Georeferencing with Design Layer Viewport References

[lisagravy]

I have two files containing baseline information for my project - Topographic Survey and Architect's Layout.

 

Both have been imported from DWG into their own new VW files, and georeferenced according to the procedure detailed in the previous georeferencing thread on this forum. I can Geo-image in both of these files and the drawings fit beautifully over the site.

 

I now want to reference the information in these drawings into a new master file, using the design layer viewport referencing system, so that I can use the information to inform my own drawing. However, when I try to do this... while the X Y positions of the drawings remain correct, the GIS stake shows that the design layer viewport referenced layers, when created, are nowhere near the geo-located positions set in their original files. 

 

Am I missing something really straightforward? Any help much appreciated. 

[Tamsin Slatter]

Hi Lisa

I'll look into this for you... 😀

[lisagravy]

🙈 Thanks @Tamsin Slatter - I must be your most irritating customer at the moment! Everyday a new georeferencing query 😂

[David S]

That's my job 🙂

 

[Tamsin Slatter]

1 hour ago, lisagravy said:

🙈 Thanks @Tamsin Slatter - I must be your most irritating customer at the moment! Everyday a new georeferencing query 😂

Not at all! I LOVE your questions.

[Tamsin Slatter]

Hi Lisa

Just checking in to let you know I'm working on this. In my findings, so far, I ref in the first design layer viewport, and it lands in the correct place. Then I ref the second, and it lands in a different place—but seems to be relative to the INTERNAL origin. In my ref files, I was sloppy about the positioning of the INTERNAL origin (just put it close to my geometry - not in a specific location). And in my target file, I didn't move the internal origin at all. I'll keep working on it, and I have booked some time with the engineers to discuss, but I just want to check in to let you know I haven't forgotten you.

[lisagravy]

Thanks @Tamsin Slatter ☺️ Much appreciated! 

[Tamsin Slatter]

OK - I'm stumped. Definitely one for the engineers. I'll keep you posted.

[Tamsin Slatter]

OK - I've got it to work. Referring to our other post (linked above) I've done the following:

 

Create File One Ref

1. Open blank file and ensure Georeferencing is set to EPSG 27700.
2. Import DWG (in my case topo of Exeter in OS British National Grid X and Y coordinates). This file has the largest extents of geometry of my two reference files.
3. Geolocate the internal origin to a known point on the imported geometry.
4. Add a GIS Stake to show E and N in Meters of this point. It is important that the internal origin is in the same location within the geographic coordinate system across all files.
5. Run the new Align User Origin with Georeferencing Coordinate System (coming soon in SP2 - but refer to steps in linked post for SP1 method).
6. Now, the User coordinate system is aligned with the Georeferencing Coordinate System and the internal origin is in a known location within that coordinate system.

Create File Two Ref

1. Open blank file and ensure Georeferencing is set to EPSG 27700.
2. Import DWG (in my case a detail area of Exeter, still in OS British National Grid X and Y coordinates). This file has the smaller extents of geometry of my two reference files.
3. Run the new Align User Origin with Georeferencing Coordinate System (coming soon in SP2 - but refer to steps in linked post for SP1 method).
4. Add a GIS Stake to show E and N in Meters of this point. Change the X and Y coordinates of this stake to the same as the location of the internal origin in File One above.
5. Geolocate the internal origin onto the Stake created above. The internal origin is now in the same location as in file one.
6. Now, the User coordinate system is aligned with the Georeferencing Coordinate System and the internal origin is in a known location within that coordinate system.

Create Target File Three

1. Open blank file and ensure Georeferencing is set to EPSG 27700.
2. Create two design layers.
3. Edit each Design Layer and check Georeferenced, to ensure that they are both georeferenced according to the document.
4. Run the new Align User Origin with Georeferencing Coordinate System (coming soon in SP2 - but refer to steps in linked post for SP1 method).
5. Add a GIS Stake to show E and N in Meters. Change the X and Y coordinates of this stake to the same as the location of the internal origin in Files One and Two above.
6. Geolocate the internal origin onto the Stake created above. The internal origin is now in the same location as in file one and two.
7. Now, the User coordinate system is aligned with the Georeferencing Coordinate System and the internal origin is in a known location within that coordinate system.
8. On the two design layers you created above, create design layer viewports of files one and files two.
9. In my testing, the files line up perfectly.

I hope this helps.

Archive.zip

[lisagravy]

@Tamsin Slatter - amazing! Thank you.

[lisagravy]

@Tamsin Slatter - just working this through on a new file, and while it will work a dream in SP2... there are a few extra steps for the SP1 method.

 

Reason being - if I have Target File 3 as a blank file, without the SP2  'Align User Origin with Georeferencing Coordinate System' dream tool, I can't locate a GIS stake in the same location as the Internal Origin of the xref files, because my XY don't align yet so I don't have any way of positioning it.

 

I have to use the search geolocate function to find the site, then geolocate on a random point - then set the user origin manually to align with the co-ord system to allow me use of the XY positioning.

 

Then I can set a stake tool with the same co-ordinates as the Internal Origin for other files, and geolocate again to this point.

 

However, this messes up the user origin again as it's position is set in relation to the Internal Origin... so I have to set the User Origin back to the position of Internal Origin, before I can reset the user origin manually again to align with the co-ord system.

 

It works, but it's convoluted! When is SP2 coming out again?? 🤪

[Tamsin Slatter]

I don't have an exact date for you... but I *think* it will be this month... But don't shoot me if I'm wrong!