user10100: I can't use the Path of Purification PDF version of AccessToInsight.org because ...

I want to restructure/retranslate Visuddhimagga into english.
I want to add the reference link in each word of Visuddhimagga to the source in tipitaka.
I want to make the link directly to the expected page of Visuddhimagga and make the highlight to the expected text when I answer or make an article.

... so I want the computerised text version, to publish in HTML format on the internet.
It requires a very long time to do a new translation of it all, because English is not my native language -- and I require a very long time as well to translate pāli even in my native language -- and so I think it would be faster and more effective to restructure from another's version/translation.
Therefore: 

Is there a free (i.e. libre or open) version of Visuddhimagga in a computerized text format?
Is there a computerised text version of the Budaedu's Visuddhimagga version?

Or can you tell me about obtaining permission (and the data) from a copyright holder?

I'm principally looking for something like a license which allows:

Distribution and
Creating a derivative work

... and a corresponding text format which can be converted to e.g. HTML.

user14468: I suppose the "Path of Purification" available at AccessToInsight.org is the third online edition of the Visuddhimagga which you've mentioned as "Budaedu's Visuddhimagga version". So, it's better if you use the most recent edition.
Under the terms of use in the PDF book, "Path of Purification" it has mentioned:

Copyright revised, third, online edition. Copyright © 2011 Buddhist Publication Society.
You may redistribute this PDF file in an unaltered form provided that:
  (1) you must only make such unaltered PDF copies available free of charge;
  (2) you clearly indicate that any passages of this work reproduced into other publications (printed as well as digital) are derived from this source document. Otherwise, all rights reserved.

So, whenever you use any passages from this book always keep in mind to give references to the source document. It's much better to contact Buddhist Publication Society before you start the work and get a written approval as such copyright notices can be interpreted differently.
Address:
Buddhist Publication Society,
P.O. Box 61, 54,
Sangharaja Mawatha,
Kandy,
Sri Lanka.
Email: bps@bps.lk
Tel: +94 81 2237283
Fax: +94 81 2223679

user254: The two versions of the PDF (i.e. Budaedu and Access to Insight -- and actually the copy on Access to Insight's was published by the Buddhist Publication Society) are both based on similar text (i.e. translated from the Pali by Bikkhu Nanamoli).
I know approximately what PDF format is (i.e. it's a container for data) but don't know it well (e.g. I don't know the many software tools available to work with it) -- based on that, I think that:

Budaedu's PDF appears to contain images (photographs of the pages, not text)
The A2I/BPS PDF seems to contain text (you can select words), but you can't copy words -- I don't know why, e.g. if that's because it's copy-protected or some other reason. I'm sure it is text, though, e.g. because I can search for (and find) words in it like "edition" -- and because there's a "Publisher's note" which thanks volunteers who converted a "previous edition to digital text".

If you only have images of pages, one possibility might be to use any OCR software to convert it to text. That (the "recognition" process) isn't error-free but may be good, i.e. if you can read the image easily then so can a computer. Apparently the BPS already did that in their edition.
It was translated in 1956 -- I don't know who has the copyright or whether it was e.g. copyleft somehow by the author. Normally (i.e. in law) the author would automatically have the copyright -- unless they assign it to someone else, e.g. to a publisher, or to the public domain.
So I think you have two problems:

Discover the copyright status. You cannot ask the author (i.e. the translator), perhaps you can ask one of publishers e.g. http://www.bps.lk
Get a file with suitable format -- in that file doesn't already exist someone might create one, whether using OCR or a PDF conversion library or something I don't know -- a solvable problem, a non-trivial problem however, but maybe a software problem, one that might require volunteers.

I guess that any publisher might have copyright of their own version -- e.g. even if the underlying text is public domain, possibly the BPS have copyright of their version because they went to the effort of converting it to a more usable format, or something like that.
So, theoretically, unless you find data which says "free to redistribute and modify" or "public domain", it may be best to get permission from whichever publisher it is before you base your further work on their publication.
I'm not certain that your use-case is covered by the permissions granted which are quoted in Damith's answer (which allow you to copy the whole PDF unaltered -- or, to reproduce parts of it in other publications).
Some people disagree with the whole concept of copyright, but if you're not one of them you might want to ask the publisher -- explain what you want and try to get their permission.

user18: I converted the pdf to html some years ago using pdf2html but due to copyright issues it can't be shared publicly. When I posted it on our website, the publisher (a Buddhist monk) promptly threatened to sue. I doubt getting permission from the publisher would be easy, unless leadership has changed in the meantime.
Nyanamoli's original translation should enter the public domain soon, I think... Since it was published in Sri Lanka, you'd have to figure out what that means for using it in your country. I think the current pdf would be considered a derivative work of the original.
If you just want an html version without actual legal permission, I still have the html version I made.

user14609: on archive.org you usually get several file types, for the text alone
https://archive.org/download/Visuddhimagga-ThePathOfPurification

10100: <p>I can't use the <em>Path of Purification</em> <a href="https://www.accesstoinsight.org/lib/authors/nanamoli/PathofPurification2011.pdf" rel="nofollow noreferrer">PDF version</a> of AccessToInsight.org because ...</p>

<ol>
<li>I want to restructure/retranslate Visuddhimagga into english.</li>
<li>I want to add the reference link in each word of Visuddhimagga to the source in tipitaka.</li>
<li>I want to make the link <strong>directly</strong> to the expected page of Visuddhimagga and make the highlight to the <a href="http://www.84000.org/tipitaka/read/roman_read.php?B=14&amp;A=4036&amp;h=an%C4%81thapi%E1%B9%87%E1%B8%8Dikassa,mah%C4%81nisa%E1%B9%83s%C4%81ti#hl" rel="nofollow noreferrer">expected text</a> when I answer or make an article.</li>
</ol>

<p>... so I want the computerised text version, to publish in HTML format on the internet.</p>

<p>It requires a very long time to do a new translation of it all, because English is not my native language -- and I require a very long time as well to translate pāli even in my native language -- and so I think it would be faster and more effective to restructure from another's version/translation.</p>

<p>Therefore: </p>

<ol>
<li>Is there a free (i.e. <a href="https://en.wikipedia.org/wiki/Gratis_versus_libre" rel="nofollow noreferrer">libre</a> or <a href="https://en.wikipedia.org/wiki/Open_source" rel="nofollow noreferrer">open</a>) version of Visuddhimagga in a computerized text format?</li>
<li>Is there a computerised text version of the <a href="http://ftp.budaedu.org/ebooks/pdf/EN081.pdf" rel="nofollow noreferrer">Budaedu's Visuddhimagga version</a>?</li>
</ol>

<p>Or can you tell me about obtaining permission (and the data) from a copyright holder?</p>

<hr>

<p>I'm principally looking for something like <a href="https://creativecommons.org/licenses/" rel="nofollow noreferrer">a license</a> which allows:</p>

<ul>
<li>Distribution and</li>
<li>Creating a derivative work</li>
</ul>

<p>... and a corresponding text format which can be converted to e.g. HTML.</p>
 14468: <p>I suppose the "Path of Purification" available at AccessToInsight.org is the third online edition of the Visuddhimagga which you've mentioned as "Budaedu's Visuddhimagga version". So, it's better if you use the most recent edition.</p>

<p>Under the terms of use in the PDF book, "Path of Purification" it has mentioned:</p>

<blockquote>
  <p>Copyright revised, third, online edition. Copyright © 2011 Buddhist Publication Society.</p>
  
  <p>You may redistribute this PDF file in an unaltered form provided that:<br>
  (1) you must only make such unaltered PDF copies available free of charge;<br>
  (2) you clearly indicate that any passages of this work reproduced into other publications (printed as well as digital) are derived from this source document. Otherwise, all rights reserved.</p>
</blockquote>

<p>So, whenever you use any passages from this book always keep in mind to give references to the source document. It's much better to contact Buddhist Publication Society before you start the work and get a written approval as such copyright notices can be interpreted differently.</p>

<p>Address:<br>
Buddhist Publication Society,<br>
P.O. Box 61, 54,<br>
Sangharaja Mawatha,<br>
Kandy,<br>
Sri Lanka.</p>

<p>Email: bps@bps.lk</p>

<p>Tel: +94 81 2237283<br>
Fax: +94 81 2223679</p>
 254: <p>The two versions of the PDF (i.e. Budaedu and Access to Insight -- and actually the copy on Access to Insight's was published by the Buddhist Publication Society) are both based on similar text (i.e. translated from the Pali by Bikkhu Nanamoli).</p>

<p>I know approximately what PDF format is (i.e. it's a container for data) but don't know it well (e.g. I don't know the many software tools available to work with it) -- based on that, I think that:</p>

<ul>
<li>Budaedu's PDF appears to contain images (photographs of the pages, not text)</li>
<li>The A2I/BPS PDF seems to contain text (you can select words), but you can't copy words -- I don't know why, e.g. if that's because it's copy-protected or some other reason. I'm sure it is text, though, e.g. because I can search for (and find) words in it like "edition" -- and because there's a "Publisher's note" which thanks volunteers who converted a "previous edition to digital text".</li>
</ul>

<p>If you only have images of pages, one possibility might be to use any <a href="https://en.wikipedia.org/wiki/Optical_character_recognition" rel="nofollow noreferrer">OCR software</a> to convert it to text. That (the "recognition" process) isn't error-free but may be good, i.e. if you can read the image easily then so can a computer. Apparently the BPS already did that in their edition.</p>

<p>It was translated in 1956 -- I don't know who has the copyright or whether it was e.g. <a href="https://en.wikipedia.org/wiki/Copyleft" rel="nofollow noreferrer">copyleft</a> somehow by the author. Normally (i.e. in law) the author would automatically have the copyright -- unless they assign it to someone else, e.g. to a publisher, or to the <a href="https://en.wikipedia.org/wiki/Public_domain" rel="nofollow noreferrer">public domain</a>.</p>

<p>So I think you have two problems:</p>

<ul>
<li>Discover the copyright status. You cannot ask the author (i.e. the translator), perhaps you can ask one of publishers e.g. <a href="http://www.bps.lk" rel="nofollow noreferrer">http://www.bps.lk</a></li>
<li>Get a file with suitable format -- in that file doesn't already exist someone might create one, whether using OCR or a PDF conversion library or something I don't know -- a solvable problem, a non-trivial problem however, but maybe a software problem, one that might require volunteers.</li>
</ul>

<p>I guess that any publisher might have copyright of their own version -- e.g. even if the underlying text is public domain, possibly the BPS have copyright of their version because they went to the effort of converting it to a more usable format, or something like that.</p>

<p>So, theoretically, unless you find data which says "free to redistribute and modify" or "public domain", it may be best to get permission from whichever publisher it is before you base your further work on their publication.</p>

<p>I'm not certain that your use-case is covered by the permissions granted which are quoted in <a href="https://buddhism.stackexchange.com/a/30619/254">Damith's answer</a> (which allow you to copy the <strong>whole</strong> PDF <strong>unaltered</strong> -- or, to reproduce <strong>parts</strong> of it in other publications).</p>

<p>Some people disagree with the whole concept of copyright, but if you're not one of them you might want to ask the publisher -- explain what you want and try to get their permission.</p>
 18: <p>I converted the pdf to html some years ago using pdf2html but due to copyright issues it can't be shared publicly. When I posted it on our website, the publisher (a Buddhist monk) promptly threatened to sue. I doubt getting permission from the publisher would be easy, unless leadership has changed in the meantime.</p>

<p>Nyanamoli's original translation should enter the public domain soon, I think... Since it was published in Sri Lanka, you'd have to figure out what that means for using it in your country. I think the current pdf would be considered a derivative work of the original.</p>

<p>If you just want an html version without actual legal permission, I still have the html version I made.</p>
 14609: <p>on archive.org you usually get several file types, for the text alone
<a href="https://archive.org/download/Visuddhimagga-ThePathOfPurification" rel="nofollow noreferrer">https://archive.org/download/Visuddhimagga-ThePathOfPurification</a></p>
