Sunday, July 14, 2013

A word on visuals: Redrawing a diagram

Scientist and engineers need diagrams to express ideas, and so they make it into a presentation's visual stack. Some caution is necessary when inserting diagrams into a presentation's visual stack.  Some could come in the form of a scanned document, some could come from a cropped pdf, or a image file. Biology Professor Zen Faulkes  has also written about the topic of redrawing here.

Here is an example of a diagram that needs to be redrawn:
If I would have inserted this diagram as it is there would  have been several problems, including
  • Not all text would have been legible. 
  • The diagram would have included information the audience doesn't need.
  • The diagram might have looked pixelated.
In other words, I would have lost control over it. I can recover the control by redrawing the diagram. Nowadays it is fairly easy to do this. High quality SVG maps are released under public domain or Commons Creative licenses. Plus, open source for manipulating vector graphics are not only free-of-charge, but also multiplatform.  Here is end result of my remake.
Finished slide

The actual colors (see below) are the result of the different transparency value assigned to each country and the slide background. I added  the color legend and the result of the text on Keynote. In fact I animated the color legend to layer the information presented on the slide.
video

As I mentioned the finished map does not come directly from the vector graphics program. Here is the raw version. Note how the light green turns dark and viceversa in the finished result. This is a result of the dark blue background. That color is also playing the role of the ocean. The new diagram is not 100% the same as the original one. It zooms-in more than the original. In the latter the whole  black sea and the southern part of Italy are shown, but do I needed them? No. 
Slide's raw version right out of Inkscape
Are there other benefits in remaking a diagram? The new diagram is now consistent with the style of my overall visual stack. I could also reuse the diagram in a written document.

Should all diagrams be redrawn? No. Some diagrams might be just fine as they are. Also there is the practical issue of time. This takes time on preparing a talk. In case of doubt, use the time to rehearse, not to redraw. And if you think you might need the diagram as a building block of for research presentation, redraw it after the talk and use it on the next one. Remember that a raw version could be reuse in a written document.  

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