, which was included in Oracle9iAS Release 2 (9.0.2 and 9.0.3).

Java Client API

A new Java client API provides convenient access to most MapViewer functions from a Java application, a Java applet, a servlet within a Java2 Enterprise Edition (J2EE) container different from the J2EE container that contains the MapViewer service, or JavaServer Pages (JSP) code within the J2EE container that contains the MapViewer service. For information about the JavaBean-based API, see Chapter 4.

JSP Tag Library

A set of custom JSP tags can be used to develop JSP applications using MapViewer features. The minimum version requirement for using this JSP tag library is Oracle9iAS release 9.0.3 or standalone OC4J release 9.0.3. For information about the MapViewer JSP tag library, see Chapter 5.

PNG Format Support

Maps can now be rendered into PNG format, which provides a richer representation media and faster creation time than the GIF format. The format attribute of the <map_request> element accepts the PNG_STREAM and PNG_URL values, as explained in Section 3.2.2.

Map Legend Support

Map legends are supported. The content and layout of a legend can be customized. For information about map legends, see Section 2.4.2.

Query Capabilities with Nonspatial Attributes

A set of methods is provided for querying nonspatial attributes based on locations. See Section 4.3.8 for details.

Basic Support for Georeferenced Images

You can define image themes that can be rendered along with the normal vector themes. By default, MapViewer supports JPEG formatted images, but other formats can be supported through a custom image renderer interface. For information about image themes, see Section 2.3.4. For information about creating and registering a custom image renderer, see Appendix B.

JDK 1.4 and AWT Headless Mode Support

MapViewer can now be run in the JDK 1.4 Java virtual machine (JVM). MapViewer also supports the new headless AWT mechanism in JDK 1.4, which enables MapViewer to run on Linux or UNIX systems without setting any X11 DISPLAY variable. To enable AWT headless mode on Linux or UNIX systems, specify the following in the command line to start MapViewer:

-Djava.awt.headless=true

Performance Improvements

The performance of MapViewer has been improved, particularly in querying and retrieving spatial data.

You may also be able to improve performance further by customizing the spatial geometry data cache, as explained in Section 1.5.6.