Monday, 14 April 2014

Proposal for an Open Educational Resource vector graphics library


Vector graphics can be used to illustrate learning materials in a variety of screen-based as well as print media. One of the main advantages of vector graphics is that they can be edited, restyled, broken apart and combined to suit many different purposes at any resolution. A collection of consistently-produced, open-licensed, open format vector graphics could form a component library that I believe would effectively complement an Open Educational Resource repository like Jorum or Re:Source.


Current Open Educational Resource repositories have the potential to revolutionise the creation of learning materials. However, some authors have reported difficulties in using current tools and technologies to produce the high-quality learning materials they can envisage. One area of difficulty might be in tools and resources for illustrating and diagramming, which often need technical and artistic skills, and/or expensive proprietary software, and/or result in graphic files that are difficult to combine, edit and reuse.

When I worked in learning materials production, we used vector applications like FreeHand and Illustrator, and we built up our own small libraries of vector components (symbols, components, equipment, charts) to reuse in future diagrams and illustrations. Perhaps something can be done across the sector, using open licences.


However, there are some issues that need to be addressed to allow authors, editors and other contributors to harness and build up such component libraries. When I was working on an online heraldic device generator, I was able to reuse fine examples of lions, eagles and dragons that others had created and released under open licences. Nevertheless, some significant reworking was needed to make the SVG compatible with my web application, primarily to allow for colour changes.

Some people might say, why not simply use existing clip art libraries, which often have collections of royalty-free vector graphics? There are a number of potential problems with these:

  1. The licensing may be unclear or restrictive, or the actual provenance of the graphics uncertain. To be a proper fit for an OER repository, graphics should have clear provenance and use the same (Creative Commons, probably) licences as the rest of the resources.
  2. Free clip art may be of dubious quality. Who could forget Microsoft's infamous globe with the poles in the wrong place, or clock with incorrect roman numerals? You may also get a surprise when trying to edit them, especially if they have been "flattened" (useful structure removed) or produced from line art by automated means.
  3. The clip art may be in so varied styles that combining them would be painful and/or unacceptable.
  4. The clip art may not form coherent or comprehensive collections that can be augmented as required.

Current environment for vector graphics

Current and recent versions of all major desktop (and most mobile) web browsers support the Scaleable Vector Graphic standard within HTML5 without need for plug-ins.

A range of SVG-supporting editing software, from the commercial Adobe Illustrator through the free Inkscape to the browser-based SVGedit are available.

Where vector graphics are not supported, they may be converted in bitmaps (rasterised) such as PNGs, which are used for the examples in this blog post. The original vector (such as SVG or Illustrator) files should always be supplied with the OER materials to allow editing.

Suggested specifications and technologies

Each vector graphic would be editable, repurposeable, restyleable, possibly with interchangeable components. They could be combined or taken apart to form new graphics. They would have consistent, semantic metadata and build up into collections.

  1. There would be one or more distinct illustrative styles, such as symbolic, realistic, cartoon and so forth.
  2. Each graphic would probably have a silhouette, which could be used as an outline (useful for infographics) or shadow.
  3. Technologies: probably be SVG with CSS for styling. A standardized system of CSS classes should make styling easier when combining graphics or dropping them into websites.
  4. The vector graphics would be suitable for web, print and games at any resolutions.
  5. Unit sizes would need to be normalized to a small set of scales.
  6. A wiki, style guide, tutorials and samples would be provided.
  7. SVG may also be used for basic animations.
  8. SVG inline in HTML5 may be scripted via the DOM.
  9. SVG should be inherently more accessible than bitmap images due to possibilities of description, zooming, applying high contrast styles and otherwise being more amenable to user customisation.

Note, however, that vector graphics have their limitations, and bitmap formats like JPEG/JFIF are better for photographic and similar images.


One of the best examples of such a library that I have found so far is the Integration and Application Network Symbol Libraries which contain over 2,700 symbols in six categories related to environmental science and ecology. These are in editable formats like SVG and Adobe Illustrator, and freely available under an attribution licence. They have a lot of documentation, videos, tutorials and a discussion forum for requests and submissions. They use a version of SVG Edit for their online conceptual diagram creator.

Summary and conclusion

I believe that open-licensed vector graphic component libraries could play an important role in supporting Open Educational Resources. The modern technological environment is more vector-friendly than ever, and there is now a very low entry threshold for educators who wish to add vector illustrations to their learning materials, with robust browser and mobile support; and free, online tools. Collections could be built up by communities of illustrators, editors and requestors, working to guidelines that can be developed as work progresses, informed by feedback from users and contributors.

To the extent possible under law, Sleeping Dog has waived all copyright and related or neighboring rights to the text of Proposal for an Open Educational Resource vector graphics library. This work is published from: United Kingdom.