Accessibility - How to Navigate this Site
Structure
The site is designed in a hierarchical manner. The first level is the home page which has links to a series of pages which introduce the following topics.
Note the keystrokes for accessing the Accessibility Page. These apply for all the pages on the site.
Note Alt + A means press the alt button and the A button together, don't include the + key.
These links lead to the Introduction pages for each topic. They give a brief overview of the subject before leading on to a page with more options. On the left hand side is an image map menu which will appear on the majority of pages on the site.
It has four visible links
Note the key strokes. Again you may have to hit enter after these key strokes depending on your browser. My version of Internet Explorer (6.0) requires an enter stroke whilst Firefox does not as it jumps straight to the required page as does Netscape (7.1). Unfortunately Netscape (4.0) and Opera ignores access keys altogether. I have placed a "Bio-diversity" page between the levels which does not strictly adhere to the structure but it acts as a "catch all" page for the natural history topics and makes navigation simpler allowing me to eliminate a lot of repetitive links.
The following links are not visible but can be accessed by key strokes.
Skip to main content allows users of screen readers to skip the menu and go straight to the information in the pages. These invisible links are available on every page along with the Home - Alt + H link regardless of any other navigation aid which may be present.
It is possible to tab through these invisible links and the image map menu. They will always be at the beginning of the page and are indexed to work before any other links on the page.
At the bottom of each Introduction Pages is a large graphic arrow sending you to the subject page with various options available.
At this point the structure starts to become linear, particularly with the History and Geology sections as the information they contain is more "story like" than with the natural history topics.
The core of the information in the natural history parts of the site is found in the "Guides". Where there is a lot of information there will be a link from the Guide Page to "More Information" should your interest take you there. Associated with these subjects are a few lists, search pages and picture galleries. It is here that the use of the image map navigation became unsuitable and alternative means of navigation are used. The invisible key strokes are always available and there is always a link to the home page and the site map plus the ever useful back button.
All tables whether they are for data or positioning have a summary explaining what is in them.
I have set the font size to provide as wide a useable size range as possible in Internet Explorer with its limited capabilities. The better browsers like Firefox and Netscape (7.1) with their zooming facility (Ctrl + +/-) function well.
The site also works with style sheets disabled although not quite so gracefully.
There is some scripting in the site but an alternative is available for users who turn scripts off. Where mouse over is used an alternative method is available for non mouse users.
At no point in the site will a page open in a new window. A tool tip type information system is used but all screens that open close automatically after a set period of time.
I have used Jaws as a screen reader to test this site and I have endevoured to make the spoken version as intelligeable as possible. I have tried to eliminate where possible repetative or redundant information in "alt" text and "titles". I do not have other screen readers available for testing purposes so I have to hope that they act in similar ways.
I have used "Bobby" to test the accessibility of the site and in the main it conforms