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[IDV #LPW-471935]: Plotting .hdf files in IDV
- Subject: [IDV #LPW-471935]: Plotting .hdf files in IDV
- Date: Thu, 31 Mar 2016 16:46:39 -0600
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