WebÞing

Note: if you have used an automatic installer, you can probably ignore this document and just run the software.

Using the HyperDAAC

Please ensure you have a working JAVA 1.1 environment before using the HyperDAAC. Note that JAVA support in your web browser does not necessarily mean you have it available for applications, although modern versions of many operating systems include JAVA support. If you need to install JAVA, please see here.

Running the software is simple: set your CLASSPATH and run the class webthing.daactools.launcher on a HyperLens Definition (.hld) file. CLASSPATH must include:

  1. hldaac.jar - HyperLens® viewer software with additional HyperDAAC tools.
  2. hjb.jar - HotJavaTM (web browser) software.
  3. The CDROM itself (HyperLens uses CLASSPATH to locate the data products).

It is also strongly recommended that you allocate somewhere on your hard disc (directory, folder, or equivalent) for scenes generated by HyperLens®. You should then run HyperLens® from there, so that it appears immediately when you open a dialogue box to load or save a file.

Examples

  1. A user xyz on a Unix system with CDROM mounted at /cdrom and work area /home/xyz/hyperdaac might use the following command:
    cd /home/xyz/hyperdaac; jre -cp "/cdrom:/cdrom/hldaac.jar:/cdrom/hjb.jar" webthing.daactools.launcher /daac/defn64.hld
    or, more conveniently, a startup script: 
    #!/bin/sh
export CLASSPATH="/cdrom:/cdrom/hldaac.jar:/cdrom/hjb.jar:$CLASSPATH"
cd $HOME/hyperdaac
jre webthing.daactools.launcher /daac/defn64.hld

    This script could equally be installed by a UNIX system administrator to make the HyperDAAC available to all users on the system or (if you have a Site License) network.

     

  2. A Windows 9x system with CDROM on D: and work area C:\hyperdaac might use 

    cd C:\hyperdaac; jre -cp D:\ -cp D:\hldaac.jar -cp D:\hjb.jar webthing.daactools.launcher /daac/defn64.hld

Both the above will open the 64Km whole-world browse scene. To use the 32Km scene, just substitute 32 for 64 in the above. Bear in mind that the 32Km image is rather large (1250 by 542 pixels) and may display slower, particularly if you use several large lenses.

Once you have created new scenes, you can open them directly. Scenes created using the HyperDAAC tools or the HyperLens® editor will have the suffix .hld (HyperLens Definition). 

jre webthing.daactools.launcher something.hld

You can also open any existing scene within HyperLens®, using the File menu.

Working with large Images

The HyperDAAC is designed to facilitate extracting a small area of interest at a suitable spatial resolution, so that you don't have to work with large images. If you do want to load larger images, you will need to allocate more memory to JAVA. You can do that using the commandline. For example 

jre -mx32m webthing.daactools.launcher myscene.hld
permits JAVA to use 32Mb memory, which is sufficient to work with a whole-world scene at 16Km (2501x1085 pixels). In principle this is unlimited: we have (occasionally) used 64Mb for HyperLens®. If you are fortunate to have 384Mb RAM and 768Mb swap, you can (try) allocating 1Gb to JAVA - but expect slow performance!

See also