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> Hi Dom, > > re: > > Thanks for the guide, the precipitable water, when displayed as described, > > looks great. I've been trying look at the various settings as I've gone > > along to pick up a few hints and tips. > > > Do you know off hand where this data comes from? > > The data is from the Global Forecast System (GFS) model. The display I > outlined used the 0.5 degree (55 km) resolution. > > re: > > It would be great to get precipitable water with a longer time frame. > > One can get LOTS of this data at the U.S. National Climactic Data Center > (NCDC). The process is straightforward: register an email address > and then select the type of data desired, parameters in that data (subset > of the full set of parameters that are possible), and times. The files > will be put on disk for you to FTP. > > re: > > I've also been busy trying to find and visualise various models and couple > > of issues/questions have popped up. > > > > There are four models I'm keen to try and display at the moment: > > > > 1) The Antarctic current model generated by Paul Holland at the British > > Antarctic Survey, that I mentioned before > > 2) The Antarctic atmospheric model (AMPS) produced by Jordan Powers at UCAR > > 3) Global dust output produced by Natalie Mahowald at Cornell > > 4) Global current model ECCO2 generated at JPL NASA > > OK. > > re: > > 1) I'm still waiting to find out from Paul what the original output was. He > > did say that the 10 GB file didn't include grid points and sent through > > another file which he uses to map the data out (grid file). Below are the > > details for our FTP site, Paul's files are saved into the 'Holland' folder. > > As you mentioned, downloading a 10 GB file probably isn't the best, the grid > > file is about 1 GB. > > This is easily doable. > > re: > > It maybe that I just need to link the two files - they're both .nc? > > This should be possible using the "aggregate by time" feature. > > re: > > To upload/download files externally: ftp://Earthfromspace5575:address@hidden > > > > FTP client details: > > > > username: xxxx > > password: xxxx > > URL: ftp.endemoluk.com > > Thanks. > > re: > > 2) Jordan has uploaded a bit of the AMPS output for me to look at, it's only > > a portion (1.7 GB) of the total output that we'd be interested in and came > > as a .tar.gz file. Jordan has since taken the file off of his server, but > > it's in the Powers folder of our FTP if you fancy taking a look. > > > > After unzipping I end up with a list of .nc files for hourly time points > > which seem to load up fine. I was thinking of using isosurfaces set to a > > particular wind speed to highlight the polar jet, I think I've seen > > something similar done by one of the visualisation teams at UCAR. How do I > > load multiple time points into IDV and tell IDV to put them into the same > > timeline? > > The current output of AMPS and 4 days previous is made available online on > our motherlode.ucar.edu demonstration server: > > motherlode.ucar.edu > > RAMADDA Data Repository > http://motherlode.ucar.edu/repository > > Projects > http://motherlode.ucar.edu/repository/entry/show/RAMADDA/Projects?entryid=1c0cb8d1-5177-4028-b685-577cbbf44ef6 > > Antarctic IDD > http://motherlode.ucar.edu/repository/entry/show/RAMADDA/Projects/Antarctic+IDD?entryid=2c55cb2c-82ff-4c1f-8215-1fdb14ae46da > > The model output is available in GRIB in the folders under AMPS Model Output. > This is available directly in the IDV through the Catalogs selection. > > re: > > 3) Natalie has shared her global dust model output. These are relatively > > small files and can be found here: > > > > http://www.geo.cornell.edu/eas/PeoplePlaces/Faculty/mahowald/fordominic/ > > > > I'm particularly interested in DSTQ.00.nc as this contains data in 3 > > dimensions. What I'd like to do is try and select an isosurface that shows > > how the dust rises and travels across the Atlantic (and other locations). > > The problem is that IDV doesn't seem to identify the Z component and gives > > it a null value. I can display each level individually though. > > We will take a look to see what my be missing from the file(s). > The dataset is 280m in size, I will check it out next week from office. > re: > > Also, the dust range is fairly logarithmic, at the lower levels there are > > very small differences in dust concentration (e-12 to e-11) and when the > > default colour bar is used (in this range) you see nice eddies in the dust > > movement. However at higher levels the dust is in the e-8 range and the > > standard linear colour bar doesn't resolve the fine detail in the very low > > concentrations. > > Yuan will need to comment on this. > The color table is linear, however, we should be able to pick up some details in the dataset through applying the certain scaling factor. > re: > > Failing being able to visualise this in 3D I was thinking of displaying each > > level individually, which our CGI team can stack and fill in the gaps. > > Ideally the colour scale would be consistent through each level and be able > > to show the fine detail throughout the e-12 to e-4 range. > > > > I'm guessing if isosurfaces are possible it's going to be limited to the > > higher dust concentrations and the detail would be lost anyway. Also, it > > might be a bit of a cheat showing values on the logarithmic scale, the finer > > stuff you wouldn't see! > > > > On a side note, how does IDV decide on the default values for the colour > > scale? > > A default is assigned for each dataset, and this can be changed by the user. > I will let Yuan lead you through this. > Basically, there is a default xml table to assign the default color table and range. You can always make the change to this table, or select different table after the image being created. > re: > > And is there a way of browsing the values or a summary of the values > > in the data - like maximum and minimum values, mean distribution? > > Again, this is a question for Yuan. > The IDV do have a formula to find the max and min in the grid dataset, but only in the time dimension if I remember correctly. Yuan > re: > > 4) The ECCO2 directory can be found here: > > http://ecco2.jpl.nasa.gov/data1/cube/cube92/ > > > > I need to double check with the PI which are the most relevant data sets to > > work with (is THETA commonly temperature?). In any case the data are > > presented in individual time steps (like Jordan's AMPS output) and are .data > > files. Are these recognised by IDV? > > > > Sorry - loads of questions! I'm going to hold off finding more data sets, I > > think I'm better off getting to grips with these for the time being. > > I agree. It is best to learn enough to be able to use the IDV effectively > before drowning oneself in data. > > re: > > The Mac is struggling a bit, when I try to do a 'flythrough' it freezes and > > the various displays start going wrong. Even if Paul's 10 GB current file > > could be loaded I suspect it would crash. I guess it's a case of finding > > more RAM (8GB?) > > Since everything in the IDV is inherently 3D, one needs to have a LOT of > memory > if one is trying to use large datasets. Our development machines here in > the UPC typically have 24 GB or more of RAM and we don't find that to be > too much :-) > > re: > > Many thanks, > > No worries. > Cheers, > > Tom > -- > **************************************************************************** > Unidata User Support UCAR Unidata Program > (303) 497-8642 P.O. Box 3000 > address@hidden Boulder, CO 80307 > ---------------------------------------------------------------------------- > Unidata HomePage http://www.unidata.ucar.edu > **************************************************************************** > Ticket Details =================== Ticket ID: IYO-548353 Department: Support IDV Priority: Normal Status: Open