Saturday 18 April 2015

Gestalt - An Overview

By now this blog has finally started to take some proper shape.  Organically, the search for answers has opened up a number of fronts, with spotlights variously on birds and light, colour, field marks, forensics, human bias and the image quality tool that started it all off.  This has all arisen from a simple germ of an idea - that it might be possible to create a digital guide to identification from photos, specifically for birders.  These broad areas of research can all be explored as individual pages from the top right-hand corner of the blog.  To these topics I have now added Gestalt.  

'Gestalt' (or 'G.I.S.S.' - 'general impressions of size and shape' - also spelt 'JIZZ') is the name we give to the recognisable 'feel' of an individual species in the wild.  It is a combination of it's structure, how it moves and it's behaviour.  As birders gain experience in the field we quickly become aware of the gestalt of common species we encounter regularly.  When a new species appears in a familiar setting, very often it's presence is first signalled by it's gestalt - something unusual about it's size and shape, or the way it feeds or moves about.  Of course a common species with an uncharacteristic behaviour or shape can fool an observer into believing they are watching a different species.  It is also very difficult to describe a bird's gestalt in any objective or measurable way.  Thus this subtle field craft has it's pros and cons, it's strong advocates and those who are more into field marks.  Most experienced birders would tend to use gestalt a lot in forming an initial impression but combine that with topographic field marks to form a solid identification.

It would be wrong to say that gestalt can be properly captured in an individual photograph but video can go a long way to capturing it.  Then again, if a video is merely a collection of photos, surely a flavor of a bird's gestalt is captured in every single photograph or frame of video.  The question is, how do we reliably and consistently draw out from our photographs this 'essence', for want of a better description.

General Impressions of Size and Shape
Sometimes size and structure are wrapped up together in the definition of field marks and I don't think this is helpful, so I am intentionally splitting out structure (or morphology) and size (or biometrics) from the field marks question and tackling them separately here under gestalt.  In a Spotlight On Field Marks you will note I have deliberately separated structure and size from the patterns, colours and markings which I think forms a clearer, more concise definition of field marks.  
It might be tempting to think of a photograph as a good representation of size and proportion but this can be a very unwise assumption.  I have looked at this in some detail already HERE and I will be building on this analysis in future posts.

Tools and Guides
In a Gestalt Field Guide I looked at how the subtle question of gestalt has been handled in standard field guides.  Possibly the first overt attempt to deal with this came with the publication of Birds by Character by Rob Hume and illustrated by Ian Wallace, Darren Rees, John Busby and Peter Partington in 1990. 

Though the book is clearly a concise field guide, the sketchbook styled plates mark it's utter uniqueness among field guides.  Experienced birders will certainly appreciate how well gestalt has been captured in this book.  But this type of guide doesn't necessarily lend itself to an analysis of birds or gestalt from digital images.  The key issue here I think is that field guides, by their nature cannot capture enough of the essence of a species to allow them to be used for direct comparison with photos.  One book has gone much further than any other I have seen, and that is Hawks at a Distance by Jerry Liguori.  But it is interesting to note for instance that, despite showing fewer stills of Northern Goshawk, there was more of the behaviour of that species captured in Birds by Character than in Hawks at a Distance.  So there is clearly a lot to consider here and no easy approach to tackling and illustrating gestalt in a field guide. 

I actually gave a bit of thought to the subject of how best to characterise gestalt from images very early on in the development of this blog and I came up with a simple matrix to help describe the overall quality of an observation based on a single image.  Perhaps this is a better starting point.  So far I have concluded that most bird images fit into one of nine categories, where a bird can be described as either in near side profile (generally the best viewing angle), near front/back profile, or clearly offset from one of these.  I then categorised birds in images as either being at rest, though perhaps "on the deck" is a better way of putting it as it doesnt preclude birds from actively feeding, preening or whatever.  Alternatively birds may be in flight.  Or, lastly birds may be captured about to take flight or land - I referred to this as "open wing" in the matrix (below).  While I may find this to be an oversimplification in time, I am going to use it as a starting point for further analysis around this whole question.

I am in little doubt that the best tool for studying gestalt is a moving image.  Video offers it all - size, shape, behaviour and, when put together, that essence that defines a living species which we call gestalt.  I have only just touched on this so far but I have a good collection of video gathered over the years in various formats and in various countries and environments.  I look forward to starting to train the blog in the direction of that stash of material.  Not only is there plenty of room to look at ways to extract and study gestalt, such as the useful animated gif technique which I showcased a while back on the blog.  There is also plenty of scope to look at image analysis techniques in the video sphere.

So, in summary, this is a very big field in itself with plenty of room for exploration and further twists and turns.  I will be digging into various areas and looking forward to seeing how the blog develops and where the research takes us.

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