[IDV #LPW-471935]: Plotting .hdf files in IDV

Alexa,

Yes, thanks for the clarification. (I think the ordering of our messages got
jumbled there.)

I see what you are saying, and when I load each individual file separately I can
see the data are definitely not the same so something is amiss. We'll resume
tomorrow.

Best,

Unidata IDV Support

> Hi there — thank you for for your reply. Using your syntax below, I tried 
> aggregating three files (edited script attached) — different files this time. 
> Again, the files are read into IDV with the correct time stamps, and I can 
> toggle between the times, but the strange thing is the plot does not change 
> with time. It’s like it’s only plotting one time. -Alexa
> 
> 
> 
> 
> 
> > On Mar 31, 2016, at 3:46 PM, Unidata IDV Support <address@hidden> wrote:
> >
> > Alexa,
> >
> > Great! Glad we are making progress and also that you are hanging in there. 
> > This
> > stuff is not so easy.
> >
> > Replace the current values element with something like this:
> >
> >   <values>0 3 11</values>
> >
> > But if that is too onerous because you have many file, we will have to go 
> > via
> > the time extraction route. Let me know...
> >
> > Best,
> >
> > Unidata IDV Support
> >
> >> Hello — this looks great, and I appreciate your help with this. Your ncml 
> >> script worked for the two test files and the times look right. However, 
> >> since we have some missing satellite images, not all the files are spaced 
> >> exactly 10 mins apart. Is there a way to specify time gaps between 
> >> individual files begin aggregated? Otherwise, perhaps extracting the time 
> >> from the file name would be good route. -Alexa
> >>
> >>
> >>> On Mar 31, 2016, at 3:29 PM, Unidata IDV Support <address@hidden> wrote:
> >>>
> >>> Hi again,
> >>>
> >>> The embedded NcML is a bit hard to read so attached, you will find
> >>> that same NcML file.
> >>>
> >>> Best,
> >>>
> >>> Unidata IDV Support
> >>>
> >>>> Hi Alexa,
> >>>>
> >>>> It is a little tricky but you can fix these problems with a bit of
> >>>> NcML. To get us going, let's look at the following NcML which can be
> >>>> read into the IDV and will allow you to view the
> >>>> `channel_14_brightness_temperature' over time. This file should be
> >>>> located next to your `hdf' files. Please read the comments in the NcML
> >>>> for more information about what is going on here.
> >>>>
> >>>> ,----
> >>>> | <?xml version="1.0" encoding="UTF-8"?>
> >>>> | <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
> >>>> |   <!-- Create a time coordinate variable that will be used for the 
> >>>> aggregation. -->
> >>>> |   <variable name="time" type="int" shape="time" >
> >>>> |     <!-- Let's add some units. Alexa: please make sure these units are 
> >>>> correct. -->
> >>>> |     <attribute name="units" value="minutes since 2014-04-04 19:09"/>
> >>>> |     <!-- Specify this variable as a time coordinate -->
> >>>> |     <attribute name="_CoordinateAxisType" value="Time" />
> >>>> |     <!-- Increment each file listed below by 10 minutes. Alexa, please 
> >>>> make sure this -->
> >>>> |     <!-- assumption about the times is correct. -->
> >>>> |     <values start="0" increment="10" />
> >>>> |   </variable>
> >>>> |   <!--   Specify the coordinates of time lat lon for this one 
> >>>> variable. Please use -->
> >>>> |   <!-- this as an example for other variables you are interersted in. 
> >>>> In other -->
> >>>> |   <!-- words, you can copy and paste this variable NcML element for 
> >>>> your other -->
> >>>> |   <!-- variables. -->
> >>>> |   <variable name="channel_14_brightness_temperature" shape="lines 
> >>>> elements" type="short">
> >>>> |     <attribute name="coordinates" value="time pixel_latitude 
> >>>> pixel_longitude" />
> >>>> |   </variable>
> >>>> |   <!-- Now you are ready to do your aggregation, which is the easy 
> >>>> part at this point -->
> >>>> |   <aggregation dimName="time" type="joinNew">
> >>>> |     <variableAgg name="T"/>
> >>>> |     <netcdf location="geocatL1.MTSAT-1R.2014044.190900.hdf"/>
> >>>> |     <netcdf location="geocatL1.MTSAT-1R.2014044.191900.hdf"/>
> >>>> |   </aggregation>
> >>>> | </netcdf>
> >>>> `----
> >>>>
> >>>> In summary, this NcML should aggregate over time the two of HDF files
> >>>> you provided. You will see only one variable that is aggregated over
> >>>> time; `channel_14_brightness_temperature'.  I'll leave it up to you to
> >>>> do the others though do not hesitate to ask for help.
> >>>>
> >>>> Also, if interested, there are also fancier tricks we can do here such
> >>>> as NcML can be smart enough to extract the times from the file names.
> >>>>
> >>>> Best,
> >>>>
> >>>> Unidata IDV Support
> >>>>
> >>>>> Ok sounds promising. Here is the link to another file, which should 
> >>>>> differ only in time — 
> >>>>> https://drive.google.com/file/d/0B1jVlP9ZfAZCRDVyczU3N2NMbFU/view?usp=sharing
> >>>>>    -Alexa
> >>>>>
> >>>>>> On Mar 30, 2016, at 4:49 PM, Unidata IDV Support <address@hidden> 
> >>>>>> wrote:
> >>>>>>
> >>>>>> Alexa,
> >>>>>>
> >>>>>> Indeed we may be able to patch things up with a bit of ncml. I only 
> >>>>>> found one
> >>>>>> file at the drive.google location. Would it be possible to see more so 
> >>>>>> that we
> >>>>>> have something to aggregate?
> >>>>>>
> >>>>>> Best,
> >>>>>>
> >>>>>> Unidata IDV Support
> >>>>>>
> >>>>>>> Hello IDV Support,
> >>>>>>>
> >>>>>>> I am working on reading in a number of HDF files using ‘aggregate 
> >>>>>>> grids by time’ or similar. I am able to read the files in 
> >>>>>>> individually without a problem, but it looks like the time variable 
> >>>>>>> is not recognized. The error message is "Grid data source failed 
> >>>>>>> making data set….Dimension time does not exist”. Any ideas for how to 
> >>>>>>> specify the time variable? Could this be achieved with an .ncml 
> >>>>>>> script?
> >>>>>>>
> >>>>>>> Example file is located here: 
> >>>>>>> https://drive.google.com/file/d/0B1jVlP9ZfAZCRFhkRVM2aVVRVGc/view?usp=sharing
> >>>>>>>
> >>>>>>> All the best
> >>>>>>>
> >>>>>>> Alexa
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>> Ticket Details
> >>>>>> ===================
> >>>>>> Ticket ID: LPW-471935
> >>>>>> Department: Support IDV
> >>>>>> Priority: Normal
> >>>>>> Status: Closed
> >>>>>>
> >>>>>
> >>>>>
> >>>>
> >>>
> >>>
> >>> Ticket Details
> >>> ===================
> >>> Ticket ID: LPW-471935
> >>> Department: Support IDV
> >>> Priority: Normal
> >>> Status: Closed<alexa.ncml>
> >>
> >>
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: LPW-471935
> > Department: Support IDV
> > Priority: Normal
> > Status: Closed
> >
> 
> 
> 


Ticket Details
===================
Ticket ID: LPW-471935
Department: Support IDV
Priority: Normal
Status: Open