[Qgis-user] Batch convert nonsense-coordinates from DWG?

[Bernd Vogelgesang]

Hi Nigel,

the problem in my field, ecological impact surveys for construction 
related projects (solar/wind parks, street construction, etc.) is the 
way, projects are handled in general:

Some project manager asks you for some task in a certain area.
The normal case how I receive basic geographical data in this phase:

a) Screenshot of google maps or same other map service, with either 
drawn polygons and some text annotations or just freehand drawings on them.
b) A pdf with the CAD data with no areal image background, so just 
colours vomited on white background

c) a DWG with ALL project related data, or even with additional 
non-project related data cause the CAD guys just reused some old project 
template and didn’t bother to remove the leftovers.
  c1) The DWG is in a too new format, so QGIS won’t import it → trying 
ODA file converter
  c2) The DWG will import but as none bothers to tell me the CRS, it 
takes hours of trial-and-error import the always 100 to 200 layer groups 
into QGIS just to find out that they didn’t use any CRS.

To ask the project managers for usable data is completely useless almost 
all cases, cause not a single one has an idea what I am actually talking 
about.
In addition to that, it is most likely impossible to get direct contact 
to the CAD guys cause either the managers have no idea where the data 
came from or they simply just won’t let you get in direct contact with 
their CAD guys. (I managed to do that once in the last 10 years)

Besides that I simply do not see the point in using CAD for geographic 
data, I am sick and tired of asking back all the time, explaining data 
formats and coordinate systems.

The domination of mediocrity and incompetence is so frustrating.

Am 04.06.25 um 09:04 schrieb Nigel Berjak - General:
> Hi Bernd
> 
> Yes, I receive CAD files all the time with it being 'georeferenced' but 
> actually they sometimes only include a grid overlay with coordinates and 
> nothing more. What I do and what I would suggest is importing the entire 
> CAD file into a Geopackage or File Geodatabase, then re-georeferencing 
> all layers/information within the file (I think you can do it using all 
> layers) concurrently to assign the correct coordinates and ensure that 
> the correct EPSG/ESRI CRS is assigned.
> 
> The other option is to request from the CAD guys a KMZ of the file, 
> which they seem to be able to output in the correct location, and rather 
> use this. You can then, if they have any attribute data embedded as a 
> description field, expand that using the KMZ plugin.
> 
> I hope this assists you.
> 
> ---
> Regards,
> 
> Nigel Berjak
> Please consider the environment before printing this email.
> 
> On 2025-06-03 20:31, Bernd Vogelgesang via QGIS-User wrote:
>> So now I tried the import with EPSG 5653 and this one seems to work.
>>
>> I am working now with geodata for around 15 years, but the CAD scene 
>> never runs out of new obstacles for me.
>>
>> What the f is EPSG 5653, and most importantly: Why is it it even being 
>> used?
>>
>> (Fun fact: once a CAD guy told me, after me complaining about his data 
>> having just some local cartesian coordinates and no official CRS, that 
>> his software would run much slower, the higher the coordinate numbers 
>> were, so working with short local coordinates was his way to be able 
>> to work at all.
>> Now these other guys just add another 2 digits? Obviously trying to 
>> evade work!)
>>
>> Did I already mention that I very much dislike CAD and its seemlingly 
>> not existing philosophy behind it.
>>
>> Thanks for the hints!
>>
>> Bernd
>> Am 03.06.25 um 17:10 schrieb Jürgen E. Fischer via QGIS-User:
>>> Moin Bernd,
>>>
>>> On Tue, 03. Jun 2025 at 16:25:54 +0200, Bernd Vogelgesang via QGIS- 
>>> User wrote:
>>>> Actually, the data should be in EPSG 25833, but somehow they managed to
>>>> scramble the x-values by adding 33 before the otherwise correct 
>>>> coordinates.
>>>
>>> So EPSG:5650?
>>>
>>>
>>> Jürgen
>>>
>>>
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-- 
Dipl.-Geogr.
Bernd Vogelgesang
Kappel 17
91355 Hiltpoltstein
Tel: 09192-3499427
mobil: 0163-1860160
mail at berndvogelgesang.de