# Alt text for equations

#### Do you have a question? Post it now! No Registration Necessary.  Now with pictures!

Threaded View
•  Subject
• Author
• Posted on

When equations involve fractions and radicals, I think it's just too
confusing to present them in line, so I use MS-Word Equation editor
to make a 2-D equation, then capture it as a GIF.

But then I have the problem of writing useful ALT text.  I'm not
happy with the job I'm doing there, and I wonder if, by way of an
example, someone can tell me how to improve on a particular one:

http://www.tc3.edu/instruct/sbrown/stat/pic/shape_g2.gif
alt="G sub 2 = fraction n minus 1, divided by n squared minus 5 n
plus 6, end fraction, times quantity n g sub 2 + g sub 2 + 6"

which occurs in this page:
http://www.tc3.edu/instruct/sbrown/stat/shape.htm

As you see, I've used commas (hoping for pauses in text-to-speech),
and avoided one level of parentheses by replacing (n-2)(n-3) with
n²-5n+6 and (n+1)g2 with ng2+g2. But still this strikes me as hard to
understand.  I wonder if there are some guidelines for folks who read
mathematics textbooks for the blind?

Thanks!

--
Stan Brown, Oak Road Systems, Tompkins County, New York, USA
http://OakRoadSystems.com /
HTML 4.01 spec: http://www.w3.org/TR/html401 /
validator:      http://validator.w3.org /
CSS 2.1 spec:   http://www.w3.org/TR/CSS21 /
validator:      http://jigsaw.w3.org/css-validator /
Why We Won't Help You:
http://diveintomark.org/archives/2003/05/05/why_we_wont_help_you

## Re: Alt text for equations

[...]

Would it make sense (for your audience) to present the alt text in
LaTex form?

Hmmm..., as usual I see Jukka has already made that suggestion:

<http://www.cs.tut.fi/~jkorpela/html/alt.html

Nick

--
Nick Theodorakis
nick_theodorakis@hotmail.com
contact form:
http://theodorakis.net/contact.html

Nick

## Re: Alt text for equations

Nick Theodorakis wrote:

The alternative text is supposed to be *readable*, so probably no.  (We've
been over this.  Try to view Wikipedia articles about a non-trivial
math/physics topic in lynx/links or let it be processed by a speech engine
to see what I mean.)

I can see no occurence of "(La)Tex" there.

PointedEars
--
Anyone who slaps a 'this page is best viewed with Browser X' label on
a Web page appears to be yearning for the bad old days, before the Web,
when you had very little chance of reading a document written on another
computer, another word processor, or another network. -- Tim Berners-Lee

## Re: Alt text for equations

Thomas 'PointedEars' Lahn wrote:

[...]

In the rules of thumb at the start, rule 9 contains:
"If the image has been generated using TeX or some of its derivatives, you
might consider using the TeX source code as alt text. TeX code might be
(perhaps via conversion to Braille) readable to some people who cannot see
the image, and it would thus be better than no useful alt text.)"

--
Yucca, http://www.cs.tut.fi/~jkorpela/

## Re: Alt text for equations

Jukka K. Korpela wrote:

Well then, you are wrong.

PointedEars
--
var bugRiddenCrashPronePieceOfJunk = (
navigator.userAgent.indexOf('MSIE 5') != -1
&& navigator.userAgent.indexOf('Mac') != -1
)  // Plone, register_function.js:16

## Re: Alt text for equations

Thomas 'PointedEars' Lahn wrote:

You were wrong at least in not finding the statement on my page. Now you are
saying I am wrong in some other thing, presumably in saying that code in TeX
or its derivative might be useful to some blind people. You did not make any
attempt at presenting an argument.

I have known a blind researcher who asked for LaTeX source code for some
equations, saying he was accustomed to reading LaTeX source. This is
sufficient evidence for me. I won't bother asking what evidence you have for
your point that appears to be that _nobody_ can ever benefit from having
(La)TeX source available as alternative for an image, since that point is
obviously absurd.

--
Yucca, http://www.cs.tut.fi/~jkorpela/

## Re: Alt text for equations

Jukka K. Korpela wrote:

One cannot be wrong in not finding something.

I was and I am saying that you are wrong assuming that

| TeX code might be (perhaps via conversion to Braille) readable to some
| people who cannot see the image, and it would thus be better than no
| useful alt text.

The argument was and is that the usual speech engines cannot process it so
that it is easily understood.  For example, espeak using English reads

"AM=\frac\sum_^na_i. "

from <http://en.wikipedia.org/wiki/Average#Arithmetic_mean as

"AM equals backstroke frac one n backstroke sum i equals one n'ai"

when it should have read (CMIIW, English is not my native language)

"AM equals 1 divided by n, multiplied by the sum of a' subscript i'
where i' ranges from one to n."

PointedEars
--
var bugRiddenCrashPronePieceOfJunk = (
navigator.userAgent.indexOf('MSIE 5') != -1
&& navigator.userAgent.indexOf('Mac') != -1
)  // Plone, register_function.js:16

## Re: Alt text for equations

You can be wrong in the implication that it is not there. Do you
really or do you just pretend to run on literal rails. Please
send me a scoop of your brain for analysis in my lab - use a
clean teaspoon inserted into the ear.

--
dorayme

## Re: Alt text for equations

Thomas 'PointedEars' Lahn wrote:

This is the first time in this discussion you present anything resembling an
argument.

You claimed that it was wrong to say that some people might benefit from
(La)TeX notations. Do you really think that your opinions about "the usual
speech engines" (of which you only mention espeak as an example!) prove
that?

Do you think that a mathematically educated person (and this is really about
content written for more or less mathematically educated people) could not
possibly understand (La)TeX code as such, when hearing the characters as
written or reading them with fingertips? I don't actually care what you
think, since such people have told me otherwise.

--
Yucca, http://www.cs.tut.fi/~jkorpela/

## Re: Alt text for equations

Jukka K. Korpela wrote:

Your inability to recognize an argument for what it is does not make it
suddenly disappear.

Yes, I do.

*If* they hear them.  You have not even tried the example, have you?

Great, I don't care about your unfounded opinion in this either.

You miss the point.  Visitors of a site containing equations are not
necessarily well-versed in LaTeX, nor do they need to have a speech engine
that can read it properly, or would they want to have LaTeX syntax read to
them.  I have proven your all-quantified statement wrong by providing one
counter-example of a widely used Open-Source speech engine that, despite
being fed with the list of delimiters, cannot read that equation so that it
is easily understood.  I am sure you can find other examples on your own,
not that they would be necessary.

PointedEars
--
Prototype.js was written by people who don't know javascript for people
who don't know javascript. People who don't know javascript are not
the best source of advice on designing systems that use javascript. --

## Re: Alt text for equations

Thomas 'PointedEars' Lahn wrote:

You made a general statement, which refuted my statement about some people
possibly benefiting from (La)TeX source in alt attributes. Thereby you made
the claim that nobody can possibly benefit from (La)TeX source in alt
attributes. You then said that you regard your own opinion about "the usual
speech engines" as an argument.

Are you totally challenged in elementary logic (reasoning), or just
pretending to be?  That was a rhetorical question of course. Your relatively
short visit to c.i.w.a.h. has been sufficiently long to indicate that you
are either a troll or some other kind of nuisance. We will probably see you
disappearing soon, as people will ignore you.

--
Yucca, http://www.cs.tut.fi/~jkorpela/

## Re: Alt text for equations

In comp.infosystems.www.authoring.html message <KXOLn.13624\$if1.62@uutis
et.elisa.fi>, Fri, 28 May 2010 15:37:39, Jukka K. Korpela

Look up his posting history elsewhere, and you will not need to ask.

You exhibit a degree of optimism which is quite unjustified by what the
aforementioned lookup would indicate.

--
(c) John Stockton, nr London UK. ?@merlyn.demon.co.uk  Turnpike v6.05   MIME.
Web  <URL:http://www.merlyn.demon.co.uk/ - FAQish topics, acronyms, & links.
Proper <= 4-line sig. separator as above, a line exactly "-- " (RFCs 5536/7)
Do not Mail News to me. Before a reply, quote with ">" or "> " (RFCs 5536/7)

## Re: Alt text for equations

On Thu, 27 May 2010 23:13:47 +0300, Jukka K. Korpela wrote:

Reminder: Don't feed the trolls. :-)

--
Stan Brown, Oak Road Systems, Tompkins County, New York, USA
http://OakRoadSystems.com /
HTML 4.01 spec: http://www.w3.org/TR/html401 /
validator:      http://validator.w3.org /
CSS 2.1 spec:   http://www.w3.org/TR/CSS21 /
validator:      http://jigsaw.w3.org/css-validator /
Why We Won't Help You:
http://diveintomark.org/archives/2003/05/05/why_we_wont_help_you

## Re: Alt text for equations

Don't you ever go fishing Stan? If there was a way to only bait
for the fish you wanted, would that not take something away from
the fun? It is quite surprising how tasty the generally unwanted
cat fish can be served, I personally experienced it at a BBQ at
St Albans in NSW. I reckon the cook there would have made a nice
dish of even some pointed ears.

--
dorayme

## Re: Alt text for equations

On Thu, 27 May 2010 05:30:17 -0700 (PDT), Nick Theodorakis wrote:

thanks for responding.

Yes, I saw that.  But I don't know TeX, and I am pretty sure the
majority of my audience wouldn't.

I do try to present formulas in line where practical.  But over the
years I've come to draw the line more and more.  Something like
[ ( x + y ) ^ (1/3) ]
is okay, but showing it with a radical sign and index is a lot
clearer.  And when fractions and radicals are mixed, I really think
it's asking too much of the reader to decode inline notation on the
Web.

--
Stan Brown, Oak Road Systems, Tompkins County, New York, USA
http://OakRoadSystems.com /
HTML 4.01 spec: http://www.w3.org/TR/html401 /
validator:      http://validator.w3.org /
CSS 2.1 spec:   http://www.w3.org/TR/CSS21 /
validator:      http://jigsaw.w3.org/css-validator /
Why We Won't Help You:
http://diveintomark.org/archives/2003/05/05/why_we_wont_help_you

## Re: Alt text for equations

In comp.infosystems.www.authoring.html message <MPG.2668e81ff187499e98c2
ac@news.individual.net>, Thu, 27 May 2010 21:36:19, Stan Brown

With JavaScript, you can compose anything you want, including formulae,
in a <canvas> element - all current browsers except for IE8 & clones.  I
presume, not having tried it, that a <canvas> can be displayed inline
(but its contents are easily transferred to a PNG, which surely can).

<URL:http://www.merlyn.demon.co.uk/js-grphx.htm , while not quite a demo
of that, should indicate the possibility.

--
(c) John Stockton, nr London UK.  ?@merlyn.demon.co.uk  IE8 FF3 Op10 Sf4 Cr4
news:comp.lang.javascript FAQ <URL:http://www.jibbering.com/faq/index.html .
<URL:http://www.merlyn.demon.co.uk/js-index.htm jscr maths, dates, sources.
<URL:http://www.merlyn.demon.co.uk/ TP/BP/Delphi/jscr/&c, FAQ items, links.

## Re: Alt text for equations

Stan Brown writes:

See also the second part ("Interestingly, it turns out ...") of

http://scienceblogs.com/cortex/2010/04/dont_choke.php

. (When reminded of a stereotype that women perform worse
in mathematics, they indeed perform worse, /but only when
the term is written in line/.)

## Re: Alt text for equations

On 27 May 2010 12:40:49 GMT, Stefan Ram wrote:

Interesting stuff.  Did you read down to the comments?  Several
possible explanations were given why the arrangement of the problem
might make a difference. For instance, totting up a column of figures
is easier that totting up a row because of "carry the one".

--
Stan Brown, Oak Road Systems, Tompkins County, New York, USA
http://OakRoadSystems.com /
HTML 4.01 spec: http://www.w3.org/TR/html401 /
validator:      http://validator.w3.org /
CSS 2.1 spec:   http://www.w3.org/TR/CSS21 /
validator:      http://jigsaw.w3.org/css-validator /
Why We Won't Help You:
http://diveintomark.org/archives/2003/05/05/why_we_wont_help_you

## Re: Alt text for equations

I'd spell it out, although this would, of course, be ponderous with
large equations.  Nevertheless:

(n-2)(n-3) =
n minus 2 sum times n minus 3 sum

(n-2)n-3
n minus 2 sum times n minus 3

(n+1)g2
n plus 1 sum times g times 2 (-if by "g2" you correctly indicate g
times 2. If "g2" is a single quantity name, it should be so-indicated.)

--
Neredbojias

http://www.neredbojias.org /
http://www.neredbojias.net /

## Re: Alt text for equations

Neredbojias wrote:

I am not well-versed in mathematical English, but this does not sound
remotely correct.  There is is no "sum" whatsoever in between.  And "sum
times"?

So if anything, the parentheses should be read/written like "opening
parenthesis n minus two closing parenthesis multiplied by opening
parenthesis n minus 3 closing parenthesis" (left-to-right, this is probably
easier to implement) or "n minus 2 in parentheses multiplied by n minus 3 in
parentheses" (grouped) for (n - 2)(n - 3)'.

PointedEars
--
var bugRiddenCrashPronePieceOfJunk = (
navigator.userAgent.indexOf('MSIE 5') != -1
&& navigator.userAgent.indexOf('Mac') != -1
)  // Plone, register_function.js:16