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DOI-USGS / nhdplusTools

See official repository at: https://code.usgs.gov/water/nhdplusTools
https://doi-usgs.github.io/nhdplusTools/
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Getting NHDPlusEROMMA table from NHDPlus HR #218

Closed mariepastora closed 2 years ago

mariepastora commented 2 years ago

Hello,

First of all thank you so much for all your work on this package -- it's wonderful. I'm a beginner R user, and I'm trying to get information regarding flow estimates for each flowline in WBD-HU8 1402 -- my end goal is to map the thickness of the line to its flow estimate. I've successfully downloaded the data I'm interested in with download_nhdplushr(). I'm just quite confused as to how to load it in R from now on, since get_nhdplushr() doesn't seem to take as an argument the table I'm looking for (NHDPlusEROMMA, variable QEMA). When I load the NHDFlowline layer, it doesn't have that QEMA variable.

Is it possible to do this? So sorry if it's in the documentation and I wasn't able to find it. Thanks so much!

dblodgett-usgs commented 2 years ago

Hi there -- you'll have to load the table you want straight from the geodatabase. The get_nhdplushr() function is more or less a convenience that joins the VAAs to the flowlines and loads up some of the commonly used tables. I didn't add the EROM table to that function. sf::read_sf("./path/to/data", "NHDPlusEROMMA") should be what you are looking for?

mariepastora commented 2 years ago

Thanks so much for this -- got it. I'll try to wrangle that in. Out of curiosity before I close the issue, I'm wondering if you know of any way to get historical data for the EROM table? I think I saw this was an average of flows over multiple years, is it possible to get those numbers per flow line for a given year, or do I have to resort to gauge measurements for this? Thanks a lot!

dblodgett-usgs commented 2 years ago

I'm glad this worked out. I am not sure about historical EROM. You'll have to do a little digging.

mariepastora commented 2 years ago

Will do -- thank you for being so responsive!