Hi Richard and THREDDS mailing list
Many thanks for your rapid response. And many thanks for finding the
school-boy error I was making! Looks like I need to check my URLs a bit closer.
So, now I'm specifying the correct syntax for the WCS request, I can get
GeoTIFF or NetCDF3 responses from THREDDS. However, I've noticed somethings
that baffling me further.
For a netCDF file with the following metadata:
netcdf Z:/thredds/smwtestwcs/chess_tas_196101_modified.nc {
dimensions:
time = 31;
x = 656;
y = 1057;
variables:
int crs;
:long_name = "coordinate_reference_system";
:grid_mapping_name = "transverse_mercator";
:EPSG_code = "EPSG:27700";
:semi_major_axis = 6377563.396; // double
:semi_minor_axis = 6356256.91; // double
:inverse_flattening = 299.3249646; // double
:latitude_of_projection_origin = 49.0; // double
:longitude_of_projection_origin = -2.0; // double
:false_easting = 400000.0; // double
:false_northing = -100000.0; // double
:scale_factor_at_projection_origin = 0.9996012717; // double
:_CoordinateTransformType = "Projection";
:_CoordinateAxes = "x y";
float lat(y=1057, x=656);
:_CoordinateAxisType = "Lat";
:long_name = "latitude of grid box centre";
:standard_name = "latitude";
:units = "degrees_north";
:_FillValue = -99999.0f; // float
:grid_mapping = "crs";
float lon(y=1057, x=656);
:_CoordinateAxisType = "Lon";
:long_name = "longitude of grid box centre";
:standard_name = "longitude";
:units = "degrees_east";
:_FillValue = -99999.0f; // float
:grid_mapping = "crs";
float tas(time=31, y=1057, x=656);
:_FillValue = -99999.0f; // float
:standard_name = "air_temperature";
:long_name = "Near-Surface Air Temperature";
:units = "K";
:grid_mapping = "crs";
:comment = "1.2m above surface";
:_CoordinateAxes = "x y time";
:_coordinates = "time y x";
float time(time=31);
:units = "days since 1961-01-01";
:calendar = "gregorian";
:long_name = "Time in days since 1961-01-01";
:_FillValue = -99999.0f; // float
:_CoordinateAxisType = "Time";
float x(x=656);
:long_name = "easting - OSGB36 grid reference";
:standard_name = "projection_x_coordinate";
:units = "m";
:point_spacing = "even";
:_FillValue = -99999.0f; // float
:_CoordinateAxisType = "GeoX";
float y(y=1057);
:long_name = "northing - OSGB36 grid reference";
:standard_name = "projection_y_coordinate";
:units = "m";
:point_spacing = "even";
:_FillValue = -99999.0f; // float
:_CoordinateAxisType = "GeoY";
// global attributes:
:title = "Near-Surface Air Temperature";
:description = "Near-Surface Air Temperature (K) at 1km resolution over Great
Britain";
:date_created = "2015-01-22";
:geospatial_lat_min = 49.770996f; // float
:geospatial_lat_max = 59.395187f; // float
:geospatial_lon_min = -9.004521f; // float
:geospatial_lon_max = 2.491239f; // float
:time_coverage_start = "1961-01-01";
:time_coverage_end = "1961-01-31";
:Conventions = "CF-1.6";
:NCO = "4.3.7";
:version = "v1.0";
:featureType = "GRID";
}
I can get a NetCDF3 file returned when I request the tas variable but not a
GeoTIFF file. Furthermore, if I request NetCDF3 or GeoTIFF files for the lon
and lat variables I just get error messages saying the web page is not
available.
Is there an obvious reason why? Do I need to include additional elements in
the netCDF metadata? Or am I doing something else wrong?
Many thanks for any help anyone can provide, best wishes, Simon.
>-----Original Message-----
>From: Signell, Richard [mailto:rsignell@xxxxxxxx]
>Sent: 02 October 2015 13:22
>To: Wright, Simon M. <smw@xxxxxxxxx>
>Cc: thredds@xxxxxxxxxxxxxxxx
>Subject: Re: [thredds] Can't get THREDDS WCS GetCoverage to work
>
>Simon,
>
>I think you just don't have your syntax quite right -- you need to specify
>"coverage=tas".
>
>So instead of this:
>http://localhost:8080/thredds/wcs/smwtestwcs/chess_tas_196101_modified.nc?serv
>ice=WCS&version=1.0.0&request=GetCoverage=tas&time=1961-01-
>31T00:00:00Z&format=GeoTIFF
>
>Try this:
>http://localhost:8080/thredds/wcs/smwtestwcs/chess_tas_196101_modified.nc?serv
>ice=WCS&version=1.0.0&request=GetCoverage&coverage=tas&time=1961-01-
>31T00:00:00Z&format=GeoTIFF
>
>
>Just to see if there was some issue with the latest release, I tried a WCS
>GetCoverage request on our TDS 4.6.3 server and it seems okay:
>
>wget -O test.tif
>"http://geoport-
>dev.whoi.edu/thredds/wcs/bathy/gom03_v10?request=GetCoverage&service=WCS&versi
>on=1.0.0&format=GeoTIFF&coverage=topo&bbox=-70.8,41.10,-70.0,41.70"
>
>-Rich
>
>On Fri, Oct 2, 2015 at 3:42 AM, Wright, Simon M. <smw@xxxxxxxxx> wrote:
>> Dear All
>>
>>
>>
>> Can anyone help me with trying to get a WCS 1.0.0 GetCoverage request
>> to work with THREDDS?
>>
>>
>>
>> I'm using THREDDS 4.6.3 and get expected XML responses when I attempt
>> WCS GetCapabilities and DescribeCoverage requests. However, when I
>> attempt a GetCoverage request, with format equal to GeoTIFF or
>> NetCDF3, I get a "This web page is not available ERR_INVALID_RESPONSE"
>> error and when I show the details I'm told that "The web page at...
>> ...might be temporarily down or it may have moved permenantly to a new web
>address."
>>
>>
>>
>> I tried this initially with gridded data in a British National Grid
>> projection and the GetCoverage request fails. I therefore created a
>> dummy netCDF file with a latitude longitude projection and have
>> configured a THREDDS instance in a VM on my local machine to test but
>> I am still getting the same error - the GetCapabilities and
>> DescribeCoverage requests work and the GetCoverage request fails.
>>
>>
>>
>> The form of the WCS requests I'm attempting are as follows:
>>
>> http://localhost:8080/thredds/wcs/smwtestwcs/chess_tas_196101_modified
>> .nc?service=WCS&version=1.0.0&request=GetCapabilities
>>
>> http://localhost:8080/thredds/wcs/smwtestwcs/chess_tas_196101_modified
>> .nc?service=WCS&version=1.0.0&request=DescribeCoverage&coverage=tas
>>
>> http://localhost:8080/thredds/wcs/smwtestwcs/chess_tas_196101_modified
>> .nc?service=WCS&version=1.0.0&request=GetCoverage=tas&time=1961-01-31T
>> 00:00:00Z&format=GeoTIFF
>>
>> http://localhost:8080/thredds/wcs/smwtestwcs/chess_tas_196101_modified
>> .nc?service=WCS&version=1.0.0&request=GetCoverage=tas&time=1961-01-31T
>> 00:00:00Z&format=NetCDF3
>>
>>
>>
>> I have used ToolsUI 4.6 to check that the dummy netCDF file is OK and
>> I can successfully display the gridded data in a netCDF file using the
>> FeatureTypes | Grid tab. I can also display the dummy netCDF file in
>> the
>> Godiva2 viewer in the VM THREDDS instance.
>>
>>
>>
>> The metadata header of the dummy netCDF file is as follows:
>>
>>
>>
>> netcdf C:/smw/Workspace/THREDDS_WCS/Data02/dummy.nc {
>>
>> dimensions:
>>
>> latitude = 6;
>>
>> longitude = 12;
>>
>> variables:
>>
>> float latitude(latitude=6);
>>
>> :_CoordinateAxisType = "Lat";
>>
>> :units = "degrees_north";
>>
>>
>>
>> int crs;
>>
>> :grid_mapping_name = "latitude_longitude";
>>
>> :longitude_of_prime_meridian = 0.0; // double
>>
>> :semi_major_axis = 6378137.0; // double
>>
>> :inverse_flattening = 298.257225363; // double
>>
>> :_CoordinateTransformType = "Projection";
>>
>> :_CoordinateAxes = "x y";
>>
>>
>>
>> float longitude(longitude=12);
>>
>> :_CoordinateAxisType = "Lon";
>>
>> :units = "degrees_east";
>>
>>
>>
>> float pressure(latitude=6, longitude=12);
>>
>> :_CoordinateAxes = "x y";
>>
>> :coordinates = "y x";
>>
>> :long_name = "Pressure";
>>
>> :units = "hPa";
>>
>> :grid_mapping = "crs";
>>
>>
>>
>> float temperature(latitude=6, longitude=12);
>>
>> :_CoordinateAxes = "x y";
>>
>> :coordinates = "y x";
>>
>> :long_name = "Temperature";
>>
>> :units = "celsius";
>>
>> :grid_mapping = "crs";
>>
>>
>>
>> // global attributes:
>>
>> :cdm_data_type = "GRID";
>>
>> :Conventions = "CF-1.0";
>>
>> :featureType = "GRID";
>>
>> }
>>
>>
>>
>> The netCDF file in the British National Grid can also be displayed in
>> ToolsUI 4.6 and Godiva2 viewers.
>>
>>
>>
>> Can anyone shed any light on what I might be doing wrong and why I
>> can't get a GetCoverage WVS request to work?
>>
>>
>>
>>
>>
>>
>>
>> Many thanks, best wishes, Simon.
>>
>>
>>
>>
>>
>> ________________________________
>> This message (and any attachments) is for the recipient only. NERC is
>> subject to the Freedom of Information Act 2000 and the contents of
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>
>
>
>--
>Dr. Richard P. Signell (508) 457-2229
>USGS, 384 Woods Hole Rd.
>Woods Hole, MA 02543-1598
________________________________
This message (and any attachments) is for the recipient only. NERC is subject
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reply you make may be disclosed by NERC unless it is exempt from release under
the Act. Any material supplied to NERC may be stored in an electronic records
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