topic Re: Unstable Projection? Data not lining up, why? in Coordinate Reference Systems Questions

Unstable Projection? Data not lining up, why?

JacquelineAlessi — Tue, 26 Mar 2019 12:15:08 GMT

I have several FDS that are set to Nad State Plane South (WKID: 2253) that I want to project to WGS 84 WEb Mercator (WKID: 3857). I have been using the NAD_1983_to_WGS_1984_5 transformation. This was working for a while but now my WGS datasets are drawing about 3 feet off of where the points were. I didn't change any of the parameters in my GP tool. I can run the Projection in catalog, pull the FC into an MXD with Imagery and they are fine, but once I save the map and reopen it the imagery and FC no longer align. The imagery and the FC are the same Coordinate system. Please help!

Re: Unstable Projection? Data not lining up, why?

MatthewDriscoll — Tue, 26 Mar 2019 12:52:47 GMT

Sounds like it might be a meter-feet issue. Check to make sure they are using the same type of units.

Re: Unstable Projection? Data not lining up, why?

JacquelineAlessi — Tue, 26 Mar 2019 12:55:38 GMT

Of Course they dont, State plane is feet and WGS is in meters. But that still doesnt adress the issue. this projection process has worked Since December without issue. NOW, as of yesterday it doesnt work.

Re: Unstable Projection? Data not lining up, why?

MatthewDriscoll — Tue, 26 Mar 2019 13:27:20 GMT

Sorry I meant does the map have the same units as the imagery and FC? I agree this should not matter, trying to narrow it down.

Re: Unstable Projection? Data not lining up, why?

JacquelineAlessi — Tue, 26 Mar 2019 13:29:31 GMT

Yes once projected to WGS 84 they are set to the same units.

Re: Unstable Projection? Data not lining up, why?

MatthewDriscoll — Tue, 26 Mar 2019 13:36:15 GMT

Does the same thing happen if you use WGS_1984_(ITRF00)_To_NAD_1983?

According to this article NAD_1983_To_WGS_1984_5 has an accuracy of 2 meters where WGS_1984_(ITRF00)_To_NAD_1983 is 0.10.

Re: Unstable Projection? Data not lining up, why?

JacquelineAlessi — Tue, 26 Mar 2019 13:45:17 GMT

Yeah it is identical either way.

That was my first ditch effort, also as a side note it was the Transformtion that I argued for in the first place but in my work place the the microsoft developers know more, and we dont get much of a say...

Re: Unstable Projection? Data not lining up, why?

MatthewDriscoll — Tue, 26 Mar 2019 13:55:23 GMT

Sorry, I am out of ideas. Hopefully someone else with better knowledge on this behavior chimes in. Not sure if there is a size limit for uploading here, but if you are able to attached the imagery and feature class to the thread please do so.

Re: Unstable Projection? Data not lining up, why?

JacquelineAlessi — Tue, 26 Mar 2019 13:57:48 GMT

Haha No I cant its all confidential.

Re: Unstable Projection? Data not lining up, why?

MelitaKennedy — Tue, 02 Apr 2019 16:41:03 GMT

Hi Jacqueline,

Is the same transformation set in the map? Are you using ArcGIS Desktop or Pro? Which version?

As I think you know, 3 feet / 1 meter is a classic sign that a transformation isn't being applied for data that's in NAD83 versus WGS84 so it is certainly something to do with a transformation.

Melita

Re: Unstable Projection? Data not lining up, why?

JacquelineAlessi — Tue, 02 Apr 2019 16:54:21 GMT

The Answer is dependant, each of the following represents a new MXD:

1.) When I pull in the result of the Projection to WGS84 and the WGS84 Imagery there is NO transformation set in the data frame because the data frame, the Raster, and the Vector are all in the same Coordinate System, But they don't align.

2.) When I compare the output of the projection in WGS84 to the input NAD83, the transformation IS set and they still don't align.

3.) When I compare the input in NAD83 to the Imagery in WGS84 with the translation set they align perfectly.

10.6.1 ArcMap

Re: Unstable Projection? Data not lining up, why?

JacquelineAlessi — Tue, 02 Apr 2019 16:56:48 GMT

What Im getting at is the output is the only things that does not align. What I need to make clear is that this only happens when I run batch project at the FDS level. If I batch project on FC there is no issue except for with the ones that have advanced capabilities which is to be expected. However I need to maintain my network and topology so where does that leave me, haha