Georeferencing a CAD Drawing

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03-03-2011 08:20 AM
LaurieMeineke
New Contributor
I have been trying to georeference a Cad drawing to match my raster.  When I use the Georeferencing toolbox, the CAD drawing does not appear as a target layer.  I used the tool CAD to geodatabase to load the CAD into ArcSDE.  It adds to the map fine, but why can I not see it in the layer box to georeference it?  If I add the raster to my map, that file will appear, but not the CAD drawing?????

Can someone help me?

My goal is to overlay the CAD drawing over the aerial.
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11 Replies
DakeHenderson
New Contributor III
Yes I believe Georeferencing is for rasters & Spatial Adjustment is for other features.

In my quest to do the same thing, even with Spatial Adjustment the features would NOT move.  So, ESRI Support told me:

The following steps help to fix the issue:
1. Create a Feature class in the Geodatabase with unknown spatial reference.
2. While creating the feature class import the fields from the original feature class.
3. After creating the feature class right click on the feature class and assign the projection by importing the desired projection.
4. Right click on the feature class and then click on Load > Load Data.
5. Select the feature class to from which you need to load the data.
6. Create another feature class in similar manner.
7. Register the feature classes as versioned.
8. Start Editing and make sure the editing templates are created visible in edit session.
9. Create four or more control points and adjust the data.
10. This would adjust the data spatially.

Also, for doing any editing in SDE Geodatabase, the feature classes and the data set have to be registered as versioned.

Good luck.


    Georeferencing a CAD file is perfectly good practice.  In ArcGIS 10, I've found I'm sometimes prompted to create the WLD file, sometimes not.  In either case, one is created in the same folder, and with the same file name (plus .WLD), as the CAD file (use Windows Explorer to check).  If the WLD file is present in the same folder as the CAD file, the CAD file will display in it's proper location. If you use ArcCatalog to copy a CAD file from one folder to another, the WLD file (if present) will be copied along with it automatically. Other than the file extension, the file names must be exactly the same.
    I've never had trouble seeing the CAD file's layers names in the Georeferencing Toolbar/ Layer box (you only need to pick one layer to georeference the whole file).  But I still get CAD files from a particular surveyor that simply wont rregister properly, I don't know why.
    It's considered best practice to create a PRJ file (define a projection), and I guess it would be necessary for loading into SDE.
    You may want to check out this 72 min video: http://video.esri.com/watch/666/using-cad-data-in-arcgis
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DiyaChowdhury
New Contributor
Hello,

I recently switched to mapping in Arcmap. To begin mapping, I created a geodatabase with various feature classes, all georeferenced to the co-ordinate system of the basemap. However when I first began mapping, I used the georeferencing toolbar to rotate the basemap ONLY. I have been mapping for a couple of weeks and it just occurred to me that all of the mapping I have done so far is georeferenced to the basemap but rotated by 180 degrees! I saved the entire project as an .mxd project but everytime I try and add the feature classes to the basemap separately they are off by 180 degrees. This becomes an issue when I use basemaps covering the same aerial extend but different resolutions etc, ie- my mapping is not georefernced correctly.

Does anyone know of an easy way to fix this? I have tried converting the geodatabase to a raster and rotating it etc, but they are still not alligned with the features on the basemap as before.

-Diya
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