Best practice for managing projection/coordinate systems with feature services? Collecting results skew based on technique.

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02-24-2022 09:31 AM
SFM_TravisBott
Occasional Contributor III

Is there advice out there for how to handle projections when collecting data in a feature service? Our workflow involves collecting polygon data from disparate areas, and we've been having field workers append locally-collected data to a feature service so it can be QC'd and pulled down by a data steward. Results seem to differ depending on various techniques, and I do not know how best to standardize it.

Standard display for items on AGOL is WGS 1984. However, if you publish a layer to AGOL it retains the spatial reference it was published in (or at least it says it does). Below is a feature service, accessed in Pro, that seems to have retained the spatial reference of the original feature class.  

SFM_TravisBott_0-1645722605357.png

First question: Should one make sure a feature service stays in the intended output feature class? We will ultimately archive the data in Teale Albers; is it best practice to have the feature class projected as such so as to not skew out put?

Second question: I have noticed changes happen as data is transformed going in/out of feature classes, and I would like to pinpoint the issue. 

For this scenario, the feature service is in WGS 1984. Local parent data is in Teale Albers. Map is in Teale Albers. When appending the data to the feature service it gets skewed. When it gets exported back out to Teale Albers it remains skewed. See below. 

SFM_TravisBott_2-1645723559608.png

However, if the original data is added to the feature service by Copy/Paste, it remains correct, both as projected in the feature service and upon export. 

If data is re-projected to WGS 84 prior to appending, then exported in Teale Albers, the output would be correct. I would like to avoid having field staff re-project their data prior to appending, so want to know how to set up the service properly. 

So: What is the appropriate technique for managing projection differences in our workflow? If we plan to collect locally stored polygons in a feature service, and then export them in a particular projection, should the feature service be in that projection? Is this further complicated if we also want to collect data in the same feature service on a mobile device?

 

 

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