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Entered wrong base-coordinates, how to correct


(Christian Grüner) #1

I made a typo when entering my base coordinates today, and so my survey is offset.
Any idea how fix in QGIS, or is there a better solution?
I have the correct base coordinates, and the wrong ones, so should be easy to calculate the offset (can that also be done i QGIS?).


#2

yup. whats your final coordinate system?


#3

Here is a screenshot from a different user having the same problem
image

What i did was to:
1.import points to qgis
2.Change projection and apply shift variable


(Tracy Love) #4

i did the same thing the other day
qgis , go to the toolbox, /vector geometry/translate
(there is also /vector geometry/project points/ )

since they seem to use distances i may have run the two points (the point you put in and the point you wanted to put in) through Inverse first…

https://www.ngs.noaa.gov/cgi-bin/Inv_Fwd/inverse2.prl


(Tobias Dahms) #5

Why don’t you post process? Are you having access to the base observations? I could run the files through my script if you like.


(Christian Grüner) #6

Would love to, but my base unit was collection static point data over night, and now won’t turn on, so can’t get to the base-log currently :S


(Christian Grüner) #7

ETRS89, which is what I have entered for the base coordinate.


(Christian Grüner) #8

Where is the toolbox?

I can find this: https://docs.qgis.org/testing/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#translate

but not where it is found?


(Tracy Love) #9

i assumed before that your data is already RTK corrected, if so then you just need to shift it, if not then you need to post process.

QGIS: View/panels/processing tools box/
then search for : translate


(Tobias Dahms) #10

Did you have any success? If you provide the UBX files, the base position and the csv file of the survey I can post process the points for you.


(Christian Grüner) #11

Post-processing isn’t a problem for me, just wanted to learn how to correct in QGIS, but thanks for the kind offer!


(Christian Grüner) #12

In the View -> Panels, I don’t have a such item. I’m on QGIS 3.4.4. Is it a plugin or something like that?


(Hunter) #13

Say several months after the fact I need to see what my base coordinate was, where do I find that? I see I have my RTCM3 message from base but do I need to convert it to another format so I can open in Notepad or similar?

Typical Scenario: I collect average coordinates for base with no correction input and save to survey and then operate in RTK. After fact I PPK my base coordinate. My RTK survey went great, all points had fixes. Just need to shift.


(Tracy Love) #14

oh sorry yes it is a plugin, called “Processing”
i always have it loaded so i forgot its not a core thing


(Christian Grüner) #17

Got it! Needed to activate it first.


(Hunter) #18

Sorry misread @tracy.love post :wink: I’m on QGIS 3.2.1 and in all my other versions of QGIS have never had to load the processing toolbox, strange.


(Tracy Love) #19

yeah i think that is what i need to learn to do when i can not ntrip it or opus it to begin with. but then all you can do is PPK with IGS product right? or do you go get data from CORS?

i have used http://apps.gdgps.net/
and i have used the Canadian PPP service https://webapp.geod.nrcan.gc.ca/geod/tools-outils/ppp.php?locale=en

but the accuracy wasnt fantastic even with a l1/l2


(Hunter) #20

I just PPK my base against a CORS site. I’m playing with a project right now that I have to do just this on but am forgetting where to find or how to extract the original uncorrected base coordinate. It’s buried in a header somewhere…


(Tracy Love) #21

OH, damn, well i hope you find it and i hope you tell me cause that sounds like a common situation i would find myself.


(Christian Grüner) #22

The link to the inverse calculator you gave above, only gives a direction and slope distance, but the Translate-tool need XY offset. Do you know other tools (online or in QGIS) that can provide this from 2 coordinates?