shrug-l: survey data

Tripp Corbin tcorbin at
Wed Sep 30 10:53:42 EDT 2009


All that message means is that there is not a prj file associated with
the CAD file which tells ArcGIS what projection and coordinate system it
is in. It does not mean that the coordinates stored in the CAD file are
not in your desired coordinate system. So you are fine. You might want
to look at an article I wrote on our website about understanding the DWG
format for a better understanding of DWGs and DXFs.  Here is the link:



Tripp Corbin, MCP, CFM, GISP
Vice President, GIS/IT
ESRI Authorized Instructor
Keck & Wood, Inc. <> 
(678) 417-4013
(678) 417-8785 fax


From: shrug-l-bounces at
[mailto:shrug-l-bounces at] On Behalf Of Hunter,
Sent: Wednesday, September 30, 2009 7:17 AM
To: SHRUG-L at
Subject: shrug-l: survey data
Importance: High


Good morning, all.


   I have a question regarding CAD data (.dwg and .dxf) files.  When I
bring CAD data into a new ArcMap session I get a message that says:


    Unknown spatial reference:


      The following data sources you added are missing spatial reference
information.  This data can be drawn in ArcMap but cannot be projected:

                            126.dxf  Group Layer


    However, when I bring another shape file in the session to see if
the CAD file is in the correct place, the file is in the correct place.
I have a process which I must follow, (SOP - Standard operation
procedure), so this message is one I need to understand so that I can
explain it to the surveyor's CAD person.


    Any help or ideas would be greatly appreciated.




Blessings on your day.


Virginia (Ginny) Hunter

GIS Analyst I (LA&M)

Suwannee River Water Management

Live Oak, FL  32060

1-800-362-1001 ext. 3140

1-800-226-1066 (In Florida)






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