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SurvNet beginner help
Looking to start using this since we combine GPS and TS work. One question: Do I have to keep HI and HR to be able to mix GPS and TS data in LSA programs? The majority of our work is rural boundary and we rarely carry elevations. Looking at tutorials, to add GPS data I must use 3d? I really just want to add GPS coordinates as control and adjust TS traverse into them. Thanks in advance for anyone who can shed some light on this!
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7 Replies
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It definitely helps. Although I guess you could enter everything in as 5.0′ with a target and instrument height error of 1′. Then you’d be in the ballpark to get a good 2D adjustment. You vertical component would look nasty, because it is, but doesn’t really matter. That is how it would work in TBC, anyway – I think SurvNET may have a 2D only option from the get-go. I carry true heights on everything, because I do almost zero boundary-only work and the last thing I need is someone getting ahold of a control point with an “almost correct” elevation. I am almost fanatical about not keeping data that looks good, but isn’t.
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Yes.
GPS is a three dimension surveying system, the measurements are by their nature three dimensional. Therefore heights are needed to simultaneously adjust GPS vectors with Total Station measurements.
StarNet can do a 2D adjustment but it requires 3D when using GPS vectors.
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I have just always carried elevations with my traverses whether I need to or not. It has long since stopped being a big deal. Yes, you need to if you are going to simultaneously adjust GPS and traverse data.
You can just hold your GPS determined points in your adjustment. Give them a standard error. But I recommend just getting into the habit of 3d traversing.
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Dave Karoly has it correct. Refer to the “Two Mathematical Models, 2D/1D and 3D” discussion in the SurvNET Introduction for additional information.
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Thanks all. I have been using the mini prism on a bob string and been leaving the rod in the truck. In rough terrain, it??s one less thing to carry while cutting line. In order to do this, it looks like I might have to use the rod again. I may try setting HI and HR at 5?? and see how that works too.
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If you want to hold your gps points as control just input them into your raw file as control points. In survnet settings, set the control standard errors to 0,0,0,0. The raw file will be least square adjusted to the control points. You don’t need elevations to do this.
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I just heard that the shutdown will end very soon – for 3 weeks, anyway – so you could get grid values from Opus and enter those in your rw5 as control points, show a small standard error for them and then you don’t need 3D. The most common reason I’ve found for the program not to converge is 2 different points with the same number, or conflicting measurements for the same line, i.e wrong Sta./BS or similar.
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