On Tue, Aug 14, 2012 at 7:01 AM, Roy Mendelssohn <roy.mendelssohn@noaa.gov> wrote:
Hi:
You would do a lot better realizing that the file you are accessing, while built on hdf5, is a netcdf4 file, which has special structures and semantics that would be better understood using the netcdf4 libraries directly. There is a Windows dll available that works in Visual Studio. I do not know if that will work with C# (it is a C library AFAIK). By using the netcdf4 libraries, you will get the type of information you are after. At the end is the header dump for your file:
See: http://www.unidata.ucar.edu/software/netcdf/win_netcdf/
Also, if I knew where you get your data, there may well be a service available that would simplify access.
-Roy M.
netcdf PREVIMER_WW3-AQUITAINE-200M_20120101T00Z {
dimensions:
time = UNLIMITED ; // (1 currently)
longitude = 561 ;
latitude = 1501 ;
variables:
double time(time) ;
time:units = "days since 1990-01-01T00:00:00Z" ;
time:long_name = "julian day (UT)" ;
time:standard_name = "time" ;
time:conventions = "relative julian days with decimal part (as parts of the day )" ;
time:scale_factor = 1.f ;
time:add_offset = 0.f ;
time:valid_min = 0.f ;
time:valid_max = 30000.f ;
time:axis = "T" ;
float longitude(longitude) ;
longitude:units = "degrees_east" ;
longitude:long_name = "longitude" ;
longitude:standard_name = "longitude" ;
longitude:valid_min = -180.f ;
longitude:valid_max = 180.f ;
longitude:axis = "X" ;
float latitude(latitude) ;
latitude:units = "degrees_north" ;
latitude:long_name = "latitude" ;
latitude:standard_name = "latitude" ;
latitude:valid_min = -90.f ;
latitude:valid_max = 90.f ;
latitude:axis = "Y" ;
short uabr(time, latitude, longitude) ;
uabr:units = "m" ;
uabr:_FillValue = -32767s ;
uabr:long_name = "rms_of_bottom_displacement_amplitude_zonal" ;
uabr:standard_name = "rms_of_bottom_displacement_amplitude_zonal" ;
uabr:scale_factor = 0.01f ;
uabr:add_offset = 0.f ;
uabr:valid_min = -18000s ;
uabr:valid_max = 18000s ;
short vabr(time, latitude, longitude) ;
vabr:units = "m" ;
vabr:_FillValue = -32767s ;
vabr:long_name = "rms_of_bottom_displacement_amplitude_meridional" ;
vabr:standard_name = "rms_of_bottom_displacement_amplitude_meridional" ;
vabr:scale_factor = 0.01f ;
vabr:add_offset = 0.f ;
vabr:valid_min = -18000s ;
vabr:valid_max = 18000s ;
short CgE(time, latitude, longitude) ;
CgE:units = "kW/m" ;
CgE:_FillValue = -32767s ;
CgE:long_name = "Wave_energy_flux" ;
CgE:standard_name = "sea_surface_wind_wave_energy_flux" ;
CgE:scale_factor = 0.1f ;
CgE:add_offset = 0.f ;
CgE:valid_min = 0s ;
CgE:valid_max = 9990s ;
short foc(time, latitude, longitude) ;
foc:units = "W/m2" ;
foc:_FillValue = -32767s ;
foc:long_name = "wave_to_ocean_energy_flux" ;
foc:standard_name = "wave_to_ocean_energy_flux" ;
foc:scale_factor = 0.1f ;
foc:add_offset = 0.f ;
foc:valid_min = 0s ;
foc:valid_max = 9990s ;
short hs(time, latitude, longitude) ;
hs:units = "m" ;
hs:_FillValue = -32767s ;
hs:long_name = "significant_wave_height" ;
hs:standard_name = "significant_height_of_wind_and_swell_waves" ;
hs:scale_factor = 0.002f ;
hs:add_offset = 0.f ;
hs:valid_min = 0s ;
hs:valid_max = 32000s ;
short hs0(time, latitude, longitude) ;
hs0:units = "m" ;
hs0:_FillValue = -32767s ;
hs0:long_name = "significant_wave_height_partition_0" ;
hs0:standard_name = "sea_surface_swell_0_wave_significant_height" ;
hs0:scale_factor = 0.002f ;
hs0:add_offset = 0.f ;
hs0:valid_min = 0s ;
hs0:valid_max = 32000s ;
short hs1(time, latitude, longitude) ;
hs1:units = "m" ;
hs1:_FillValue = -32767s ;
hs1:long_name = "significant_wave_height_partition_1" ;
hs1:standard_name = "sea_surface_swell_1_wave_significant_height" ;
hs1:scale_factor = 0.002f ;
hs1:add_offset = 0.f ;
hs1:valid_min = 0s ;
hs1:valid_max = 32000s ;
short hs2(time, latitude, longitude) ;
hs2:units = "m" ;
hs2:_FillValue = -32767s ;
hs2:long_name = "significant_wave_height_partition_2" ;
hs2:standard_name = "sea_surface_swell_2_wave_significant_height" ;
hs2:scale_factor = 0.002f ;
hs2:add_offset = 0.f ;
hs2:valid_min = 0s ;
hs2:valid_max = 32000s ;
short mssx(time, latitude, longitude) ;
mssx:units = "1" ;
mssx:_FillValue = -32767s ;
mssx:long_name = "east_west_mean_square_slope" ;
mssx:standard_name = "east_west_mean_square_slope" ;
mssx:scale_factor = 1.e-05f ;
mssx:add_offset = 0.f ;
mssx:valid_min = 0s ;
mssx:valid_max = 30000s ;
short mssy(time, latitude, longitude) ;
mssy:units = "1" ;
mssy:_FillValue = -32767s ;
mssy:long_name = "south_north_mean_square_slope" ;
mssy:standard_name = "south_north_mean_square_slope" ;
mssy:scale_factor = 1.e-05f ;
mssy:add_offset = 0.f ;
mssy:valid_min = 0s ;
mssy:valid_max = 30000s ;
short spr(time, latitude, longitude) ;
spr:units = "degree" ;
spr:_FillValue = -32767s ;
spr:long_name = "directional_spread" ;
spr:standard_name = "sea_surface_wave_directional_spread" ;
spr:scale_factor = 0.1f ;
spr:add_offset = 0.f ;
spr:valid_min = 0s ;
spr:valid_max = 900s ;
short t(time, latitude, longitude) ;
t:units = "s" ;
t:_FillValue = -32767s ;
t:long_name = "mean_period_Tm01" ;
t:standard_name = "sea_surface_wind_wave_mean_period_from_variance_spectral_density_first_frequency_moment" ;
t:scale_factor = 0.01f ;
t:add_offset = 0.f ;
t:valid_min = 0s ;
t:valid_max = 5000s ;
short t02(time, latitude, longitude) ;
t02:units = "s" ;
t02:_FillValue = -32767s ;
t02:long_name = "mean_period_Tm02" ;
t02:standard_name = "sea_surface_wind_wave_mean_period_from_variance_spectral_density_second_frequency_moment" ;
t02:scale_factor = 0.01f ;
t02:add_offset = 0.f ;
t02:valid_min = 0s ;
t02:valid_max = 5000s ;
short utus(time, latitude, longitude) ;
utus:units = "m2s-1" ;
utus:_FillValue = -32767s ;
utus:long_name = "eastward_Stokes_transport" ;
utus:standard_name = "eastward_Stokes_transport" ;
utus:scale_factor = 0.001f ;
utus:add_offset = 0.f ;
utus:valid_min = -9900s ;
utus:valid_max = 9990s ;
short vtus(time, latitude, longitude) ;
vtus:units = "m2s-1" ;
vtus:_FillValue = -32767s ;
vtus:long_name = "northward_Stokes_transport" ;
vtus:standard_name = "northward_Stokes_transport" ;
vtus:scale_factor = 0.001f ;
vtus:add_offset = 0.f ;
vtus:valid_min = -9900s ;
vtus:valid_max = 9990s ;
short uubr(time, latitude, longitude) ;
uubr:units = "ms-1" ;
uubr:_FillValue = -32767s ;
uubr:long_name = "rms_of_bottom_velocity_amplitude_zonal" ;
uubr:standard_name = "rms_of_bottom_velocity_amplitude_zonal" ;
uubr:scale_factor = 0.01f ;
uubr:add_offset = 0.f ;
uubr:valid_min = -18000s ;
uubr:valid_max = 18000s ;
short vubr(time, latitude, longitude) ;
vubr:units = "ms-1" ;
vubr:_FillValue = -32767s ;
vubr:long_name = "rms_of_bottom_velocity_amplitude_meridional" ;
vubr:standard_name = "rms_of_bottom_velocity_amplitude_meridional" ;
vubr:scale_factor = 0.01f ;
vubr:add_offset = 0.f ;
vubr:valid_min = -18000s ;
vubr:valid_max = 18000s ;
short uuss(time, latitude, longitude) ;
uuss:units = "m/s" ;
uuss:_FillValue = -32767s ;
uuss:long_name = "eastward_surface_Stokes_drift" ;
uuss:standard_name = "eastward_surface_Stokes_drift" ;
uuss:scale_factor = 0.0005f ;
uuss:add_offset = 0.f ;
uuss:valid_min = -9900s ;
uuss:valid_max = 9900s ;
short vuss(time, latitude, longitude) ;
vuss:units = "m/s" ;
vuss:_FillValue = -32767s ;
vuss:long_name = "northward_surface_Stokes_drift" ;
vuss:standard_name = "northward_surface_Stokes_drift" ;
vuss:scale_factor = 0.0005f ;
vuss:add_offset = 0.f ;
vuss:valid_min = -9900s ;
vuss:valid_max = 9900s ;
short uust(time, latitude, longitude) ;
uust:units = "m/s" ;
uust:_FillValue = -32767s ;
uust:long_name = "eastward_friction_velocity" ;
uust:standard_name = "eastward_friction_velocity" ;
uust:scale_factor = 0.01f ;
uust:add_offset = 0.f ;
uust:valid_min = -9900s ;
uust:valid_max = 9900s ;
short vust(time, latitude, longitude) ;
vust:units = "m/s" ;
vust:_FillValue = -32767s ;
vust:long_name = "northward_friction_velocity" ;
vust:standard_name = "northward_friction_velocity" ;
vust:scale_factor = 0.01f ;
vust:add_offset = 0.f ;
vust:valid_min = -9900s ;
vust:valid_max = 9900s ;
short U10(time, latitude, longitude) ;
U10:units = "m/s" ;
U10:_FillValue = -32767s ;
U10:long_name = "eastward_wind" ;
U10:standard_name = "eastward_wind" ;
U10:scale_factor = 0.1f ;
U10:add_offset = 0.f ;
U10:valid_min = -990s ;
U10:valid_max = 990s ;
short V10(time, latitude, longitude) ;
V10:units = "m/s" ;
V10:_FillValue = -32767s ;
V10:long_name = "northward_wind" ;
V10:standard_name = "northward_wind" ;
V10:scale_factor = 0.1f ;
V10:add_offset = 0.f ;
V10:valid_min = -990s ;
V10:valid_max = 990s ;
short dir(time, latitude, longitude) ;
dir:units = "degree" ;
dir:_FillValue = -32767s ;
dir:long_name = "wave_mean_direction" ;
dir:standard_name = "sea_surface_wave_from_direction" ;
dir:scale_factor = 0.1f ;
dir:add_offset = 0.f ;
dir:valid_min = 0s ;
dir:valid_max = 3600s ;
short dp(time, latitude, longitude) ;
dp:units = "degree" ;
dp:_FillValue = -32767s ;
dp:long_name = "peak_direction" ;
dp:standard_name = "peak_direction" ;
dp:scale_factor = 1.f ;
dp:add_offset = 0.f ;
dp:valid_min = 0s ;
dp:valid_max = 360s ;
short th0(time, latitude, longitude) ;
th0:units = "degree" ;
th0:_FillValue = -32767s ;
th0:long_name = "mean_direction_swell_partition_0" ;
th0:standard_name = "sea_surface_swell_0_wave_from_mean_direction" ;
th0:scale_factor = 1.f ;
th0:add_offset = 0.f ;
th0:valid_min = 0s ;
th0:valid_max = 360s ;
short th1(time, latitude, longitude) ;
th1:units = "degree" ;
th1:_FillValue = -32767s ;
th1:long_name = "mean_direction_swell_partition_1" ;
th1:standard_name = "sea_surface_swell_1_wave_from_mean_direction" ;
th1:scale_factor = 1.f ;
th1:add_offset = 0.f ;
th1:valid_min = 0s ;
th1:valid_max = 360s ;
short th2(time, latitude, longitude) ;
th2:units = "degree" ;
th2:_FillValue = -32767s ;
th2:long_name = "mean_direction_swell_partition_2" ;
th2:standard_name = "sea_surface_swell_2_wave_from_mean_direction" ;
th2:scale_factor = 1.f ;
th2:add_offset = 0.f ;
th2:valid_min = 0s ;
th2:valid_max = 360s ;
short fp(time, latitude, longitude) ;
fp:units = "s-1" ;
fp:_FillValue = -32767s ;
fp:long_name = "wave_peak_frequency" ;
fp:standard_name = "sea_surface_wave_peak_frequency" ;
fp:scale_factor = 0.001f ;
fp:add_offset = 0.f ;
fp:valid_min = 0s ;
fp:valid_max = 10000s ;
short tp0(time, latitude, longitude) ;
tp0:units = "s" ;
tp0:_FillValue = -32767s ;
tp0:long_name = "peak_period_swell_partition_0" ;
tp0:standard_name = "sea_surface_swell_0_wave_peak_period" ;
tp0:scale_factor = 0.01f ;
tp0:add_offset = 0.f ;
tp0:valid_min = 0s ;
tp0:valid_max = 10000s ;
short tp1(time, latitude, longitude) ;
tp1:units = "s" ;
tp1:_FillValue = -32767s ;
tp1:long_name = "peak_period_swell_partition_1" ;
tp1:standard_name = "sea_surface_swell_1_wave_peak_period" ;
tp1:scale_factor = 0.01f ;
tp1:add_offset = 0.f ;
tp1:valid_min = 0s ;
tp1:valid_max = 10000s ;
short tp2(time, latitude, longitude) ;
tp2:units = "s" ;
tp2:_FillValue = -32767s ;
tp2:long_name = "peak_period_swell_partition_2" ;
tp2:standard_name = "sea_surface_swell_2_wave_peak_period" ;
tp2:scale_factor = 0.01f ;
tp2:add_offset = 0.f ;
tp2:valid_min = 0s ;
tp2:valid_max = 10000s ;
short U(time, latitude, longitude) ;
U:units = "m/s" ;
U:_FillValue = -32767s ;
U:long_name = "eastward_current" ;
U:standard_name = "eastward_current" ;
U:scale_factor = 0.01f ;
U:add_offset = 0.f ;
U:valid_min = -990s ;
U:valid_max = 990s ;
short V(time, latitude, longitude) ;
V:units = "m/s" ;
V:_FillValue = -32767s ;
V:long_name = "northward_current" ;
V:standard_name = "northward_current" ;
V:scale_factor = 0.01f ;
V:add_offset = 0.f ;
V:valid_min = -990s ;
V:valid_max = 990s ;
// global attributes:
:data_type = "OCO straight grid" ;
:format_version = "1.2" ;
:title = "WAVEWATCH-III FORECAST" ;
:Conventions = "CF-1.5" ;
:netcdf_version = "4.11" ;
:product_name = "PREVIMER_WW3-AQUITAINE-200M_20120101T00Z.nc" ;
:software_version = "3.14-Ifremer-SHOM_rev65" ;
:references = "http://wwz.ifremer.fr/iowaga/" ;
:source = "MODEL WAVEWATCH III (R) NORGAS-UG" ;
:comment = "" ;
:area = "AQUITAINE-200M" ;
:easting = "longitude" ;
:northing = "latitude" ;
:grid_projection = "n/a" ;
:southernmost_latitude = " 43.2999992" ;
:northernmost_latitude = " 45.7999992" ;
:latitude_resolution = " 0.0016667" ;
:westernmost_longitude = " -1.9000000" ;
:easternmost_longitude = " -0.5000000" ;
:longitude_resolution = " 0.0025000" ;
:minimum_altitude = "-12000 m" ;
:maximum_altitude = "9000 m" ;
:altitude_resolution = "n/a" ;
:field_type = "hourly" ;
:forecast_range = "6 day forecast" ;
:forecast_type = "forecast" ;
:institution = "SHOM and Ifremer" ;
:institution_references = "http://www.previmer.org/" ;
:data_centre = "IFREMER OCO DATA CENTER" ;
:data_centre_references = "http://www.previmer.org/" ;
:contact = "cdoco-exploit@ifremer.fr" ;
:distribution_statement = "No restrictions" ;
:operational_status = "operational" ;
:quality_index = "0" ;
:creation_date = "2012-01-02T05:19:15Z" ;
:product_version = "1.0" ;
:history = "2012-01-02T05:19:15Z : Creation,2012-01-02T05:48:57Z : Interpolation in regular grid" ;
:run_time = "2012-01-02T05:19:15Z" ;
:date_cycle = "2012010112" ;
:forcing_wind = "wind_cel25" ;
:forcing_ice = "no" ;
:forcing_level = "MARSD1_lev" ;
:forcing_current = "MARSD1_cur" ;
:SWELLF = "0.1" ;
:ZWND = "15." ;
:IQTYPE = "3" ;
:NDEPTH = "3" ;
:BETAMAX = "1.25" ;
:EXPFSN = "F" ;
:GAMMA = "0.15" ;
:CICE0 = "0.25" ;
:CICEN = "0.75" ;
:FLAGTR = "4" ;
:NX\*SX = "360." ;
:start_date = "2012-01-01T00:00:00Z" ;
:stop_date = "2012-01-01T00:00:00Z" ;
}
On Aug 13, 2012, at 3:34 PM, Mathieu wrote:
Dear Gerd,
Thank you for your python code, it is like gold bar for me!
Okay, so it looks very simple now.
I’ll port it to c# soon, and report you my result (but I’m feeling optimistic)
By “projection & matrix information”, I was meaning basically :
- “Projection” : The 6 geographic coefficients, called GeoTransform in GDAL, that define the data location. These are 6 numbers, but practically only 4 are used
0 left position of the datas
1 size of one cell in X direction
2 rotation (rarely used)
3 Top position of the datas
4 rotation (rarely used)
5 size of one cell in Y direction
I’m sure you see what I’m talking about. Usually it is not enough since the projection type should be known (Lambert, UTM, Polyconic, Mercator ...) but in my case it is just Lat/Lon WGS84
How to retreive these coefficients?
- “matrix information”
I was meaning the data buffer or array itself, but OK you give this in your sample!
Best regards,
Mathieu
From: Gerd Heber
Sent: Monday, August 13, 2012 3:47 PM
To: 'HDF Users Discussion List'
Subject: Re: [Hdf-forum] Can Hdf5DotNet replace GDAL# in my case?
Mathieu, yes you can. Here’s a simple example that reads the dataset at ‘/hs’ and prints
its dimensions and values. (You’ll need IronPython http://ironpython.net/\)
I’m not sure what you mean by “projection and matrix information”. Where do
they live? In attributes? You can look at the file in HDFView
(http://www.hdfgroup.org/hdf-java-html/hdfview/\)...
Cheers, G.
From: hdf-forum-bounces@hdfgroup.org [mailto:hdf-forum-bounces@hdfgroup.org] On Behalf Of Mathieu
Sent: Sunday, August 12, 2012 7:39 AM
To: hdf-forum@hdfgroup.org
Subject: [Hdf-forum] Can Hdf5DotNet replace GDAL# in my case?
Dear all,
I am a windows C# developer, I develop a weather forecast web site for french surfers.
I am working with a oceanographic data provider since 3 years, and until now I was using Gdal# to read their HDF (.nc) data.
Recently, this data provider released a new product, and used a new version of HDF : V5.
GDAL# cannot read these data. After some researchs on the web and discussions with the data provider, Gfdal#'s HDF library is too old. Gdal does not plan to update it in a near future.
As a consequence I am looking for an alternative library to read HDF data.
Then I found HDF5DotNet.
I have started to study the library, but I fell I will have to invest a lot to adapt my tools to this library.
That's why before to start working on HDF5DotNet, I would like to ensure that this library is able to read these data I want to be compatible with.
So my request is :
Could anybody who is confortable with HDF5DotNet try to open this file with this library?
I know it is not a common request, but it would save me so much time!
The sample file is here :
Spot non trouvé!
(It is quiet big, 54Mo, but the server has a quiet good bandwidth)
Basically my need is to :
- Read projection and matrix information (projection is just position of the grid and cell size/size of the grid)
- Read the band "hs" (there are other intersecting datasets but validating this one is enough)
In advance, thanks
Mathieu
_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@hdfgroup.org
http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@hdfgroup.org
http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
**********************
"The contents of this message do not reflect any position of the U.S. Government or NOAA."
**********************
Roy Mendelssohn
Supervisory Operations Research Analyst
NOAA/NMFS
Environmental Research Division
Southwest Fisheries Science Center
1352 Lighthouse Avenue
Pacific Grove, CA 93950-2097
e-mail: Roy.Mendelssohn@noaa.gov (Note new e-mail address)
voice: (831)-648-9029
fax: (831)-648-8440
www: http://www.pfeg.noaa.gov/
"Old age and treachery will overcome youth and skill."
"From those who have been given much, much will be expected"
"the arc of the moral universe is long, but it bends toward justice" -MLK Jr.
_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@hdfgroup.org
http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
