Fractional points on <zone>?

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Fractional points on <zone>?

Martin Holmes
HI all,

There's an example in the Guidelines that has always bothered me, and
I'm wondering whether anyone can explain it or remember why it was
constructed this way. It's this one:

<http://www.tei-c.org/release/doc/tei-p5-doc/en/html/PH.html#index-egXML-d53e93796>

which shows a fairly straightforward use of <surface> and <zone> to
define an area on an image. What puzzles me is that the coordinate space
defined on the surface, which is 200 x 300, is then subdivided in the
zone/@points attribute, which uses floating-point numbers:

<facsimile>
  <surface ulx="0" uly="0" lrx="200" lry="300">
   <graphic url="Bovelles-49r.png"/>
   <zone points="4.8,31.0 5.4,30.7 5.5,32.2 5.8,32.8 6.1,33.4 5.5,33.7
5.1,33.3 4.6,32.2"/>
  </surface>
</facsimile>

My question is: why do this? Why define a coordinate space that you then
have to subdivide in this way? Since it's a user-defined coordinate
space, there's no need to do this at all. If the resolution of the image
is 200x300, then there's no real meaning in a value less than 1; if the
resolution of the image is higher, then why not use it for the
coordinate space?

Cheers,
Martin
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Re: Fractional points on <zone>?

Matthew Davis-2
I have no definitive answer for you, but my assumption has always been that those are x,y coordinates to use for an overlay.  So the surface is a 200x300 space, filled by the image file, and the zone indicates the boundaries of an initial or miniature within that space.


> On Dec 15, 2017, at 8:41 AM, Martin Holmes <[hidden email]> wrote:
>
> HI all,
>
> There's an example in the Guidelines that has always bothered me, and I'm wondering whether anyone can explain it or remember why it was constructed this way. It's this one:
>
> <http://www.tei-c.org/release/doc/tei-p5-doc/en/html/PH.html#index-egXML-d53e93796>
>
> which shows a fairly straightforward use of <surface> and <zone> to define an area on an image. What puzzles me is that the coordinate space defined on the surface, which is 200 x 300, is then subdivided in the zone/@points attribute, which uses floating-point numbers:
>
> <facsimile>
> <surface ulx="0" uly="0" lrx="200" lry="300">
>  <graphic url="Bovelles-49r.png"/>
>  <zone points="4.8,31.0 5.4,30.7 5.5,32.2 5.8,32.8 6.1,33.4 5.5,33.7 5.1,33.3 4.6,32.2"/>
> </surface>
> </facsimile>
>
> My question is: why do this? Why define a coordinate space that you then have to subdivide in this way? Since it's a user-defined coordinate space, there's no need to do this at all. If the resolution of the image is 200x300, then there's no real meaning in a value less than 1; if the resolution of the image is higher, then why not use it for the coordinate space?
>
> Cheers,
> Martin
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Re: Fractional points on <zone>?

Martin Holmes
HI Matthew,

Yes, I wasn't questioning the function of the zone; I was asking why
anyone would choose to define a coordinate space with a granularity
which was too coarse for the coordinates they need to express.

Cheers,
Martin

On 2017-12-15 08:51 AM, Matthew Davis wrote:

> I have no definitive answer for you, but my assumption has always been that those are x,y coordinates to use for an overlay.  So the surface is a 200x300 space, filled by the image file, and the zone indicates the boundaries of an initial or miniature within that space.
>
>
>> On Dec 15, 2017, at 8:41 AM, Martin Holmes <[hidden email]> wrote:
>>
>> HI all,
>>
>> There's an example in the Guidelines that has always bothered me, and I'm wondering whether anyone can explain it or remember why it was constructed this way. It's this one:
>>
>> <http://www.tei-c.org/release/doc/tei-p5-doc/en/html/PH.html#index-egXML-d53e93796>
>>
>> which shows a fairly straightforward use of <surface> and <zone> to define an area on an image. What puzzles me is that the coordinate space defined on the surface, which is 200 x 300, is then subdivided in the zone/@points attribute, which uses floating-point numbers:
>>
>> <facsimile>
>> <surface ulx="0" uly="0" lrx="200" lry="300">
>>   <graphic url="Bovelles-49r.png"/>
>>   <zone points="4.8,31.0 5.4,30.7 5.5,32.2 5.8,32.8 6.1,33.4 5.5,33.7 5.1,33.3 4.6,32.2"/>
>> </surface>
>> </facsimile>
>>
>> My question is: why do this? Why define a coordinate space that you then have to subdivide in this way? Since it's a user-defined coordinate space, there's no need to do this at all. If the resolution of the image is 200x300, then there's no real meaning in a value less than 1; if the resolution of the image is higher, then why not use it for the coordinate space?
>>
>> Cheers,
>> Martin
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Re: Fractional points on <zone>?

Conal Tuohy-3
In reply to this post by Martin Holmes
Hi Martin

NB the 200x300 coordinate space does not refer to the resolution of the image, though it may actually match (if the encoder has chosen to make their measurements in pixels, rather than physical units). The coordinates on the <surface> element should reflect the aspect ratio of the original page (which may vary from the page image, which often include margins), but its scale is entirely arbitrary. You could, for instance, multiply all numeric values in the example by 10, and the zone's points could then all be expressed as integers, while the semantics would remain exactly the same.

As to why someone would use a coordinate space in which their measurements are precise enough to have a fractional component, it might be that they have chosen to use millimeters or some other physical unit, for ease of measurement.

Conal

On 16 December 2017 at 02:41, Martin Holmes <[hidden email]> wrote:
HI all,

There's an example in the Guidelines that has always bothered me, and I'm wondering whether anyone can explain it or remember why it was constructed this way. It's this one:

<http://www.tei-c.org/release/doc/tei-p5-doc/en/html/PH.html#index-egXML-d53e93796>

which shows a fairly straightforward use of <surface> and <zone> to define an area on an image. What puzzles me is that the coordinate space defined on the surface, which is 200 x 300, is then subdivided in the zone/@points attribute, which uses floating-point numbers:

<facsimile>
 <surface ulx="0" uly="0" lrx="200" lry="300">
  <graphic url="Bovelles-49r.png"/>
  <zone points="4.8,31.0 5.4,30.7 5.5,32.2 5.8,32.8 6.1,33.4 5.5,33.7 5.1,33.3 4.6,32.2"/>
 </surface>
</facsimile>

My question is: why do this? Why define a coordinate space that you then have to subdivide in this way? Since it's a user-defined coordinate space, there's no need to do this at all. If the resolution of the image is 200x300, then there's no real meaning in a value less than 1; if the resolution of the image is higher, then why not use it for the coordinate space?

Cheers,
Martin



--
@conal_tuohy
+61-466-324297
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Re: Fractional points on <zone>?

Martin de la Iglesia-3
However, the coordinates in @points are still wrong in the context of this example: the prose text says the <zone> refers to a word in the bottom left corner of the page, but the coordinates suggest a position in the top left corner.

Martin

— 
Martin de la Iglesia
Kommentierte digitale Edition der Reise- und Sammlungsbeschreibungen Philipp Hainhofers (1578-1647)
Herzog August Bibliothek, Lessingplatz 1, 38304 Wolfenbüttel     Tel. +49 5331 808-125



Von: Conal Tuohy <[hidden email]>
An: <[hidden email]>
Gesendet: 16.12.2017 5:38
Betreff: Re: Fractional points on <zone>?

Hi Martin

NB the 200x300 coordinate space does not refer to the resolution of the image, though it may actually match (if the encoder has chosen to make their measurements in pixels, rather than physical units). The coordinates on the <surface> element should reflect the aspect ratio of the original page (which may vary from the page image, which often include margins), but its scale is entirely arbitrary. You could, for instance, multiply all numeric values in the example by 10, and the zone's points could then all be expressed as integers, while the semantics would remain exactly the same.

As to why someone would use a coordinate space in which their measurements are precise enough to have a fractional component, it might be that they have chosen to use millimeters or some other physical unit, for ease of measurement.

Conal

On 16 December 2017 at 02:41, Martin Holmes <[hidden email]> wrote:
HI all,

There's an example in the Guidelines that has always bothered me, and I'm wondering whether anyone can explain it or remember why it was constructed this way. It's this one:

<http://www.tei-c.org/release/doc/tei-p5-doc/en/html/PH.html#index-egXML-d53e93796>

which shows a fairly straightforward use of <surface> and <zone> to define an area on an image. What puzzles me is that the coordinate space defined on the surface, which is 200 x 300, is then subdivided in the zone/@points attribute, which uses floating-point numbers:

<facsimile>
 <surface ulx="0" uly="0" lrx="200" lry="300">
  <graphic url="Bovelles-49r.png"/>
  <zone points="4.8,31.0 5.4,30.7 5.5,32.2 5.8,32.8 6.1,33.4 5.5,33.7 5.1,33.3 4.6,32.2"/>
 </surface>
</facsimile>

My question is: why do this? Why define a coordinate space that you then have to subdivide in this way? Since it's a user-defined coordinate space, there's no need to do this at all. If the resolution of the image is 200x300, then there's no real meaning in a value less than 1; if the resolution of the image is higher, then why not use it for the coordinate space?

Cheers,
Martin



--
@conal_tuohy
+61-466-324297