Recently, I’ve seen instances where certain points would not be imported in a FBK file. Some users were getting an error message saying the angle was out of range, others probably were but weren’t reporting that. They just started looking for specific points and noticed that they weren’t in the drawing. Examination of the FBK file showed that the point did exist, so what was the problem? Why was it being overlooked in the import process?
Careful examination of the FBK file led me to notice some strange observational data – the horizontal angle for the observation was listed as 89°59’60”. Anyone see anything wrong with this angle? The 60 seconds in the angle pops out really fast – why yes, that is an invalid angle. So what could be causing it?
The common thread in all of these instances was that the data came from a data collector running TDS software. Once I received the raw data for the job, I noticed that the particular entry for that observation was more along the lines of 89°59’59.6” With today’s more precise equipment, it’s no surprise to see a total station recording angles to the nearest tenth of a second (let a gentle breeze blow and you’ll see that number dance all over the place, but that’s beside the point.) However, the conversion software was erroneously rounding that angle up, but not performing the rest of the angle conversion.
In my testing, I converted the RAW file to a FBK without the rounding error using TDS Survey Link, which ships with Land Desktop and Civil 3D. A quick query back to the original case mentioned that the user was converting using TDS Foresight DXM, a transfer/drafting program that many TDS users have in their office. To rule out the possibility of Foresight DXM being the issue, I downloaded the trial version of the software and converted away – and experienced no issues.
After scratching my head for a few minutes, I decided to contact the great team that works in Corvallis, Oregon on the TDS tech support team. I talked with Ken, and he told me that this was a known issue with one of the DLL files in Foresight DXM. That same DLL had been shared in Survey Link, but the latest version does not exhibit this behavior. I checked versioning with him, and found that the last released build of TDS Survey Link was version 7.5.5, released on January 30th, 2003. This also happens to be the version that ships with Civil 3D, so we’re all up to date.
So my suggestion is as follows: if you are a TDS user converting RAW data to FBK files, use the packaged TDS Survey Link program in your Civil 3D installation. You can find it by selecting Survey>Survey Data Collection Link… Ken was unsure which versions of Foresight DXM might be affected, so he agreed with me that the best workaround was using Survey Link. And if you do find yourself with a funky FBK that has these odd angles, open the file in Notepad and perform a search of 60 to find any possible offending observations.
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