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TBC Noob Question
So I’ve expired my 30 day trial of TBC, but can still bring new data in and manipulate it. Just can’t do almost anything else. Here’s the question:
I set the dxf’s and points up in CAD as SPC in my zone. Shooting with an S6 robot, TSC3 with Access 2017, I set the datum info to my state plane and linked the files in the DC. I shoot stuff, come back, export field points, bring it into CAD (C3D), which is also set at my SPC zone. Everything comes in perfectly.
I start a new project in TBC with the same coordinate system, geoid, etc, import the boundary dxf, site features dxf, baseline points and boundary corner points. All come in great. When I import the field shots, though – the same csv exported and used to bring into CAD – they’re all showing up about 80′-90′ south of their actual locations. Looks like the whole field shot data is skewed slightly as well.
The grid coordinates showing in TBC for any of those points seem to have been transformed with a slight rotation as well. Any ideas? Also, why would the corners and baseline come in perfectly but the field shots not?
Thanks,
Dave
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5 Replies
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Weird. I guess it has to do with how I imported them to TBC; I may have imported them as PNEZD (control) but when I import as PNEZD (unknown) they come in correctly.
Is there an easy explanation for that?
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That wasn’t it. Now I don’t know why they’re coming in right…. and couldn’t see how to delete that last bit of info…
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I guess it has to do with how I imported them to TBC; I may have imported them as PNEZD (control) but when I import as PNEZD (unknown) they come in correctly.
Is there an easy explanation for that?
Yep. TBC’s computation engine has a hierarchy. If the user brings in additional data to a project, with point names/numbers that are already existing in the project, their class (unknown/survey/control) is taken into account when recomputing the project. Workflow and import order matters.
Generally, best practice is to bring in raw data (JXL or JOB), then import master control values as control class. If there are two control-class coordinates for the same point in the project, the most recently imported trumps the older one.
Global is senior to grid, which is senior to local. Coordinates of survey-quality or higher override observations, which are by definition survey-quality.
There’s an old but excellent Power Hour that discusses the computation engine and how it works. Unlike CAD programs, TBC deals with local/global/projected data and raw observations. The bottom line is that there is a ton of freedom for setup, gathering observations, and processing, but whenever there is conflicting data in the project, TBC has to make a decision about prioritization when computing the network. It’s up to the user to decide how best to proceed.
“…people will come to love their oppression, to adore the technologies that undo their capacities to think.” -Neil Postman
youtube.com
TBC Power Hour: Integrating RTK, Total Station, Level and User Entered Data
This webinar was recorded on March 30th, 2016 at 8:00AM MDT. This topic covers:Efficient integration of multiple data sourcesComputation rules and calculatio...
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What are your units. In both dc tbc and cad. Here its around 25 ft. That could be a issue. But as rover stated. Csv is a points file. Tbc can help you have smart traceable data. Bring in the job or jxl. At anytime you can see properties of that point and know which jxl raw file it came from and much more.
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It’ll help to not export points from Access just to import into TBC. Import your JOB file into TBC and once you do that and need to do more field work – start a new JOB file and link your old file to it
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