Distinguished Contributor
Posts: 119
Registered: ‎05-04-2006
Message 1 of 5 (949 Views)

# combined scale factor

949 Views, 4 Replies
06-08-2009 11:51 AM
Where do I enter the combined scale factor so that when I list my points, the grid coordinates are displayed? Also, will the latitude and longitude reference the ground or grid coordinates?
Distinguished Contributor
Posts: 119
Registered: ‎05-04-2006
Message 2 of 5 (949 Views)

# Re: combined scale factor

To answer my own question, I found that if I put the combined scale factor in the label that that would calculate the coordinate times the scale factor. If I use a spread sheet and multiply the coordinates by the same scale factor, I get a slightly different answer. Does LDT take into account the curvature of the earth? This is a very small site and I wouldn't think that would make much of a difference. Also I see that the Latitude and longitude are calculated from the ground and not the grid coordinates. Guess I better stick with Corpscon.
Distinguished Contributor
Posts: 119
Registered: ‎05-04-2006
Message 3 of 5 (949 Views)

# Re: combined scale factor

Sorry to bother all of you again but I brought the dwg into Civil 3D 2010 and got the grid coordinates and Lat and Lon exactly what I am looking for. The answers matched the Corpscon and Trimble calcs. Feel much better now.
Active Member
Posts: 7
Registered: ‎03-30-2006
Message 4 of 5 (949 Views)

# Re: combined scale factor

You will want to be careful with the scale factors listed by the geodetic labeling process in LDD, I just checked the scale factor listed in AutoCAD vs what was listed in Corpscon which checked between the two but is not the combined scale factor, it is just the grid scale factor. When I list the combined scale factor in Trimble TGO, under view, point labels, combined scale factor. & the combined scale factor listed in calculating from TDS Survey Pro on the TSC2 data collector they check against each other as the combined scale factor. So if you are looking at getting true ground distances from your grid coordinates than you will want to scale the grid distances up by the (1 / combined scale factor) to scale up to ground distances. Hope this is of some help.
Distinguished Contributor
Posts: 119
Registered: ‎05-04-2006
Message 5 of 5 (949 Views)

# Re: combined scale factor

Thanks Pete, I appreciate the reply. I have the Trimble TGO so I'll use that next time.

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