Export vector layer in DXF with systematically metrical system unit?

Question

As said on this page https://gdal.org/drivers/vector/dxf.html,

GDAL writes DXF files with measurement units set to “Imperial - Inches”. If you need to change the units, edit the $MEASUREMENT and $INSUNITS variables in the header template

$MEASUREMENT and $INSUNITS are the variables in Autocad in order to choose between an imperial and a metric system.

As I never use the imperial system, is it possible to configure Qgis in order to systematically export vector layers in DXF format with a metric system? I precise that my Qgis is configured with the language, numbers, date and currency formats from the US).

I totally agree with the fact that this is not a big problem, but I have the feeling to lose so much time everyday just to change the unity from the imperial to the metric system in Autocad.

I think it would be interesting in the future to let that choice to the user in the "Save Vector Layer as ..." window...

Answer 1

I finally figured out what meant "edit the $MEASUREMENT and $INSUNITS variables in the header template".

The header template is located here: C:\OSGeo4W\apps\gdal\share\gdal\header.dxf

This is an ASCII DXF file that contains the variables $MEASUREMENT and $INSUNITS. Originally, these variables are :

$MEASUREMENT
    70
         0
      9

and

$INSUNITS
 70
     1
  9

which correspond to the imperial units. According to the documentation for $MEASUREMENT and $INSUNITS and with the help of a text editor, I changed the parameters to :

$MEASUREMENT
 70
     1
  9

and

$INSUNITS
 70
     6
  9

Unfortunately, this solution only works for data exported layer by layer (and not by Project>Import/Export>Export Project to DXF...).

If someone has an idea about it, I'll take it.