Hey All. I am sure this has come up somewhere but I didn’t find it through search. I was at a site shooting with the network and shot in a local benchmark to note the adjustment I would need to make to my points afterwards and noticed the antenna height that shows up in the point detail is showing 7.001ft when my pole height was actually 6.562ft. Any ideas? Should I adjust the point for that discrepancy and then adjust to the benchmark?
Nevermind. It is set correctly in point collection but I forgot about the 134mm offset which matches perfectly. Bad part is it points out the issue that the ground looped benchmark is 1.042ft higher than what the network shows. Usually I am +/- 0.20ft so now I am left wondering.
Figure it out. Obviously what was on the plan sheet for that benchmark was a typo. I checked two other points that happened to have elevations in the CAD and figured out that the BM had transposed numbers. It said 996.58 and accounting the other points would have been 995.68. Ugh. Now I am 0.295ft lower and have to file an RFI because that was the only official BM they gave us.
Out of curiosity, what is that ?
Request for Information. It’s just an official document that we have to submit when information is lacking or appears to be wrong in order to get the “A-OK” from the designer. Mostly because there is usually a cost impact if anything changes. Like in this instance if the benchmark ends up being bad and they failed to provide an alternate source and that delayed the project for a week then we would back-charge for my time and claim missed days on the contracted duration.
Hi Michael,
Seems like you’re still under the spell of this forum - creating a thread just to figure the question out yourself 
Having an incorrect benchmark coordinate for the reference is indeed disconcerting at best, I get you. Hard to catch where the issue is. Still, I’m glad you’ve solved it!
Just a quick comment about the ReachView 3. It really can add the distance between the receiver’s bottom to the antenna automatically to the pole height. You don’t have to think about it with RS2 or RS+.
5 Likes
… and I will keep doing it. I like to ask the simple questions to get going because they might be helpful to others. I think walking through that process helps show my troubleshooting process as well. I’m pretty good at figuring things out but sometimes you can get totally stumped.
Just to give an update once I got the control points nailed down and did a DTM of the drone data on surfaces that were reliable I was within +/- 0.05ft of the previous topo from the original Surveyors. Pretty amazing considering I was flying RTK with no GCP’s. I had one point that I did a vertical adjustment with and three checkpoints that were also within that range. The other exciting thing is that because this was a design build we only had CAD of a future roadway that we needed to design the building pad according to and the points on line that I found from those Surveyors were easily within 0.10 ft horizontally on the line that I had!
4 Likes
Michael, sure thing! Your threads do help a lot all the users here 
The results are great! Looks like the original Surveyors used RS2 as well 
2 Likes
I’m pretty sure the previous Surveyors used Trimble but you could be right. They definitely used the RTK network though. The downfall is that either they or the Engineer used a scale factor. I understand the reason for a scale factor but this data isn’t going to anything that requires a scale factor so why can’t everyone just shoot off the network?
1 Like
That’s a good question! The answer will be forever a mystery, I imagine
This topic was automatically closed 100 days after the last reply. New replies are no longer allowed.