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The existing AHPS netCDF files available here: https://water.weather.gov/precip/p_download_new/

do not include a projection...instead they're described as being in an HRAP coordinate system. Further the data is offseted via hrap_xor/hrap_yor. If you open the file in QGIS you need to provide a projection.

What is the proj4 for AHPS netCDF files to be able to display properly in QGIS?

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By opening the newly formatted files available: http://preview-water.weather.gov/precip/downloads/2017/

and tweaking the projection those include I was able to create a custom projection that seems to more or less get the two files to overlay:

+proj=stere +lat_0=90 +lat_ts=60 +lon_0=-105 +k=1 +x_0=1842796.9875 +y_0=3705005.475 +a=6371200 +b=6371200 +to_meter=4762.5 +no_defs

Hopefully this can help someone and we can get a truly correct one!

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  • wouldn't it be nice to have acronyms "explained" for noobs (like me) ? ... sure it is easy to google them .... but ... – Snaileater Jun 8 '17 at 18:23
  • welcome to world of corporate/government :) – amohr Jun 8 '17 at 19:11

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