Geographic Projection In AutoCAD

Hello all, I am new to AutoCAD but have backround in GIS-MapInfo. I
have a bunch of AutoCAD drawings (a local fiber network) that I need
to convert to GIS format, and that part I know how to do. My problem
is that I am trying to determine a co-ordinate system the CAD files
were done in. I dont know how to accomplish this. I have AC-2008,
and I tried looking in, "View-Render-Light-Geographic Location" I
cant seem to find any other place where I can view the existing, if
any, settings.

Thanks in advance for answering My questions

thanks much

Steven

 

Acad dresses up generic Cartesian coordinates to look like other units. The
drawing's author sets this up when they start a drawing, but it can also
subsequently be changed by anyone, creating all sorts of havoc, since a unit
is a unit. A 'unit' van be an inch, a foot, millimeter, meter, mile, etc.,
so if you change them without scaling the model up or down, you've just
changed the real-world size of everything in it.

Unless someone keyed their coordinate system to some other 'real world'
location and orientation, I'm afraid you will have to devise a way to do so.

 

How 'local' are the networks? Buildings, city blocks or larger regions?
Maybe start by looking for an object in the drawings which has a known
dimension in the real world and do a 'dist' on it? Might be difficult with
fibre optics ... One of my sons did fibre-optic drafting work using ACAD
for Telstra in Oz - I'll ask if there are any conventions.

 

Wouldn't be surprised if they weren't to linear scale.