Correct GEOID selection in SWMaps with RTK Facet

Good afternoon,

I purchased an RTK Facet and it is amazing. I’ve located a few survey monuments in my area and can confirm that accuracy is excellent. It is well within the 14 (10mm) claimed accuracy in horizontal and vertical. I confirmed the latest ellipsoidal monument height to within 7mm accuracy and probably have some error caused by my lack of being as accurate as possible with antenna height above monument.

I live in Oregon and have been using the ORGN network of RTK corrections. I receive the data just fine and can get RTK fix in just a few seconds in most areas. Unfortunately I’m having issues getting the correct GEOID in SWMaps and could use an assist. According to the ORGN documentation they are using 1984(2011) Epoch 2010 and require 2012A for the GEOID. I’m just familiar enough with this to cause trouble. Does SWMaps use the .gtx file format for GEOIDs? Do you happen to have a GEOID file you’d recommend for the area (I’ve been using NGS .gtx files but cannot get orthographic elevation to show up in SWMaps and don’t believe I’m actually getting corrections???). Sorry for the long poorly worded questions thank you for any help you can offer.

Welcome Daniel!

Thanks for the positive feedback (leave the product a review perhaps? :)).

I’m just familiar enough with this to cause trouble.

Me too. I hope Tony or someone else with more knowledge about Geoids to chime in.

It is possible to change the Datum for the ZED-F9x inside the Facet (https://github.com/sparkfun/SparkFun_u- … issues/151) but I’m not sure if this will alleviate your problem.

Thank you for the feedback Sparky,

I’ll send a message to the SWMaps folks and ask the ORGN network administrators if they have solutions as well. If I find anything I’ll post it back here so people know how to make the correct adjustments to get orthometric heights with SWMaps + RTK Facet + free correction service like ORGN / CORs. Overall the unit is awesome and it wouldn’t be too terrible if I just have to take data and run through external correction software to get orthometric heights for the points, but it sure would be nice to see the data on SWMaps in real time.

Working with the SWMaps folks sounds like the right approach. Looking forward to hearing what happens, this would be very useful.