Panoply uses NetCDF-Java underneath.
The variables you see are constructed by NetCDF-Java.
NetCDF-Java parses StructMetadata.
For Python, which is based on NetCDF-C, you need to parse StructMetadata.0 string to reconstruct coordinate variables by yourself.
We provide some Python examples at Comprehensive Examples for handling the metadata using netcdf4-python.
For example, you can parse the StructMetadata using Python regular expression like below and construct lat/lon
and visualize it on map.
We'll provide the complete Python LandSat 7 example later at hdfeos.org.
···
From: Hdf-forum [mailto:hdf-forum-bounces@lists.hdfgroup.org] On Behalf Of Mcgibbney, Lewis J (398M)
Sent: Thursday, December 04, 2014 10:51 AM
To: HDF Users Discussion List
Subject: Re: [Hdf-forum] Extracting Group Variables from Landsat 7 HDF-EOS
Hi,
No it is generated by Panoply [0], however I can see the variable fields when I print the Dataset object.
I just can't see how to actually access them cleanly.
I resorted to the following which is horrible, probably inconsistent in it's operation across various HDF4 from Landsat 7 and just downright nasty
str(f.__dict__['StructMetadata.0']).split()
This above gives me the StructMetadata.0 element of the dataset dictionary as a list. I can then navigate to the index within that list and grab the variable I require e.g. UpperLeftPointMtrs
Do you have any better suggestions. I anticipate that this hack will come back to bite me pretty soon.
Thank you very much for any information.
lewis
[0] NASA GISS: Panoply 5 netCDF, HDF and GRIB Data Viewer
Dr. Lewis John McGibbney PhD, B.Sc., MAGU
Engineering Applications Software Engineer Level 2
Computer Science for Data Intensive Systems Group 398M
Jet Propulsion Laboratory
California Institute of Technology
4800 Oak Grove Drive
Pasadena, California 91109-8099
Mail Stop : 158-256C
Tel: (+1) (818)-393-7402
Cell: (+1) (626)-487-3476
Fax: (+1) (818)-393-1190
Email: lewis.j.mcgibbney@jpl.nasa.gov<mailto:lewis.j.mcgibbney@jpl.nasa.gov>
[cid:image001.png@01D00FB1.97386D30]
Dare Mighty Things
From: "H. Joe Lee" <hyoklee@hdfgroup.org<mailto:hyoklee@hdfgroup.org>>
Reply-To: HDF Users Discussion List <hdf-forum@lists.hdfgroup.org<mailto:hdf-forum@lists.hdfgroup.org>>
Date: Thursday, December 4, 2014 at 7:09 AM
To: HDF Users Discussion List <hdf-forum@lists.hdfgroup.org<mailto:hdf-forum@lists.hdfgroup.org>>
Subject: Re: [Hdf-forum] Extracting Group Variables from Landsat 7 HDF-EOS
Hi, Lewis!
Is screen shot generated from ToolsUI (Netcdf-Java)?
--
Save the Earth. Save Earth data in HDF-EOS. Save Big data in HDF.
On Wed, Dec 3, 2014 at 4:40 PM, Mcgibbney, Lewis J (398M) <Lewis.J.Mcgibbney@jpl.nasa.gov<mailto:Lewis.J.Mcgibbney@jpl.nasa.gov>> wrote:
Hi Folks,
I am really struggling to extract certain Group variables from a HDF4 hdf-eos Landsat 7 file.
I am using the netcdf4-python driver [0] in order to achieve this task. I've installed the chain of dependencies fine.
The Group Variables which I cannot seem to access are included within the attached .png. E.g. Projection, UpperLeftPointMtrs, LowerRightMtrs and SphereCode.
I can however view them when I read in the HDF4 file as follows
f = Dataset(hdfFile)
print f
<output>
...
GROUP=GridStructure
GROUP=GRID_1
GridName="Grid"
XDim=8001
YDim=7271
UpperLeftPointMtrs=(310185.000000,4575015.000000)
LowerRightMtrs=(550215.000000,4356885.000000)
...
</output>
Can someone please advise me as how I can extract the Group Variables as I've explained above?
Thank you very much in advance for any assistance.
Best
Lewis
[0] netCDF4 API documentation
Dr. Lewis John McGibbney PhD, B.Sc., MAGU
Engineering Applications Software Engineer Level 2
Computer Science for Data Intensive Systems Group 398M
Jet Propulsion Laboratory
California Institute of Technology
4800 Oak Grove Drive
Pasadena, California 91109-8099
Mail Stop : 158-256C
Tel: (+1) (818)-393-7402<tel:%28%2B1%29%20%28818%29-393-7402>
Cell: (+1) (626)-487-3476<tel:%28%2B1%29%20%28626%29-487-3476>
Fax: (+1) (818)-393-1190<tel:%28%2B1%29%20%28818%29-393-1190>
Email: lewis.j.mcgibbney@jpl.nasa.gov<mailto:lewis.j.mcgibbney@jpl.nasa.gov>
[cid:image001.png@01D00FB1.97386D30]
Dare Mighty Things
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