Georeferencing CAD (dwg) files

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08-05-2022 04:51 AM
by Anonymous User
Not applicable

After defining the projecting of my .dwg using the define projection button in the Manage CAD layer tab the output is as shown in the attached image.  As you can see the polyline features are in the top left corner however the centre of the feature is as shown by the yellow dot and border. 

This makes scaling, rotating and position difficult. I wondered if this was a known issue or if it is something to do with my input .dwg?

If I use the CAD to geodatabase tool the issue is resolved. However I am then unable to use georeferencing to position the output, only scaling, rotate and move in the editing tab.

I am also having issues placing control points with this particular project, after placing 3 or so the option to place any further points is greyed out. Again is this an issue anyone else has encountered?

 

Thanks in advance.

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4 Replies
PROBERT68
Frequent Contributor

You need to use the imagery basemap first where you will be using your control points in that area.  Find the basemap and then try your best  to zoom in a bit and then use the "Move the Display" . If it shows up then you can use the scale, rotate, etc easily.

In that picture you showed us, there is no imagery basemap ? Just white background.  It means it is somewhere ....

Here is an example.  

Screenshot 2022-08-05 134559.png

Also, it is up to you if you want to bookmark of your CAD in case .

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by Anonymous User
Not applicable

Hi PROBERT68,

Thanks for taking the time to respond. The issue with georeferencing has not been resolved by adding a base map, I often work without one. I am using polygon features as targets for the referencing and I am still unable to add more than 3. Fortunately I am able to get the CAD polylines into a fairly good position manually, although this is less than ideal and seems like it should work. Which is why I'm wondering if it's an issue with my dwg files or something else.

I've attached two further screen shots to try and explain my other issue as I may not have been totally clear in my first post. 

CAD_to_Geo shows the centre of the feature at the centre of the polylines where I would expect it to be, making manipulation easy and is the output of CAD to geodatabase tool.

CAD_LYR_Manage shows the centre of the feature in a totally different position and is the result of define projection in the CAD Layer Manage Tab , making scaling etc very difficult. Again, I wondered if this is something I've done wrong, a known issue or an issue with my dwg's?

Thanks

Matt

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PROBERT68
Frequent Contributor

Your welcome.  I have no clue what you were trying to do without a  basemap .  How is possible for you to get your CAD in a fairly good position with no  basemap  background ? is there some reason for your side to do this your method without it ?

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by Anonymous User
Not applicable

Hi

The polygon features I am using as targets are in the correct position, so I either bookmark them or use a marker.

Thanks 

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