XY Coordinates Don't Match Map

[JacobMurel]

I'm having a problem with mapping my x.y (long, lat) points on ArcGIS Online—I only have access to Online, not Pro or Desktop. I've checked my long/lat points against other sources (e.g. Google Earth) and they appear in the correct spot there, but when I upload them to my Online map (as a .csv file), they appear slightly away from where the point is supposed to be. Are there any thoughts on how to fix this?

N.b. I've checked past questions/discussions that seem to encounter this same issue, but none of the solutions work:

1) Here they recommend switching base layer to geographic-world-wgs1984, which I did (among other base layers) and still encounter the same problem.

Lat Long into ArcMap Problem 

2) Here the responder recommends changing data frame's coordinate system, but I can't figure out how to do that on ArcGIS Online—Google was no help here.

XY coordinates and data frame correct but points are displayed in the wrong location. 

Any advice is appreciated!

[Pål_Herman_Sund]

Changing coordinate system in AGOL is done by changing the basemap (i.e the basemap set the reference system). 

"Slightly away" .. could it be:

1. you miss the decimals in the import
2. there is a datum problem (i.e normally in the range of 50 - 400 meter off) but could be more and also less

If You gave one example of Your XY's that could be helpful. 

[JacobMurel]

Thank you for the response!

I checked the input values after reading your comment, and it seems the values were not precise enough. For example, I changed the point

-157.65, 21.3

to

-157.654198, 21.297908

and the second, newer value input is closer to what I want. So it seems I needed to be more precise with my inputs.

The point is still a little off however. In the attached picture, the more precise input value appears as the peach dot. But in Google Maps (GM), the same coordinate value appears where the red dot is. Using AGOL's measurement tool, the longitude value for the red dot in AGOL is -157.654135. Do you think this difference is simply that the basemap may be a little off from GM? Admittedly, now that I've fixed the input values, the difference is incredibly minor. But I was curious if this is problem with transferring GM long/lat measurement into AGOL, or simply a matter of me needing to adjust the dot manually given it is already so close to what I wanted, or something else.

[Pål_Herman_Sund]

Hi. Given the maps are orto's from satelites (?) there are a number of error-sources here (trajectories for the SV's, DTM for the rectification, sensors etc etc) which might explain the differences. There might be something with reference system as well - "WGS84" vs ITRF20xx and "some epoch". 

Sorry - have no better answer.  

[JacobMurel]

No worries! I appreciate the helpful responses. For the purpose of my project, the incredibly minor offsetting will likely not prove a huge deal anyway. I was just curious if it could be fixed easily.