Frequently Asked Questions

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The Helioviewer Project

What is The Helioviewer Project?

It's a suite of (mostly) open technologies designed to make populous archives of large images and related data and metadata available over the web, via intuitive interfaces. It grew out of solar physics, where there is a need to be able to visualize large numbers of heterogeneous data-sets that observe phenomena in the inner heliosphere. The interfaces we have developed are designed to let users overlay multiple data-sets and enable exploration on user-defined time-scales and length-scales.

What is the relation of the Helioviewer Project to Helioviewer.org and JHelioviewer?

The web application, Helioviewer.org, and the downloadable application, JHelioviewer, are the two browse clients we have developed to interface with our image and feature/event services. The two clients communicate with the same image and feature/event databases, share much of the same technology on the back-end, and have many similar features in their user interfaces. The similarities and differences between each of these clients is discussed below.

Helioviewer.org and JHelioviewer seem rather similar. Why have both?

It is true that the two browse clients do offer very similar functionality. However, they do differ in some important respects. Helioviewer.org does not require any installation (only a compatible web browser) and everyone will get the exact same functionality as soon as upgrades are available. It also works - to some extent - on mobile platforms, such as the iPhone/Safari. On the other hand, JHelioviewer enables interactive streaming of images and movies at variable resolution and quality using our JPIP server. JHelioviewer can also perform basic image processing (e.g. apply a color table, gamma correction or sharpening) on the fly. Using Java Web Start, code updates are automatically downloaded.

Our goal is to enable the exploration of solar and heliospheric data, and so by developing multiple clients, we give the user the ability to choose the interface they prefer. The source code for both clients is open, so if you have any improvements, please let us know.

JPEG2000

What is JPEG2000?

JPEG 2000 is a relatively new standard for the encoding of images. It is based on a wavelet encoding of the original image. The JPEG 2000 standard offer many advantages over more widely adopted and current image compression standards such as JPEG and PNG.

For much more information, please consult:

If it's so great, why isn't it everywhere on the web?

The lack of native browser support for displaying JPEG2000 images is one reason. There is also a dearth of freely available compression/decompression tools. Also, JPEG2000 is really good for looking at very big images over the web. Most people compress their images somewhat so that they are a manageable size i.e., they don't take too long to upload or download. That's ok for looking at photographs, but for something approaching science quality, you need access to large images at very good quality.

So why did you choose it as the basis of the Helioviewer Project?

Two main reasons:

  1. Firstly, it is a very good archive format, as it allows you to compress once, but decompress in many different ways - which allows you to generate subfield images and zoom-in/out very easily.
  2. Secondly, the JPEG2000 standard contains JPIP, the JPEG2000 Interactive Protocol (see below), that allows you to easily transfer over the web, only the information you are interested in. This means you don't have to download the whole image in order to see the much smaller bit you are interested in.

Helioviewer.org

What is Helioviewer.org?

It is a web application to enable the exploration of heterogeneous solar and heliospheric data-sets. It is an interface to the image and feature/event services of the Helioviewer Project.

Where can I get it?

Go to www.helioviewer.org. You can download the source code here.

What does it do?

It allows you to visualize multiple observations of the Sun and inner heliosphere at the length-scales and time-scales you are interested in, from your web browser - no need to download anything. Much more information on using Helioviewer.org can be found here.

Something doesn't work - how do I report a bug?

Please report bugs here.

JHelioviewer

What is JHelioviewer?

JHelioviewer is a Java application for visualizing and exploring heterogeneous solar and heliospheric data-sets. It is an interface to the image and feature/event services of the Helioviewer Project.

Where can I get it?

Go to www.jhelioviewer.org to download the latest version. You can download the source code here.

What does it do?

It allows you to visualize images and movies of the Sun and inner heliosphere at the length-scales and time-scales you are interested in. It communicates with our JPIP server (see below) to enable image and movie streaming. Much more information on using JHelioviewer can be found here.

Something doesn't work - how do I report a bug?

Please report bugs here.

JPIP

What is JPIP?

JPIP is an acronym for the JPEG 2000 Interactive Protocol

What does it do?

I'm interested in this - where can I get your JPIP server?

Other

Is there anything else out there like the Helioviewer Project?

We keep a list of resources that have overlapping interests with the Helioviewer Project. us know if you find something that should be on this list.

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