Setting up a survey job in NAD83(HARN)
I use Trimble gear, specifically a TSC5 and R12 and would like to know how to properly set up a job in the data collector to use a state plane NAD83(HARN) coordinate system. A lot of the monuments where our survey jobs are, are in 83(HARN). We always set a base for our jobs and don't use the VRS network. We create our jobs using Trimble Sync Manager on a computer, and it does have the option in there to select a NAD83(HARN) coordinate system, but the couple of times I did that, when we set up the base and went to Trimble Access on the data collector, we were getting errors saying missing coordinate system or something similar. So we switched the coordinate system in the properties of the job to 83(11) and it was fine.
I am told that every job should be set up in NAD83(11), then we must do a site calibration when on site with multiple monuments. Is this correct? Is there not a file or something that I'm missing that I can load into Trimble Access to use NAD83(HARN) and just set the job up in HARN?
Am I missing something? If you are working on jobs that have monuments with known values in any particular coordinate system, why not just do a site calibration and call it a day if the residuals are good?
You have old monuments presumably surveyed in NAD83(HARN). The issue with that is what HARN?
HARN 83(86), 83(93), 83(2007). HARN simply means High Accuracy Reference Network. They are a set of monuments occupied early on during GPS and available for use today.
There is one in my town, one 30 miles south in the next town, one 65 miles east, and I'm not sure how far the north and west ones are. They will show a new 83(2011) value if you print out the database and a number of superseded values for different years. Which year would be mildly interesting, but I would hold the control monuments, set your DC for the projection (whatever that is and check other monuments). If they don't check, there is a problem. It should be simple to figure out if there is some scaling factor involved and resolve that. But if you set the DC to 2011 it won't matter. The monuments are the basis. The DC doesn't know unless you're tying into RTX or some VRS. The calculations are the same, one is just a newer number.
That being said, you have to have the metadata, what coordinate and LAT, Long was surveyed for the points.
If you have that:
DON"T CALIBRATE!!!
There's no reason to do violence to the coordinate system.
Also, you can collect static on the base point and later OPUS or CORS the file and see how close your monuments are to the latest and greatest numbers,,,,,,,,,,which will change (probably significantly) in a few months.
Or in 2031 which is what I'm hearing.
which will change (probably significantly) in a few months...
Yes, LSAW will be hosting a seminar on this subject next month https://www.lsaw.org/workshops.html-be there or be square!
Dougie
Ya gotta get on META DATA as we all move forward. The epoch or realization of any datum changes and MTA DATA helps us all trace it if we understand and document correctly. HARN as stated above High Accuracy Network. The MTA DATA will be slightly different in every state. As the observations and readjustments were done at different times so that realization of the NAD 83 DATUM is or was in constant change. A man once said that worked and retired from NGS had it stated very well. DATUMS Change often coordinates seldom. Something along those lines. Any way depending on where you are the coordinates of the projection have not really changed that much as the realization of NAD 83 in which it’s first time being documented.
As we approach a new DATUM and a a completely different type of datum along with a new coordinate system from a projection that will be more dynamic than any thing we have seen historically we as Surveyors must document more and better than ever before as it will be a must in order to accurately account for positions we observe. Time dates are of the utmost importance when stating this. Yes a boundary is all relative and we do not need to have a Datm or whatever to do one. Yet if we use this and set a coordinate at a point as being required by more municipalities then we should state the correct meta dat to aid in precisely and accurately laying out the trail to be followed. Can a boundary be done without coordinates absolutely. That accuracy is based on a whole different level knowledge. But we are required in some places to place on the projection or datum. Either we do it correctly or not.
Sonic,
Whatever you do, do not bastardize the existing control by applying a site calibration.
As others have said, NAD83(HARN) is just a realization (adjustment if you will) of NAD83 datum. The HARN adjustments were done regionally resulting in multiple flavors of the realization. As our understanding and modeling of the shape of the earth has improved (along with equipment improvements and crustal motion), so have the realizations. The result is a slight drift in geodetic coordinates. For smaller areas the relationship between grid coordinate is unchanged between different realizations. Unless Trimble is applying a rubber sheet transformation between the realizations then it is all a game of Meta Data labeling on their part.
On a side note, why can't you add your 83(HARN) coordinate systems to Access. Trimble used to have a couple of nice routines for this.
Thanks John, I appreciate the feedback. The survey department I work at recently upgraded from TSC3 to TSC5 data collectors, and we are now using Trimble Sync Manager and Trimble Access which is all on the cloud. So setting up jobs is a bit more tedious than how we used to do it on the TSC3's and we are still getting used to it. I can set the job up in Sync Manager in NAD83(HARN), but the one or two times I tried this I don't think it transferred to the data collector in Access correctly or something, but I didn't have time to dig too deep into it.
Now looking at Trimble Access, the only way I can set up the properties of the job to include NAD83(HARN) is to set the datum grid to NAD83(HARN) but the local datum has to be in 83(11), which doesn't make too much sense to me. See attached picture.
