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California CRTN Users-A few questions
I don’t often use the CRTN, BUT working on a couple California projects currently that I will use that RTN. The CRTN official spreadsheet shows coordinates to the monument (which is different than any other RTN I have ever used, but I am sure there must be a good reason). I would assume the broadcast positions are to the ARP since they are different, however either that isn’t clear or I missed the memo.
When I look at the two values, in my mind the broadcast RTN stream actually seems to apply the difference between the monument and ARP in the opposite direction so all those 8.3mm SCIGN mounts appear to have a coordinate 16.6mm different than the published monument Hae.
Maybe I am looking at it all wrong? Can any experienced users of the system confirm that broadcast data stream is actually to the ARP?
Work in the Redlands, CA area also results in first order vertical marks measured with the RTN to be around 0.1 meters lower than NGS published. That may be true, but any thoughts on adjusting vertically to monuments there vs CRTN values + Geoid model would be appreciated.
Starting tomorrow, I will be in Lakeport, CA area and will see how vertical fits in this area, so may have questions again about that.
As a general rule most of my projects no longer get adjusted to local hard monuments as here on the entire west coast it seems there is too much movement both horizontally and vertically to trust even HARN/HPGN monuments any longer, let alone BM’s from 50+ years ago.
SHG
Edit to ask another question, is the baseline length geofenced to some distance like 30 km? I didn’t see anything published re that, BUT 30.5 km currently seems to be a no go. I realize that is a bit long for single baseline, just curious why while I can connect, no fix is forthcoming.
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