Question

Coordinate System Issues with AutoCAD Map 3d to .GDB Translation

  • 10 June 2013
  • 4 replies
  • 5 views

Hi,

 

I'm a very new FME user attempting to convert a .dwg file without a coordinate system into Geodatabase files. Every attempt so far has resulted in feature classes that are entirely unallgined with the basemap. The extent values are in the millions of decimal degrees. Obviously there's something i'm missing. Any input would be greatly appreciated. Thanks.

 

 

-Tim  

4 replies

Userlevel 3
Badge +13
Hi Tim,

 

 

If I understand you correctly and you are reprojecting, there is a transfomer to do reprojections using the ESRI library (ESRI Reprojector), also the tolerance of in and output can be in these cases of importance.

 

Hoep this helps.

 

 

Itay

 

 

 

Thank you for the very prompt response. Unfortunately the ESRI reprojector transformer only resulted in a massive polygon, point cloud and line network that covered the entire western hemisphere(i'm working woth about 20 square miles of telecom exchange data). Another issue i ran into with the reprojector was with the specification of the input coordinate system. Unfortunately when the cad file was composed it was done so in cartesian coordinates. The closest to success i've had has been when FME recognized a .wld file from a previous, but flawed manual arc gis georeferencing attempt, which results in the network data being placed about 20 decimal degrees north of its proper location. I apologize if this is difficult to understand, i feel like the answer shouldn't be as it should seemingly be the most basic FME operation. let me try and restate it: I'm trying to use FME to get a AutoCad Map 3D 2009 map(with no coordinate system) into Arc GIS. All input is greatly appreciated, thank you.  
Userlevel 4
Hi,

 

 

these types of reprojections might seem simple, but then again they might be complicated in practice, very much depending on how the drawing was created. So it is difficult to give specific advice on this matter.

 

 

However, in general I would suggest something like

 

  1. CoordinateSystemSetter that corresponds with the coordinate system used in AutoCAD
  2. Either the ESRIReprojector or the CsmapReprojector to transform to the desired coordinate system in the GDB
  3. If necessary, using an Offsetter and/or a Rotator to nudge the result into place
I'm sure there are other ways, but I hope it can help you get started.

 

 

David
I've tried the various reprojectors suggested and various other means of assigning projection systems, but the problem remains that while my units have changed from arbitrary cartesian coordinates in feet to decimal degrees, their respective values haven't shifted(they're still in the millions of decimal degrees). Is there anything i'm missing or a general procedure for dealing with cad files lacking coordinate systems? I apologize for drawing this out, all the support has been incredibly welcome and very much needed. Thank you.

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