Hello.

Good day Brynn. I understand that https://inkscapecommunity.com and yourself moved to https://inkscape.org . Once again, thanks a lot for your very usefull tips at the begin of this year, regarding my drawing of a compass rose.
If I understand well, https://inkscape.org/forums/ is a forum only in English, isn't it ? No forum in French ?

For purpose of comparison, I would like to test the drawing of a 2D architectural plan with Inkscape; the Inkscape v.0.92 already installed on my PC. For instance to draw the floors of my house. In the canvas, I'm using the A4 page in the landscape position. Zoom is set to 69 % so that this page occupies the entire high of the canvas.
The dimension of my site is 27m00 x 10m00 and the usable width of the A4 is a. 270 mm. So, the scale that I need is of 1cm on drawing by 1 m in reality = 1 %.
In the dialog box 'File > Document Properties', I first put the 'Page Size' parameter to A4.

If I had been able to set 'General > Display units' to m, I had put 'Scale x:' to 1.0 ('User units per cm' / uniform scaling) in 'Scale'. For instance 27 cm on the A4 drawing corresponding to 27 m in reality. Unfortunately, as it is not possible to set 'Display units' to m - at the most cm . So I expected having to put 'Scale x:' to 100 (or to 0,010).
I have drawed a rectangle whose width is slightly smaller than the usable width of the landscape A4 page. Surprise : The width indication in the bar under the canvas displays 27,0 and not the expected 2.700,0 (cm = Display units).
As Display units has to be set to cm (and not m as I had preferred), how can I get 2.700 ?

PS: Incidentally, please recall me the right command to shift my rectangle so that its center corresponds to the one of the A4 page in the canvas.

Hi Chavadam.  This forum is primarily English.  Occassionally we may have someone show up who can answer in other languages.  On the Community page, this is listed as a French language Inkscape support forum.  http://www.linuxgraphic.org/forums/viewforum.php?f=6   I don't know how active it is (since I don't read French, I haven't visited it). But your English seems fine to me  🙂

I'm flattered that you remember me, and I do remember helping with the compass rose.  Do you mind if others contribute to answering your questions here?  I am terribly confused by that Scale setting in Document Properties, and other members here will be much more helpful.  In general, I always advise users not to change the Scale setting in Document Properties.  For the most part, it should only be used by people who know what it's for, how it works, and know what they're doing.  (And that's not me, haha!)

To put it back where it should be, follow this routine:

• Set Display Units to px
• Set Scale to 1.0
• Switch Display units back to cm
• Don't change the Scale setting anymore (yes, it's supposed to change when you change the units)

For myself, I would replace the Scale setting to normal (as steps above), and just draw in cm.  If you do that, then the rectangle would show the correct size.  I suspect that Scale setting might not do what you think it does (although I could be wrong).  I don't think Inkscape has the ability to change the scale, in the way that you're thinking.

There are a couple of Inkscape extensions which can change the scale.  So you could draw in Inkscape, and then use an extension to change the scale.  One of them can take your drawing, no matter what size the objects are, and change it to real life values.  Then you wouldn't have to mess with the Scale setting.  https://github.com/Moini/inkscape-realscale-extension/   (https://inkscape.org/en/~Moini/%E2%98%85realscale-resize-by-line-of-known-length)    I'm not sure if I can find the other.....  Edit - I found it, but doesn't sound like what you need.

However (since I don't understand it very well) it's possible there is some way you could use the Scale setting, for your purpose.  Someone else would have to tell you how to do it, if it's possible.  (I could give you my best guess, but better to get the answer from someone who isn't guessing  😉 )

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To center the rectangle on the page, there are probably a few different approaches.  One would be to use math, and set the rectangle at the proper x,y coordinates, using Selection tool, and X and Y fields in the control bar (just above horizontal ruler).  Or maybe more quickly, select the rectangle, then

• Object menu > Align and Distribute. 
• Set Relative to: dropdown menu (at the top of the dialog) to Page
• Click Center on Vertical Axis button
• Click Center on Horizontal Axis button

(Sorry, we don't have Inkscape icons here, or I would show the buttons.)  I just tried snapping, but apparently snapping to page center doesn't work (at least not in 92.3)

If you set units to cm and the scale to 0.377953, you should see something similar to this:

Hello Brynn and Tyler Durden.

Many thanks for your time and efforts trying to give me good advices.

Meantime, I found another 'Scale %' parameter in the Measurement Tool. Putting it to 10000.00 % make that the measurements appearing on the drawing do correspond to 2698,01 cm (= ± 27 m), what I need, except the little conversion error ...

Without any pretention, I thing that this 'Scale' topic may be subject to an amelioration by Inkscape, is it only the explanation in the tutorials.

Thanks a lot.

You might avoid rounding-error using the method I posted above. My suggestion is a workaround that will allow use of the measure tool with precision, or use of traditional drafting tools on paper prints (if the printer is accurate).

At one time, Inkscape may have included cm units, but no more.

Custom units can be set in the units.xml file.