Pregenerating tiled images for a thin client

The IlvManagerTiler class is a utility class that renders a map, saved to a specified location on the disk at different scale levels, as tiled images. These images can be used to fill the cache of a thin-client server application. Offline tile generation speeds up the initial response time of the server, as it does not need to create and cache the images when clients request them. It increases the server scalability for the same reason.

The first step to generate tiled images for a map is to ensure that the Thin Client Parameters have been set in the map, see Setting Thin Client Parameters in JViews Maps Using the Map Builder. What the map builder does is that is to add two IlvNamedProperty instances to the map. The names of these properties are defined in the IlvMapTileGen IlvMapTileGeneratorConstants class as constants:

If these parameters are not set in the map, you must specify them explicitly in the createTiles() method call. Then, you must create an IlvManagerTiler instance and call the createTiles method with the appropriate parameters using the following code:

IlvManagerTiler tiler = new IlvManagerTiler();
long maximumDiskSpace = 10000000; // 10 Mbytes
String mapFilename = "MyMap.ivl";
File outputFolder = new File("output");
tiler.createTiles(mapFilename,null, outputFolder, maximumDiskSpace);
// Null is passed as the region so as not to limit the tiling process.

Remember that generating tiles for a map covering a large region, with several scale levels, and without specifying an area of interest, can easily lead to millions of tiles being created. This may require several Gigabytes of memory and in some cases may take a long time to complete.

To avoid this:

A graphical tool to interactively generate tiles is provided as a code sample in: <installdir> /jviews-maps810/samples/tilegeneration/src/TileGenerator.java.