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Hi, Thank you for the reports. This is of course a feature of remote data, that over time severs are changed at the various institutions which serve data, so that the URL's change. (And of course it's also an issue with documentation, keeping links up to date). I'm working on updating these scripts and the documentation. I've attached "opendap_demo.jnl" which will replace the Ferret script dods_demo.jnl, and the on-line tutorial will also be updated to match this. OPeNDAP is the newer name for DODS. You can put this in any local directory, and run it from Ferret, reading the text and viewing the images as it runs. yes? go opendap_demo We will be working through the documentation and will be correcting these out-of-date url's. Ansley On 2/5/2016 11:09 AM, Nguyen Tuyet
wrote:
Hi all,I try to run dods wind with this command:USE "http://ferret.pmel.noaa.gov/cgi-bin/nph-dods/data/TAO_gridded.nc" |
\cancel mode verify ! set initial demo state cancel data/all cancel region ! dods_demo.jnl *kob* 5/99 ! customized for IPRC presentation 9/99 *sh* ! ! Description: Demo: how to use Ferret and OPeNDAP to access remote Datasets ! set mode verify ! ********************************************************* ! DEMO: Using Ferret and DODS to access remote data sets ! ********************************************************* ! First we will examine the COADS climatology dataset from the Pacific ! Marine Environmental Laboratory (PMEL) in Seattle, Washington. ! Note: Once the dataset has been initialized from the remote site, ! using the dataset is exactly the same as if it were local PAUSE ! ********************************************************* set data "http://ferret.pmel.noaa.gov/thredds/dodsC/data/PMEL/coads_climatology.nc"; show data ! SHOW DATA verifies that this is indeed a remote dataset ! ! Now let's look at a color contour of Sea Surface Temperature PAUSE ! ********************************************************* fill/t="16-jul" sst go land ! Next, let's look at a subregion of the SST. ! Note: Higher data access speed may be noticed due to data caching by Ferret PAUSE ! ********************************************************* go basemap x=130e:170w y=30N:70N 5 fill/overlay/t="16-jul"/x=140e:180e/y=40N:65N sst ! Remote data has full random access. Here we will plot the evolution of SST ! averaged over the Equatorial waveguide (an XT section) PAUSE ! ********************************************************* fill/x=140e:180e/l=1:24 sst[y=5s:5n@ave] ! Now, let's use a different SST dataset from the Earth System Research Laboratory ! (ESRL) in Boulder, Colorado PAUSE ! ********************************************************* use "http://www.esrl.noaa.gov/psd/thredds/dodsC/Aggregations/OISSThires/sst.mean.nc"; show data 2 ! This data set contains weekly mean global SST grids prepared by ! Reynolds et. al. (see http://www.esrl.noaa.gov/psd/thredds/catalog.html) ! Let's look at the SST for June 15, 1989 PAUSE ! ********************************************************* fill/t="15-JUN-1989" sst[d=2] go fland ! Now, let's see where the June 15, 1998 Reynolds field (served from Boulder) ! exceeds the June climatological data (served from Seattle) ! This requires regridding the 2x2 degree COADS data to the 0.25x0.25 degree ! Reynolds grid PAUSE ! ********************************************************* let coads_on_reynolds = sst[d=1,g=sst[d=2]] let warmer = IF sst[d=2] GT coads_on_reynolds THEN 1 shade/x=80w:20e/y=0:80N/pal=black/levels/pattern=weave/t="15-jun-1989"/over warmer ! Next let's look at a dataset from NASA's Earth Observing system (EOS) HDF-EOS group. ! This data set is in HDF format. It contains surface data - wind stress, heat flux, ! humidity, precipitable water. ! Note that DODS gives Ferret format-independence -- the ability to read ! an HDF file PAUSE ! ********************************************************* use "http://measures.gsfc.nasa.gov/opendap/GSSTF/GSSTF.3/2008/GSSTF.3.2008.01.01.he5"; ! Let's look at the wind-stress vectors in the Indian Ocean PAUSE ! ********************************************************* vector/x=20:140/y=-60:30 STU, STV go fland ! Next lets examine some NOAA AVHRR data served by the University ! of Rhode Island, Graduate School of Oceanography (GSO). This ! data is in the form of 1024x1024 pixel images (1 megabyte per image) ! We will use this to illustrate the ability of Ferret and DODS to ! subsample -- making the data transfer much faster. PAUSE ! ********************************************************* use "http://satdat1.gso.uri.edu:80/opendap/AVHRR/Old_Pathfinder/Northwest_Atlantic/6km/raw/1999/1/f99001082417.hdf"; ! Performance greatly enhanced through use of strides shade/levels=v dsp_band_1[i=1:1024:4, j=1:1024:4] PAUSE ! We can see Florida and the Carribean islands, but they are upside down. ! Ferret can use the netCDF library to address this, with the /ORDER qualifier. cancel data f99001082417.hdf use/order=x-y "http://satdat1.gso.uri.edu:80/opendap/AVHRR/Old_Pathfinder/Northwest_Atlantic/6km/raw/1999/1/f99001082417.hdf"; ! The coordinate axes are just index values, but the longitude/latitude ranges are ! defined in global attributes. We can redefine the x and y axes to represent ! longitude and latitude axes. define axis/x=`..dsp_nav_earth_leflon`:`..dsp_nav_earth_ritlon`/npoints=1024/units=degrees_east `DSP_BAND_1,return=xaxis` define axis/y=`..dsp_nav_earth_botlat`:`..dsp_nav_earth_toplat`/npoints=1024/units=degrees_north `DSP_BAND_1,return=yaxis` shade/levels=v dsp_band_1[i=1:1024:4, j=1:1024:4] go land_detail