Sunday, February 14, 2010

Progressive display of electronic documents

Faster networks, such as Google's 1 G fibre to the home trial, will not necessarily produce a better Internet service. I suggest we need to design electronic documents, including web pages and videos, to display just what the user needs at a particular time. A by-product of this is that will allow a slower network to be used and allow networks to cope with congestion and faults better.

Providing more data to the user will not necessarily provide more information, it may just increase confusion with irrelevant details. For education, it is often better to provide a simple schematic diagram, rather than a high resolution image. Pushing data on students does not help them. The e-learning materials for my 120 hour "Green Technology Strategies" course consist of only a few hundred kilobytes of data. There are gigabytes of extra readings, audio and video, but the essentials are a the equivalent of 100 pages of text. Even that is provided to the students, progressively over 12 weeks. I asked the students if they would like all the material at once at the beginning, so they could read ahead, but most said they preferred it week by week. Other materials are provided so the students can explore them, when the feel the need. In education-speak this is "mentored and collaborative learning", with some aspects similar to the Montessori method. It is not providing large amounts of information which are important in these learning techniques, but that materials and people, are to hand when needed. One of the educational areas which further work is in teaching students how to cope with an overload of information.

Similarly in medicine, irrelevant detail does not necessarily help. My doctor does not look at the detailed imaging provided by MRI, CAT, ultrasound and other scans. They read the brief text reports prepared from these by specialists. It might make me feel better if they were to examine these in a 3D system and draw circles around areas using a light pen, but it would not improve the medicine delivered.

This can also apply with web pages. Providing a large complex document can overwhelm the reader, whereas a simple introduction and set of links to details can ease them into the topic.

One application where progressive display can help is with smart phones. These devices have small screens, slower links and distracted users. So providing large amounts of material does not help technically nor for the user. The current approach is to create special applications and documents for mobile users. I suggest we can redesign web documents to automatically allow for this.

One simple case is web images. The common web image formats (GIF, PNG and JPEG) all now allow for progressive image display. That is the image file is created so that a low resolution version can be displayed first, increasing in detail as more data is provided. These formats could be used by smarter web browsers to display images in the appropriate resolution for the display device and available bandwidth. Web servers can automatically convert images to progressive formats as required.

Another progressive technique is in the creation of web pages. Web designed web pages and web site allow the user to get an introduction and overview and then select more details. Most web pages will begin to render before all data has arrived. If the important information is at the top of the page, the user can select a menu option without waiting for the rest. The same can be done with some PDF documents. This can't be done with most ebook formats and you have to wait for the whole ebook to download before you can read any of it.

Some new video formats similarly allow lower resolution previews and streaming of the start of the video, without having to wait for it all.

These techniques could make the slower networks most of us will have for the foreseeable future more usable, without having to wait for gigabit networks. Even with gigabit networks, being able to get just the information you need will be a boon, without being overwhelmed with data.

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