The USRP reader

Defense > Programmer's documentation > Programming with JViews Maps for Defense > Readers and writers > The USRP reader

The USRP reader

Describes the USRP reader provided.

Overview

Provides packaging and general information for the USRP reader.

The IlvRasterUSRPReader class

Describes the characteristics of the IlvRasterUSRPReader class.

Using the IlvRasterUSRPReader class to create images

Explains how to create the USRP reader, the data source and read the data to create images.

Overview

This package contains classes for reading UTM/UPS Standardized Raster Product (USRP) files. The USRP format (see DIGEST ASRP and USRP) is a map format for scanned maps that is published by the Digital Geographic Information Exchange Standard (DIGEST), see http://www.digest.org/.

The USRP readers provided by JViews Maps for Defense are based on specification document The UTM/UPS Standard Raster Product Specification: Edition 1.3, August 1997. A set of USRP files contains a single scanned map transformed to either a Universal Polar Stereographic (for polar regions) or a Universal Transverse Mercator (for the rest of the world) frame of reference.

The source code for the Map Builder demonstration, which contains all of the code described in this section, can be found at <installdir> /jviews-maps/samples/mapbuilder/index.html

The IlvRasterUSRPReader class

The IlvRasterUSRPReader class reads USRP images. It has the following characteristics:

It needs the USRP .IMG, .GEN and .QUA files to be able to parse bitmap data.

It implements the IlvMapFeatureIteratorinterface.

It can manage more than one image.

For each USRP image added, the reader returns one IlvMapFeature object, which is the geo-referenced image stored in the USRP files. The map feature has:

Geometry of type IlvMapImage.

Attributes created from the .QUA file metadata.

Using the IlvRasterUSRPReader class to create images

To create the IlvRasterUSRPReader:

Provide the name of the .GEN file describing the USRP image:

IlvRasterUSRPReader imageReader = new IlvRasterUSRPReader();

imageReader.addMap(fileName);

The reader removes the extension, that is, the characters after the last period ( . ) at the end of the filename, and constructs the names of the .GEN, .IMG and .QAL files from that base name. Note that a field inside the .GEN file can possibly override this default mechanism.

To create a data source and link it with the manager properties:

Define and insert the data source in the data source tree:

IlvMapDataSource imageDataSource =

IlvRasterDataSourceFactory.buildTiledImageDataSource(manager,imageReader,

true,true,null);

IlvMapDataSourceModel dataSourceModel =

IlvMapDataSourceProperty.GetMapDataSourceModel(manager);

dataSourceModel.insert(imageDataSource);

To start reading the data:

Start the data source:

dataSourceModel.start();

Starting the data source creates the necessary tiled layers, tile managers, and IlvRasterIcon instances to manage the pixel-on-demand feature and the progressive display of the geo-referenced image.

For further information, see:

Raster data sources, for defense-specific data sources.

Introducing the main classes and Creating a map application using the API for non defense-specific data sources, properties, tiling, and pixel-on-demand.