[Qgis-user] How set real origin on a false origin dataset

[Alexandre Neto]

Hi,

Another possible solution it's to create a custom projection where you
include the false origin information (false northing and false easting.
Then set your layers to use that custom projection.

For more information on how to create a custom projection in QGIS, check
this page of the official documentation:

https://docs.qgis.org/3.4/en/docs/user_manual/working_with_projections/working_with_projections.html#id12

For more information about the false northing and easting, check PROJ
documentation:

https://proj.org/usage/projections.html?highlight=false%20north#false-easting-northing

Alexandre Neto
QGIS Support
www.qcooperative.net



A domingo, 17/11/2019, 10:10, Lens Paul <paul.lens at gmx.com> escreveu:

> Hi Andrea,
>
> False origins happens often with local topographical surveys, with also a
> false altitude origin. Architectural plans are sometimes even more tricky:
> rotated, or with a centimetric or millimetric scale instead of a metric
> scale. A way is to transform the data with a CAD software when available.
> Even then, problems can arise e.g. when rescaling some objects.
>
> I suppose a workaround in your case  would be to use the "move" command
> and to snap to a point drawn at the correct coordinates. This could be
> cumbersome when there are many layers to edit, which is often the case,
> unless you import the dxf as a unique layer....
>
> If your data consist merely of point data (no polylines), it should be
> possible, after conversion of the dxf in a shapefile, to create the  X, Y
> attributes using the field calculator, and to recalculate these attributes
> with the same tool.
>
> In the case of polylines, there is the possibility to extract vertices.
> But I do not know if there is a possibility to recreate the polylines after
> the recalculation of the X, Y attributes.
>
> Dxf conversion is a complicated subject. The evolution of the capabilities
> of QGIS in that field is amazing. Many thanks to the developers for that.
>
> Hope this helps,
>
> Paul
> Le 13/11/2019 à 14:04, Andrea Peri a écrit :
>
> Hi,
> We have a dxf containings geograph data in false.origin .
> I'm searching a solution to put a kind of origin (x,y) to sum to every
> point of the data. Is possible to set an origin.to a dataset in qgis ?
>
> Thx.
> Andrea.
>
>
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