precision of Draw dimensions - 3 place

users
#21

hello
for now i-m understand, then my experience graphics, publisher, greeting card, with LOD is good but not TOP because LOD is not professional for VECTOR GRAPHIC, to be software high flexibilit and high professional is INKSCAPE, (there are many functional like as CAD, Rhino 3d for SNAP for node and path, shapes, page.  i say : it's besf for you is INKSCAPE, but LOD is good for base, LOD vs INKSCAPE: WINNER is INKSCAPE. LOD cant not compare to inkscape..becausa inkscape compare vs to illustrator (adobe) ok?scribus is for page magazine, book, high professional, LOD or LOW is good, but libreoffice will be enhancement ok?
but i like libreoffice againt to microsoft office (dollars) ok?

#22

For discussion's sake only, not to start an argument, if you are going to measure in inches as your selection, then to expand on that, would you want your font to be measured in inches instead of points?

<snip>

#23

Mike,

Well done! I fully agree with you-

I opened a new calc document, changed the measurement unit from cm to inches. That marked my document as being changed!
As far as I see there's nothing changed in the document....

Then I changed a column width to 1 (inch) and saved
I took another document to change back from inches to cm.

Then I opened the first document to find that the column width is set to 2.54 cm

So, it seems that the measurement unit is not saved in the document.
However, when I change the default measurement unit the file is marked as changed! Why? Rounding???

What should happen is that the measurement unit is saved in the document, not the rounded internal value.

#24

See bottom for continuation of discussion.

A bit of a rant. My apologies and respect to all who have made Draw
possible in advance.

Hi Dave,

dave boland schrieb:

Thanks all. If I make a suggestion to LO - add some more CAD abilities
to Draw such as higher precision.

The current internal precision is 1/100 mm. Armin Le Grand had started
to change Draw to number format double to allow higher precision, see
https://wiki.openoffice.org/wiki/Aw080_documentation. Unfortunately
there is currently no Company which will pay for finishing that work.

Thank you for pointing this out.

You can get a very high precision in the UI, if you view the drawing
with 3000% zoom and move/scale the objects using the array keys
together with the Alt-key.

If you insist on the inch system, and need fractions of inches, you
should change the unit from inch to point. It is 72 point = 1 inch, so
0.125 inch can be entered as 9 point, and with such number there is no
problem in the UI. But you should notice that 1 inch = 2.54 cm and
therefore 0.125 inch = 0.3175 cm = 317.5 * 1/100mm. It cannot be
represented exactly with the internal 1/100mm unit.

If I insist on the inch system, I should use inches. Not meant to be
harsh, but really?
Can't debate your math, but shouldn't data be entered as it is measured?

For discussion's sake only, not to start an argument, if you are going to measure in inches as your selection, then to expand on that, would you want your font to be measured in inches instead of points?

<snip>

All measurement is application specific, using the speed of light as an interpretation of inches or fonts, although accurate, is not reasonable for CPU cycles.
It is very much like the 'epoch' date problem. The underlying math is singular, but results are interpreted as seconds, days, months that we use are not.
The "Today" function is derived from the 'Epoch' calculations so it is understood by anyone using it. It is not loose, but reasonable within expectation.

To think in other manner may not be folly, but it will still result in inconsistency.

Today, we still have the mathematical 'rounding' problem that results in different accounting results.
(Hmmm, where did the thousand dollars go in that billion dollar transaction)

Compare Calcs' underlying method for time and date and Draws' underlying method for measurements.

As an example of one method, when a page is created, the first point is created which becomes a reference for any other position using A2 + B2 = C2 within X Y Z co-ordinates and it's "measurement" is mathematically derived into inches, pica's, millimeters, etc.. While Draw must use basic math correctly underneath, the interpreted results in measurement do not follow functionally.

This issue recognized, I still love using it and LibreOffice.

Ref: Calc for Date & Time Functions for Calc at https://help.libreoffice.org/Calc/Date_and_Time_Functions

Ref: Epoch date: January 1, 1970 --- Unix Epoch aka POSIX time, used by Unix and Unix-like systems (Linux, Mac OS X), and programming languages: most C/C++ implementations, Java, JavaScript, Perl, PHP, Python, Ruby, Tcl, ActionScript. Also used by Precision Time Protocol.

Ref: Pythagorean theorem at https://en.wikipedia.org/wiki/Pythagorean_theorem