[Qgis-user] Georeferencing dxf file in QGIS

[Linda Boisvert]

Thank you Richard. Your suggestion was a step in the right direction.

I had to import using the add vector layer then export as an ESRI shapefile
and add the shapefile layer. That put all the features from the multiple
dxf file layers on one layer and I was able to move the design. But it is
important the keep the dxf layers separate and move the whole group of
layers at once to maintain the relationship.

On Tue, May 14, 2024, 2:26 PM Richard Greenwood <richard.greenwood at gmail.com>
wrote:

> You can just use the QGIS *Move Feature* tool, possibly in conjunction
> with the *Rotate Feature* and/or *Scale Feature* tools in the advanced
> digitizing toolbar.
>
>    1. Assign a coordinate system to the DXF layer. If you don't know the
>    coordinate system, or if the DXF file doesn't have one, assign the
>    coordinate system of your reference layer (your aerial photography)
>    2. Make your DXF file editable. Depending on how you imported it you
>    may be able to make it editable, or you may need to copy all of the
>    features to an editable work layer.
>    3. Select all of the features, pick the *Move Feature* tool, pick a
>    source point on a corner of the building, pick a destination point on the
>    corresponding corner in your reference layer. (this takes some serious
>    panning and zooming!)
>    4. With all of the features still selected, pick the *Rotate Feature* tool,
>    while holding the Control key click the building corner to fix the rotation
>    base point, then click two more points to define the rotation angle.
>    5. You may need to scale it e.g. convert feet to meters. If so, pick
>    the *Scale Feature* tool, hold the Control key and click a base point,
>    then two more points to resize all of the features.
>
> The move, rotate and scale steps are performing an affine transformation
> which should provide reasonable results over small areas if both the DXF
> and reference layer are in projected coordinate systems, ideally local
> projected coordinate systems like State Plane or UTM, and not Web Mercator.
>
>
>
>
>
>
> On Tue, May 14, 2024 at 3:00 PM Linda Boisvert via QGIS-User <
> qgis-user at lists.osgeo.org> wrote:
>
>> Hello,
>>
>> I have been trying to georeference a dxf file created by a solar design
>> software.
>>
>> I can import the file without issues but the design sits in the middle of
>> the Pacific Ocean. I have georeferenced rasters before but I can't get this
>> dxf file to budge.
>>
>> I have tried many of the suggestions I have found online for
>> georeferencing the dxf file.
>>
>> I have tried to move the design using QAD and QAD did not find objects
>> when I tried to select the design or any single line.
>>
>> I imported the file into LibreCAD and the file worked fine in that
>> software.
>>
>> I imported the file into ArcGIS and I could not see the lines of the dxf
>> file.
>>
>> I have attached a test dxf if someone wants to try it out and find a
>> solution. The building is the Eugene Brucker Education Center 4100
>> Normal Street San Diego, CA 92103.
>>
>> Does anyone have any suggestions for georeferencing this file or any idea
>> what the issue may be?
>>
>>
>>
>>
>> --
>> Sincerely,
>> Linda Boisvert
>> _______________________________________________
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>> QGIS-User at lists.osgeo.org
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>
>
> --
> Richard W. Greenwood
> www.greenwoodmap.com
>
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