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lisagravy

Georeferencing settings

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This is a very interesting too indeed.

 

I tried to use it last week but due to the time pressure and a vague clue on how to use it I decided to give it ago another time.

What I managed to check on my drawing was the alignment with the ortophotomap underlay. They seemed to be miles away. I understand that I need to align my UCS with the GCS.

Again I understand that in VW, an imported dwg file retains its NE coordinates from the survey but is just centered on the drawing space.

There are geodesic station points with [lat lon] coordinates on the topo survey drawing, therefore I should be able to use these for georeferencing, correct? 

Should that be done through the Document Georeferencing or one should change the internal origin first?

Any step by step walktrough?

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Here's my high level overview.

  1. Open blank document.
  2. Edit document georeferencing settings and choose the appropriate geographic coordinate system. If you are in the UK, the standard UK templates are automatically set to 27700 which is the geographic coordinate system equivalent to the OS British National Grid. On this dialogue, the coordinates at the top relate to the position of the file's INTERNAL origin, within that coordinate system. In a UK file, we set this to the Greenwich Meridian as a default. This can be changed.
  3. Import the DWG file, but use the checkbox This file contains georeferenced geometry. Click the Advanced button and take a look at the GIS tab - this will confirm that the DWG will be brought into the georeferencing settings set at the document level. Click OK and again to complete the import. 
  4. The geometry will land in the correct place within the GIS system (as long as it was actually created in the correct place in the first place.)
  5. Use the Geoimage tool and draw a rectangle around the site. This will load the imagery associated with the site.
  6. Use the Geolocate tool and click on a location on the site to move the internal origin close to the geometry.
  7. From this point on, X and Y are no longer relevant, and you should use Easting and Northing instead. The GIS Stake tool can be used to report these.
  8. If you want the numbers on the User Coordinate system to match, use Tools > Origin > User Origin. Choose the option to Set the user origin to match the origin of the geographic coordinate system.

Why might it not work?

  • Your DWG is not created in the same coordinate system as the GIS coordinate system.
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Hi,
I am having trouble getting the GeoImage function to correctly place the satellite view behind my OS plan. I have imported the OS DWG (location  in south of England near Gatwick airport) with Geolocation on and the Lat/longs + OS grid are reading correctly with the document grid(see 1st screen shot). I have checked the lats/longs VW is giving, in Google earth and they are correct. When I turn Geoimage on it thinks I am in Germany near Hamburg see second and third image (red dot is my OS blue cross hair is site location). I have checked geo referencing settings and believe they are correct (see image 4). Any ideas please?

Screenshot 2020-02-28 at 11.00.33.png

Screenshot 2020-02-28 at 11.00.44.png

Screenshot 2020-02-28 at 11.01.00.png

Screenshot 2020-02-28 at 11.09.18.png

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@adam covell I think this is because your user origin and GIS settings don't tie up.

 

An easy way to check is to go to Tools > Origin > User Origin, and select "Set User Origin to match the Georeferencing Co-ordinate system". This will change the document grid to match the georeferencing co-ordinates and show that the grid of your drawing is actually in an incorrect location in geo-referenced terms?

 

The reason for this is that British Grid is set up using an agreed origin point off the coast of the Scilly Isles, and all co-ordinates are measured by Easting and Northing distance from that point. Vectorworks origin (both Internal and User) default to a location in Greenwich Park - so you want to reset your ruler to the actual British Grid 0,0 point, otherwise your drawing will sit geographically approx 539000m east and 177200m north of where you think it is.

British Grid.jpg

Edited by lisagravy
Additional info and image attached.
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Thank you. I have just tried that and that does change the origin (it no longer matches the OS grid) but when I use the Geoimage tool I am still in Germany (it has not repositioned the image).

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No worries @adam covell . Yes your drawing is in the wrong place unfortunately - it is in Germany. The user origin doesn't affect the position of the drawing in GIS terms,  but rather just whether what you see on the rulers is correct / makes sense.

 

If you open a blank file, set the user origin to match the georeferencing settings, and re-import the OS dwg - but make sure you tick the 'this file contains georeferenced geometry' box on import.

 

This should import it in the correct place, on both the rulers and the geo image.

 

(Note that if you then use geolocate to position the internal origin on your site (which you should do), you'll have to reset the user origin again to get it to match the easting and northing co-ordinates again. It won't affect your positioning though.)

 

 

Screenshot 2020-02-28 at 14.14.37.png

Edited by lisagravy
Tagged user in reply. Additional note on geolocate.

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thank you @lisagravy . i have gone new - blank document, origin - set user to match the georeferencing coordinate system. then imported a different topo that has been georeferenced (i have used your settings as above - this file contains geo referenced geometry ) . Again it matches with VW axis grid correctly but I go to geoimage and it shows me this time, Greenwich park.

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@adam covell Ok. So I've done the same thing with a blank file just to check I'm not missing anything, and mine is working.... here are my steps.

  • Blank document.
  • Check the georeferencing settings are on (File > Document Settings > Georeferencing) - they should be on by default.
  • Origin > User Origin > set user to match the georeferencing system.
  • Check the design layer settings to make sure the layer is also ticked as georeferenced? (This shouldn't matter if you're ticking the georeferenced box on import as above, but worth doing in advance if you're having issues just incase! All new layers have to be set to this too.) 
  • Import DWG with "This file contains georeferenced geometry" ticked. (Units should be in metres.)

You should on import get a blank screen centred on the INTERNAL origin, (blue crosshair thing,) which will still be at Greenwich Park in GIS terms, and you should have to fit view to objects to locate your imported information, which will be situated somewhere away from the internal origin.

 

You can check the geo image at this point and it should match your imported information - mine does.

 

Then, click Geolocate, and click a position on your site. All this does is move the internal origin from Greenwich Park to your site, but shouldn't affect the geo image if you try this again. It will move the user origin again though, so you should go to Origin > User Origin > Set user origin to match the georeferencing system again for completeness.

Screenshot 2020-02-28 at 14.48.24.png

Screenshot 2020-02-28 at 14.52.00.png

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hi @lisagravy. Thanks for the instructions but still getting the same thing. Have followed to  the letter and done quite a few times trying new things but cant seem to make this work. When I set up a blank doc I notice by default with geolocate on I am in Greenwich park. When i import file with geo locate on it is still not changing the geoimage or the lat long settings. I can kind of fix things by finding the correct lat long and entering it into the dec prefs but its not quite right. .. very strange. 

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@adam covell - last thing I've thought to check, just incase this is a difference between between Landmark / Architect? On import, if you click advanced at the bottom left? It gives you options for import location. 

 

The standard default for me is the top option (centre first import, align all subsequent). If you imported like this your drawing would centre on the aerial for Greenwich Park.

 

However, with the "this file contains georeferenced geometry" box ticked, my VW then only gives the bottom option as available - Align with internal origin. Maybe just make sure yours does the same?

Screenshot 2020-02-28 at 16.20.45.png

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You know what ... that worked !!!!!!!!... I thought I had tried all of these import options but clearly not. Many thanks and have a great weekend

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Thanks Tamsin. We met briefly at the Nurbs modelling course in Winchester , September last year . You talked about the georeferencing then and I have been keen to use it since.

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On 3/4/2020 at 8:12 PM, Tamsin Slatter said:

I'll be announcing the link to my upcoming webinar today, but to those who have asked for a tutorial, I'd like to point you towards this webinar which was run by my colleagues in the US, and can be found in Vectorworks University.

Hi Tamsin, any chance that your GIS: Combining Geographic Coordinate and CAD Data webinar will be uploaded to the VWU any time soon? Thanks.

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27 minutes ago, Tamsin Slatter said:

So, only a few business hours have passed since the webinar ran, but I can assure you that it's on the team's agenda for today. We'll do our best to get it done.

Sorry didn't mean to be pushy, I am simply at Australian time. Thanks Tamsin, hope all at Vectorworks UK are safe and sound. Looking forward to the training now we have all the time in the world!

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1 hour ago, Tamsin Slatter said:

No problem at all! 

The recording is here:
Vectorworks 2020 GIS Webinar from the UK

Enjoy.

 

Thanks for posting (and creating) this. I've been eagerly awaiting this webinar since the release of v2020 but never received an announcement. Is that because I'm in the US or do I need to changed my settings somewhere?

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thanks @Tamsin Slatter very useful webinar. I have since been using the shapfiles with GIS. I now understand that centremaps who supply our OS data can issue me with a shapefile at the same time ... so this all works well. I still have the "failed to download" error on the GIS imagery quite a lot. I have tried zoooming in and out and changing the resolution bat cannot get this one fixed.. maybe just me

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@Tamsin Slatter As a US customer, thanks for posting the link to the webinar.  I thought I should let you know that the link takes me to the presentation in a VW University page, but the course itself does not show up in the VWU course list.   I'll let you decide if this is a feature or a bug.

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