Release Notes

JViews 4.0 Maps Release Notes

This document describes the main changes that have been made to the JViews Maps module since version 3.5.

General Changes
Library Changes
       New Classes and Interfaces

  • maps.IlvLookAheadFeatureIterator
  • maps.format.IlvMapTileLoader
  • maps.format.shapefile.IlvShapeFileIndex
  • maps.format.shapefile.IlvShapeFileTileLoader
  • maps.format.shapefile.IlvShapeFileSpatialIndex
  •       Modified Classes Demonstration Changes


    General Changes

    Support for load-on-demand on ESRI Shapefiles has been added. To load Shapefiles on demand, a new type of file, with the .idx extension, has been introduced. These files contain the spatial indexes associated with Shapefiles.
    The following classes have been added to support the load-on-demand feature: A new class has been added to simplify the creation of tile loaders: the IlvMapTileLoader class. This class includes all standard rendering features and tile loading for all tile loaders.


    Library Changes

    New Classes and Interfaces
    New Interfaces
    ilog.views.maps.IlvLookAheadFeatureIterator
    Defines the interface for IlvMapFeatureIterator that has the ability to fetch the ID of the next feature before reading it, allowing you to skip the next feature if it is not needed.
    New Classes
    ilog.views.maps.format.IlvMapTileLoader
    This abstract class proposes a default implementation of an IlvTileLoader. This implementation has a load() method that can take advantage of IlvLookAheadFeatureIterators. Tile loaders that use this class as the base class have only a few methods to implement.
    ilog.views.maps.format.shapefile.IlvShapeFileIndex
    This class brings the support of ESRI Shapefile index files (.shx extension). Shapefile index files provide file offset information for random access of geometries in a Shapefile geometry file (.shp).
    ilog.views.maps.format.shapefile.IlvShapeFileTileLoader
    This class is an IlvMapTileLoader specialized in reading tiles from a Shapefile. This class provides IlvLookAheadFeatureIterator to load from Shapefile tiles, and thus can be exploited by the load() method of IlvMapTileLoader.
    ilog.views.maps.format.shapefile.IlvShapeFileSpatialIndex
    This class stores the spatial information of Shapefiles. Basically, for each tile corresponding to the Shapefile, this class stores the IDs of the geometries, thereby enabling the load-on-demand feature.
    The spatial index can be saved as an .idx file to allow load-on-demand without the need to rebuild the spatial index each time.
    Modified Classes

    ilog.views.maps.format.shapefile.IlvDBFReader

    ilog.views.maps.format.shapefile.IlvSHPReader ilog.views.maps.format.shapefile.IlvShapeFileReader


    Demonstration Changes

    The ESRI Shapefile demos

    A new demo has been added in the <installdir>/demos/maps/esri directory. This demo is the LODViewer. It contains sample code to create a load-on-demand layer for Shapefiles. You can also use it to create the spatial index for Shapefiles that do not have one.
    To view a Shapefile in load-on-demand:

    To create the spatial index for a Shapefile: