Wow, what a great start! Unlike GES DISC OPeNDAP server, I think the PODAAC OPeNDAP server that you’d like to access doesn’t require Earthdata Login credentials. That eliminates a lot of complications.
My suspicion is that your R ncdf4 package is not built with OPeNDAP support. Can you check if your R ndf4 package work with our demo OPeNDAP server [1]? If not, you may want to install ncdf4 with your own netCDF-4 library that enabled OPeNDAP support. Once [1] works with your R ncdf4, I think my posting [2] can help you to redirect URLs properly for NASA credential-enabled OPeNDAP servers. Good luck and thanks for sharing your code on GitHub! [1] https://eosdap.hdfgroup.org:8080/opendap/data/hdf5/grid_1_2d.h5.dmr.html [2] https://hdfeos.org/forums/showthread.php?t=821#4 From: Ben Tupper <btup...@bigelow.org> Sent: Wednesday, April 13, 2022 8:59 PM To: Joe Lee <hyok...@hdfgroup.org> Cc: r-sig-geo@r-project.org Subject: Re: [R-sig-Geo] Earthdata CMR access What I have can search for S3 resources, but I happen to focus on OPeNDAP instead. As far as I can tell, the ncdf4 (and RNetCDF) packages don't provide utilities for establishing credentialed opendap connections. That is handled by sort of a third party or some kind of wrapper. Without credentials I can search, but without credentials I cannot open a connection to the opendap resources the search yields. If I am understanding the error message shown at the bottom of the README (see below), the server is receiving the request but for lack of credentials is refusing access. I'm stumped. https://github.com/BigelowLab/cmr On Wed, Apr 13, 2022 at 2:18 PM Joe Lee <hyok...@hdfgroup.org<mailto:hyok...@hdfgroup.org>> wrote: > > Yes, that's the hard part that I'm referring to. > > Once you pass that step, you may also want to look at another example in > MATLAB [1] > to access PODAAC data on S3 using the temporary token. > > I'd really appreciate your effort if you can share a working R-code project > that can both search with CMR and then access NASA data on S3. > > Regards, > > [1] > https://www.hdfeos.org/zoo/PODAAC/ATM_SURFACE_TEMP_HUM_WIND_PRES_day_mean_ECCO_V4r4_nc_c.m > > > -----Original Message----- > From: Ben Tupper <btup...@bigelow.org<mailto:btup...@bigelow.org>> > Sent: Wednesday, April 13, 2022 1:09 PM > To: Joe Lee <hyok...@hdfgroup.org<mailto:hyok...@hdfgroup.org>> > Cc: r-sig-geo@r-project.org<mailto:r-sig-geo@r-project.org> > Subject: Re: [R-sig-Geo] Earthdata CMR access > > Hi, > > I was planning to use the httr package or the newish httr2 package which > should be able to handle the transactions. Once a resource is tracked down > via search, I plan to use the ncdf4 package to access. > > I can add headers to the http requests, so presumably that can include tokens. > > But I am finding even the simple stuff like using the API to generate a > token, as shown here > https://wiki.earthdata.nasa.gov/display/EL/How+to+Generate+a+User+Token > , to be challenging. Thud! > > Ben > > httr: https://CRAN.R-project.org/package=httr > httr2: https://CRAN.R-project.org/package=httr2 > ncdf4: https://CRAN.R-project.org/package=ncdf4 > > On Wed, Apr 13, 2022 at 1:03 PM Joe Lee > <hyok...@hdfgroup.org<mailto:hyok...@hdfgroup.org>> wrote: > > > > Hi, > > > > I'm also interested in the solution that you're seeking since I've > > written a Python-equivalent CMR+OPeNDAP workflow a very long time ago [1]. > > > > It's both very tricky and difficult nowadays because NASA tries to > > constrain AWS egress cost via Earthdata Login authentication. > > > > Does R provide a cURL-like library + a temporary token-based authentication? > > > > [1] > > https://earthdata.nasa.gov/collaborate/open-data-services-and-software > > /api/opendap/gesdisc-airs-opendap-cmr > > > > > > -----Original Message----- > > From: R-sig-Geo > > <r-sig-geo-boun...@r-project.org<mailto:r-sig-geo-boun...@r-project.org>> > > On Behalf Of Ben > > Tupper > > Sent: Wednesday, April 13, 2022 11:41 AM > > To: r-sig-geo <r-sig-geo@r-project.org<mailto:r-sig-geo@r-project.org>> > > Subject: [R-sig-Geo] Earthdata CMR access > > > > Hello, > > > > I am interested in accessing physical oceanography data from PO.DAAC ( > > https://earthdata.nasa.gov/eosdis/daacs/podaac) from within R using > > opendap. NASA is moving its data offerings to the cloud, and it is > > adopting Common Metadata Repositories ("CMR", > > https://cmr.earthdata.nasa.gov/search/site/docs/search/api.html) for > > searching. CMR searching is in lieu of searching THREDDS catalogs. > > > > I'm finding the on-ramp to using CMR tricker than I had expected given the > > sales pitch behind CMR (or maybe the wheels have come off my car!) I am > > wondering if anyone in this community has waded into using R-based CMR to > > access cloud-based geospatial data, and, if so, might be willing to share > > some insights or provide guidance? > > > > Regards, > > Ben > > > > -- > > Ben Tupper (he/him) > > Bigelow Laboratory for Ocean Science > > East Boothbay, Maine > > http://www.bigelow.org/ > > https://eco.bigelow.org > > > > [[alternative HTML version deleted]] > > > > _______________________________________________ > > R-sig-Geo mailing list > > R-sig-Geo@r-project.org<mailto:R-sig-Geo@r-project.org> > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > > > _______________________________________________ > > R-sig-Geo mailing list > > R-sig-Geo@r-project.org<mailto:R-sig-Geo@r-project.org> > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > > > -- > Ben Tupper (he/him) > Bigelow Laboratory for Ocean Science > East Boothbay, Maine > http://www.bigelow.org/ > https://eco.bigelow.org -- Ben Tupper (he/him) Bigelow Laboratory for Ocean Science East Boothbay, Maine http://www.bigelow.org/ https://eco.bigelow.org -- Ben Tupper Bigelow Laboratory for Ocean Sciences https://www.bigelow.org/ Tick forecast https://eco.bigelow.org/ [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
