[RS-ecology] Informal conventions for projections?

[Thompson, Kathleen Marie]

Greetings,

I would appreciate any ideas or resources on how to critically assess assigning projections to data sets when ambiguous or missing metadata make it difficult to identify a "correct" projection. It seems projections that are incorrect, but functionally useful, are regularly assigned by informal convention.

I am working with National Water Information System station locations (USGS). The lat/long coordinates reference NAD83 datum. Where altitude is available, it references NGVD29, NAVD88, or COE1912 datum. However, no initial projection is specified. USGS representatives tell me there has never been a formal mapping between USGS geodetic datums and EPSG. Individuals have made cases suggesting EPSG 4269 and EPSG 7406 should be reasonable, but these seem to be informal usages and/or conventions. After trying both, they seem to produce equivalent maps.

I am working on a corridor that runs between the northern and southern borders of the US. I would expect that distortions are not negligible at that scale, but perhaps I'm wrong?

You can find code and a subset of data here<https://drive.google.com/drive/folders/1WWpAFTo_9mUKKPR8WB7hpWyAfPtQDVtP?usp=sharing>.

Thanks,
Kate Thompson



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