Drawing files assigned to invalid GIS coordinate system

[ceissler9A6GZ]

Hello, I an an ArcGIS Pro (GIS) User and don't know much about CAD, so I apologize for that.

I understand that many CAD drawings are in measuring units of inches or millimeters.

But, I have received a DWG file created in AutoCAD with an assigned GIS coordinate system -- but it is invalid (does not align correctly) because the measuring units are still in Inches. ...I know how to fix this in ArcGIS, but I'm wondering how this happened in AutoCAD in the first place..?

I ask because it is NOT possible to assign a GIS coordinate system in ArcGIS Pro with units in anything other than degrees, feet, or meters. ...Inches and Millimeters are not possible options.

Thanks, CCE

[pendean]

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@ceissler9A6GZ wrote:

I understand that many CAD drawings are in measuring units of inches or millimeters.

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No. AutoCAD is unitless: a unit can be anything from micron to a lightyear.

I suggest you ask the DWG file creator which software did they actually used (May not be plain AutoCAD) and which GIS they used: then ask them your question.

OR... share their DWG file here, maybe someone can guess at it.

[ceissler9A6GZ]

I have no idea wher the data came from and it is clearly in "inches".
My question is "how anyone using AutoCAD can assign a GIS coordinate system with the units still in inches"?
In other words, what would that "workflow" be?
Thanks,

[pendean]

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@ceissler9A6GZ wrote:
I have no idea wher the data came from and it is clearly in "inches".
My question is "how anyone using AutoCAD can assign a GIS coordinate system with the units still in inches"?
In other words, what would that "workflow" be?
Thanks,

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Those are all excellent questions to ask the creator of the DWG file. Reach out to them ASAP.

And there is a good chance they have no idea either, like you, they may just have inherited the file.

No one here can dissect a history of a DWG file or tell you what others have done: if you want to share their DWG file here, someone might be interested enough in examining it to help you fix it (if it needs fixing) for your non-Autodesk software.

[Pointdump]

Hi Craig,
"I'm wondering how this happened in AutoCAD in the first place..?"
Likely started the drawing with an "architectural" template. I see it all the time. Easy fix is to use -DWGUNITS and either allow or not allow scaling.
Dave

[ceissler9A6GZ]

It's a "concept" question; not to be taken so literally.
Think of it this way: "If YOU wanted to do this, how would you do it?"

..."this" means assign a GIS coordinate system with units in inches.

[ceissler9A6GZ]

...For instance, the AutoCAD Help doc says this about GIS coordinate systems: "The system uses the setting stored in the INSUNITS system variable as the default linear measurement of a drawing unit. However, when you insert geographic location information, you have the option of specifying a different linear measurement for a drawing unit".

...SO, does this mean an AutoCAD User can assign the DWG a GIS coordinate system (which has to be in degrees, feet, or meters), then change it to be in something else, like inches? I...f so, that explains it and answers my question.

[pendean]

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@ceissler9A6GZ wrote:

It's a "concept" question; not to be taken so literally...

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So you lied mis-typed?

"...I have received a DWG file created in AutoCAD with an assigned GIS coordinate system..."

You should be working with the file creator to resolve the issues, so your hypothetical has already been answered. Three time now 🙂

[ceissler9A6GZ]

Be nice. ...It doesn't matter "who" did it.
I'm asking what "tools or settings or whatever" are used in AutoCAD to assign a GIS coordinate system then change the units to inches. If you're not sure, that's fine -- please allow someone else to answer that question -- which has not been answered as far as I can tell.