[accessibleimage] Re: Tactile arrows

Don
The symbol you are talking about is obviously similar to the one way 
arrow which was produced by using a specially designed embossing wheel.

See Schiff, W., Kaufer, L. and Mosak, S. 1966.  Informative tactile 
stimuli in the perception of direction.  Perceptual and Motor Skills 23, 
1315-1335.

Ron Hinton had some plastic strips made to replicate this symbol and I 
was given a slack handful by NCTD to use.  I found that they were good 
when placed side by side to represent stairs if the scale of the map 
allowed such a large symbol.  The meaning was deduced by totally blind 
testers but the problem was does one have the smooth run travelling up 
or down the slope.  I have not found any recorded thoughts on this 
aspect and consultation with visually impaired users didn't help my 
dilemma.
My thoughts were to have the smooth run down the slope and the stepped 
run up the slope to replicate the action of walking up a flight of 
steps.

The arrow head shape for stairs comprising a series of parallel lines 
decreasing in length (Wiedel) poses the same problem - is the point at 
the top of the slope or the bottom?  Any arrow would have the same 
ambiguity in the absence of any recognised standardisation of design.

When using vacuum forming techniques it is sometimes possible to put in 
stairs between different levels in which case the little preformed 
stairs symbols sold by RNIB work very well as they replicate to a 
certain extent the real life form.  As these symbols come in a pack with 
a load of other symbols it is not particularly easy to have a large 
number without buying a surfeit of unwanted stuff.  I have used styrene 
strips which I stuck together to form a stepped strip and then cut it 
into the required widths.  This method means that you can change the 
dimensions according to the scale of the map also the edges of the 
styrene are sharper than the injection moulded symbols which helps the 
feel when a small scale is used.

The Tiger pattern of using grey scale blocks to emboss bands of dots 
with incremental heights works well and it is obvious to the touch that 
the symbol means stairs or steps.

Of course it is not possible to define the correct number of steps in 
most cases and the symbol should be described in the 'how to read' 
information and the detail of the real life feature associated with it.

The symbolisation of stairs is one that constantly poses problems and 
any one solution is unlikely to satisfy every case - the biggest hurdle 
is the scale.  If a symbol could be designed that works at every scale - 
suitably enlarged or diminished - and for every technique - swell paper, 
braille embosser, vacuum forming or plastic printing it should be set up 
as a standard and we should all try hard to use it.

If you are talking about arrows rather than stairs I have found that a 
head comprising 2 lines at right angles bisected by a stem works well in 
a range of sizes.  The sharper the line the better so that the point is 
really pointed. Easier with V/F than swell paper.

Apart from the shape has anyone done anything about the readability of 
dotted lines versus smooth lines for arrows?  I feel that using a dotted 
line - braille size dots - would enhance the sharpness in some cases but 
if space is limited it might just be very confusing - there is probably 
a minimum size for a dotted arrow - just a thought to start you 
thinking!

Ann





In message <LEEEIPIGGNOEGPKDKCKJGEGJCDAA.d.j.mccallum@xxxxxxxxx>, Don 
Mccallum <d.j.mccallum@xxxxxxxxx> writes
>Hi all,
>
>I was wondering what experience people had with arrows (or stair symbols) on
>tactile diagrams?
>For example, as anyone found any shape, design or size of arrow to be
>superior to others?
>We are trying a 'saw-tooth' arrow.  Put simply, this a line that feels rough
>in one direction and smooth in the other, hopefully indicating direction.
>Has anyone had experience with this?
>
>Regards
>
>Don
>
>Don McCallum
>Anglia Polytechnic University
>d.j.mccallum@xxxxxxxxx
>www.timp.org.uk
>
>
>-----Original Message-----
>From: accessibleimage-bounce@xxxxxxxxxxxxx
>[mailto:accessibleimage-bounce@xxxxxxxxxxxxx]On Behalf Of Lisa Yayla
>Sent: 01 March 2005 13:34
>To: accessibleimage@xxxxxxxxxxxxx
>Subject: [accessibleimage] Article Journal of Visual Impairments and
>Blindness
>
>
>Hi,
>Sending a notice about an article in the Feb 2005 issue of JVIB vol. 99
>number 2
>Tactile Graphics: An Evaluation of Substrates for Tactile Maps and
>Diagrams by
>Sarah Jehoe, Simon Ungar, Don McCallum and Jonathan Rowell.
>Haven't read it yet, but surely a good read.
>Regards,
>Lisa
>
>Lisa Yayla
>Huseby Kompetansesenter
>Oslo Norway
>lisa.yayla@xxxxxxxxxx
>
>
>
>

-- 
Ann Gardiner
tel:01928 733040

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