I am sticking with a local base as this is the method that I am trying to create a proposal for to introduce more Emlid devices in the field. I will transform the data in QGIS moving forward. The part I am unsure of is entering the NAD83 values into the base and telling it that is what it is using. Is it just the actual coordinate with no scaling involved? I just enter it into Base Mode as I would normally do for a manual point? This is a problem we run into when working with Survey and Engineering design files. The enter scale factors for the State Plane coordinates that we want to get to in the end.
Another question I have been thinking of is how does simply stated āNAD83 (2011)ā relate to local geographic locations? When you get down to the State plane level in the US there are over 100 projections in zones across the US each having their own 0,0 so my 3m,10m XY is not the same as the area 100 miles south of me. I am trying to learn how "NAD83 (2011) can be a common value.
Yes, you can just enter your coordinates in NAD83 into Base Mode and use it. Iām not sure what do you mean under scale factor, but I suppose itās projection parameter. Take a look at this example of projection, there is scale_factor=0.99996.
You donāt need to worry about it when you entering your base position since itās projection parameter related to the certain State Plane CRS, not to geographic NAD83, and it will be automatically applied by RV3 during transformation.
NAD83 has LLH position that is shared for the whole continent. And this position can be projected to the plane using some parameters, that are responsible for the final plane XY coordinates. The same LLH point in NAD83 can be represented with different plane XY coordinates when you use different projections.
Some tips for converting coordinate systems:
- Use the newest versions of WGS84 - WGS84(WGS 84 (G1762)) and NAD83 - NAD83(2011), they have more precise transformations.
- Use 3D versions (itās still LLH) of CRSs to prevent from height coordinate stripping. For NAD83(2011) itās EPSG:6319
- Difference between WGS84 and NAD83 changes in time, so the transformations are time-dependent. For results to be more precise use transformations that include fourth coordinate - epoch when your point was collected
After you set up your base, try to collect some point with known coordinate, eg landmark, to assure that your setup is correct
Thank you. So does this mean that I need to average in the point normally then convert that value to NAD83 and manually enter it back in? Is the ellipsoid height left alone or do I need to convert the to a geoid or orthometric value as well?
Hello @rfreedii!
We do have advanced surveying features like these in our plans. Right now our primary goal is to add coordinate system support to the app. This, along with a full set of Reach settings, needs to be done before we can advance further into cool surveying stuff.
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Hi Andrey,
ReachView 3 supports iOS 13 and higher due to technical reasons. Unfortunately, that means some of the older devices will not be able to access the app.
Iāll admitā¦ Iām giddy with RV3. It has simplified greatly what Iām utilizing the system for. Looking forward to your future features. Iāll be pushing the system to fellow pipeline bending engineers to make their work simpler as well.
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It would be better to use PPP to get a precise position in WGS84, simple averaging even during long time can give you some significant inaccuracy.
For base coordinates use ellipsoidal height. Orthometric height for collected points will be calculated later automatically in accordance to the Vertical Datum you have chosen in the RV3.
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You can also process with OPUS and get a NAD83 position for your base.
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I am just trying to figure out how I can do this in the field. Seems like these options work well if you are using NTRIP, but may not be the way to go for a local base. Maybe if I can take a control point from the plans or CAD that has a State Plane coordinate I can work it backwards to NAD83 LLH before I am in the field, but if I donāt have any pre-documented control I should probably just stick to WGS84 and transform back in the office. The huge benefit to doing it in the field would be the ability to provide State Plane coordinates on the fly or even calculate a position relative to a plan detail, but I guess this leads me back to FieldGenius for now.
Maybe I could do this a different way? What if I set up my base and shot in another base point with my Rover on rtk? If I let the initial base average for 20 or 30 minutes do you think the rtk point would be accurate enough to use as my baseline. Keeping in mind that I can always adjust points in cat after the fact.
If your project is in State Plane and you have some control points on site here is what you can do. Configure base as average single, you will end up with a WGS84 coordinate that should be within a few meters of a true NAD83 position. Configure project as State Plane. Make sure to measure the control point on site, you will use that to shift the whole project in CAD afterwards. Effectively this produces a shift vector that fixes the inaccurate base position. We have plans to introduce such workflow in RV3, but you already know our priorities right now 
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Good stuff, but would an RTK collected point be better? I guess it really doesnāt matter if Iām shifting in CAD, but sometimes it doesnāt matter so much if Iām doing just a quick verification Topo. do anything with CAD as you sort of mentioned is that when I am doing that shift it is done in a way that is almost identical to the localization that we are doing in the software. It really depends on how many control points I have as to how close it is to a software localization.
Love the new RV3. Any thoughts of setting up the ability to have any of the settings that are saved in the app to sync to iCloud and then be available in the app on other devices? Iām thinking this could be useful with the NTRIP profiles.
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They actully have this already. If i understand you correct.
Take a look at the profile at bottom right corner and top first choise in the next screen, its saved on your phone and applies to all Reach unit you use/connect to.
Correct but what Iām thinking is if I want to use a different device than the original one that I set all the profiles up on having the iCloud sync would permit the new device to have access to those already saved profiles.
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Ok, not sure i follow you 100%, but sync setting to someone els for example?
Letās say that originally I use an iPad mini to set up all of the NTRIP profiles. That iPad mini gets broken and for the day I need to use my iPhone. Having the ability to sync the profiles via iCloud would give me the ability to just pick up my iPhone, log into the RS2 and instantly have access to the NTRIP profiles that I already set up.
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Ah got it. Not a function at the moment no.
Was thinking of pointing file explorer app and remote sync each time a file was updated but the profile doesnt seem to be visible in the Reachview app folder.
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