AutoCAD Map 3D General Discussion

AutoCAD Map 3D General Discussion

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ericcollins6932
Posts: 334
Registered: ‎05-13-2010
Message 1 of 2 (635 Views)
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Civil 3D 2012 Coordinate system scale factors are wrong?

635 Views, 1 Replies
01-02-2014 10:31 AM

I was recently setting up a new install of Civil 3D 2012 and was going to set the default coordinate system to 3TM (CM=114°W) when I realized the scale factor was set to 1.0 at the central meridian.

 

It should be 0.9999. I checked some others and they are all the same. I also checked the 6TM projection and it is also set to 1 although it should be 0.9992

 

Below is the WKT(ESRI) out of Civil for EPSG code 3401:

 

PROJCS["CANA83-10TM115",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.000,298.25722210]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",0.000],PARAMETER["False_Northing",0.000],PARAMETER["Scale_Factor",1.000000000000],PARAMETER["Central_Meridian",-115.00000000000000],PARAMETER["Latitude_Of_Origin",0.00000000000000],UNIT["Meter",1.00000000000000]]

 

Looking up the .PRJ for EPSG 3401, the published standard is:

PROJCS["NAD83 / Alberta 10-TM (Resource)",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",-115],PARAMETER["scale_factor",0.9992],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["Meter",1]]

 

Is anyone aware of this behaviour in version 2012? Has it been fixed in later versions? Thanks in advance.

 

 

Eric Collins, P.Tech.(Eng.)

Win 7 Enterprise SP1 64 bit
Intel i7 3770 @ 3.40 GHz
16 GB RAM
Civil 3D 2012 SP2

This issue was fixed in Civil 3D 2013. These can be verified using MAPCSASSIGN, finding the appropriate Coordinate System [CANA83-3TM114 in this case] then using the View option at the bottom [between Assign and Close], and then select -Projection on the left side. In Civil 3D 2013 and 2014, the scale reduction is listed as .9999.

 

This same process in Civil 3D 2012 up to and including Service Pack 4 still gives the wrong scale factor of 1 for this Coordinate System.

Product Support
Willy_Campbell
Posts: 46
Registered: ‎07-12-2013
Message 2 of 2 (565 Views)

Re: Civil 3D 2012 Coordinate system scale factors are wrong?

01-08-2014 02:57 PM in reply to: ericcollins6932

This issue was fixed in Civil 3D 2013. These can be verified using MAPCSASSIGN, finding the appropriate Coordinate System [CANA83-3TM114 in this case] then using the View option at the bottom [between Assign and Close], and then select -Projection on the left side. In Civil 3D 2013 and 2014, the scale reduction is listed as .9999.

 

This same process in Civil 3D 2012 up to and including Service Pack 4 still gives the wrong scale factor of 1 for this Coordinate System.



Willy Campbell
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