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Dataset Title:	Near Real Time Surface Ocean Total Velocity by HFR-Skagerrak-Total
Institution:	Norwegian Meteorological Institute (Dataset ID: EUHFR_NRTcurrent_HFR-Skagerrak-Total)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Data Access Form \| Files

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Graph Type:
X Axis:
Y Axis:
Color:

Dimensions

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time (UTC)

specify just 1 value →

depth (m)

specify just 1 value →

latitude (degrees_north)

longitude (degrees_east)

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Things You Can Do With Your Graphs

Well, you can do anything you want with your graphs, of course. But some things you might not have considered are:

Web page authors can embed a graph of the latest data in a web page using HTML <img> tags.
Anyone can use ERDDAPs Slide Sorter to build a personal web page that displays graphs with the latest data (or other images or HTML content), each in its own, draggable slide.

The Dataset Attribute Structure (.das) for this Dataset

Attributes {
  time {
    String _CoordinateAxisType "Time";
    Float64 actual_range 1.6003404e+9, 1.7595432e+9;
    String ancillary_variables "TIME_QC";
    String axis "T";
    String calendar "standard";
    String ioos_category "Time";
    String long_name "Time";
    String sdn_P02_urn "SDN:P02::AYMD";
    String sdn_parameter_name "Elapsed time (since 1950-01-01T00:00:00Z)";
    String sdn_parameter_urn "SDN:P01::ELTJLD01";
    String sdn_uom_name "Days";
    String sdn_uom_urn "SDN:P06::UTAA";
    String standard_name "time";
    String time_origin "01-JAN-1970 00:00:00";
    String units "seconds since 1970-01-01T00:00:00Z";
  }
  depth {
    String _CoordinateAxisType "Height";
    String _CoordinateZisPositive "down";
    Float32 actual_range 0.0, 0.0;
    String ancillary_variables "DEPTH_QC";
    String axis "Z";
    String ioos_category "Location";
    String long_name "Depth";
    String positive "down";
    String references "sea_level";
    String sdn_P02_urn "SDN:P02::AHGT";
    String sdn_parameter_name "Depth below surface of the water body";
    String sdn_parameter_urn "SDN:P01::ADEPZZ01";
    String sdn_uom_name "Metres";
    String sdn_uom_urn "SDN:P06::ULAA";
    String standard_name "depth";
    String units "m";
  }
  latitude {
    String _CoordinateAxisType "Lat";
    Float32 actual_range 57.01102, 59.48898;
    String ancillary_variables "POSITION_QC";
    String axis "Y";
    String ioos_category "Location";
    String long_name "Latitude";
    String sdn_P02_urn "SDN:P02::ALAT";
    String sdn_parameter_name "Latitude north";
    String sdn_parameter_urn "SDN:P01::ALATZZ01";
    String sdn_uom_name "Degrees north";
    String sdn_uom_urn "SDN:P06::DEGN";
    String standard_name "latitude";
    String units "degrees_north";
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float32 actual_range 7.50205, 11.99795;
    String ancillary_variables "POSITION_QC";
    String axis "X";
    String ioos_category "Location";
    String long_name "Longitude";
    String sdn_P02_urn "SDN:P02::ALAT";
    String sdn_parameter_name "Longitude east";
    String sdn_parameter_urn "SDN:P01::ALONZZ01";
    String sdn_uom_name "Degrees east";
    String sdn_uom_urn "SDN:P06::DEGE";
    String standard_name "longitude";
    String units "degrees_east";
  }
  GDOP {
    Float64 _FillValue -32.767;
    String ancillary_variables "QCflag GDOP_QC";
    Float64 colorBarMaximum 0.1;
    Float64 colorBarMinimum 0.0;
    String comment "The Geometric Dilution of Precision (GDOP) is the coefficient of the uncertainty, which relates the uncertainties in radial and velocity vectors. The GDOP is a unit-less coefficient, which characterizes the effect that radar station geometry has on the measurement and position determination errors. A low GDOP corresponds to an optimal geometric configuration of radar stations, and results in accurate surface current data. Essentially, GDOP is a quantitative way to relate the radial and velocity vector uncertainties. Setting a threshold on GDOP for total combination avoids the combination of radials with an intersection angle below a certain value. GDOP is a useful metric for filtering errant velocities due to poor geometry.";
    String long_name "Geometrical dilution of precision";
    String sdn_parameter_name "Dilution of precision";
    String sdn_parameter_urn "SDN:S06::S0600236";
    String sdn_uom_name "Dimensionless";
    String sdn_uom_urn "SDN:P06::UUUU";
    String units "1";
    Float64 valid_max 20.0;
    Float64 valid_min -20.0;
  }
  DDNS_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "Data Density Threshold QC Test - Test applies to each vector. Threshold=[minimum number of contributing radial velocities=3]";
    String conventions "EuroGOOS European HFR Node";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String long_name "Data density threshold quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  CSPD_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "Velocity Threshold QC Test - Test applies to each vector. Threshold=[maximum velocity=1.2 (m/s)]";
    String conventions "EuroGOOS European HFR Node";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String long_name "Velocity threshold quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  VART_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "Variance Threshold QC Test not applicable to Direction Finding systems. Temporal Derivative QC Test - Test applies to each vector. Threshold=[velocity difference threshold=1.2 (m/s)]";
    String conventions "EuroGOOS European HFR Node";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String long_name "Variance threshold quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  GDOP_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "GDOP Threshold QC Test - Test applies to each vector. Threshold=[GDOP threshold=2.0]";
    String conventions "EuroGOOS European HFR Node";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String long_name "GDOP threshold quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  QCflag {
    Byte _FillValue -127;
    String _Unsigned "false";
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "Overall QC Flag - Test applies to each vector. Test checks if all QC tests are passed.";
    String conventions "EuroGOOS European HFR Node";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String long_name "Overall quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  EWCT {
    Float64 _FillValue -32.767;
    String ancillary_variables "QCflag VART_QC CSPD_QC DDNS_QC GDOP_QC";
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String long_name "Surface eastward sea water velocity";
    String sdn_P02_urn "SDN:P02::RFVL";
    String sdn_parameter_name "Eastward velocity of water current in the water body";
    String sdn_parameter_urn "SDN:P01::LCEWZZ01";
    String sdn_uom_name "Metres per second";
    String sdn_uom_urn "SDN:P06::UVAA";
    String standard_name "surface_eastward_sea_water_velocity";
    String units "m s-1";
    Float64 valid_max 10.0;
    Float64 valid_min -10.0;
  }
  NSCT {
    Float64 _FillValue -32.767;
    String ancillary_variables "QCflag VART_QC CSPD_QC DDNS_QC GDOP_QC";
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String long_name "Surface northward sea water velocity";
    String sdn_P02_urn "SDN:P02::RFVL";
    String sdn_parameter_name "Northward current velocity in the water body";
    String sdn_parameter_urn "SDN:P01::LCNSZZ01";
    String sdn_uom_name "Metres per second";
    String sdn_uom_urn "SDN:P06::UVAA";
    String standard_name "surface_northward_sea_water_velocity";
    String units "m s-1";
    Float64 valid_max 10.0;
    Float64 valid_min -10.0;
  }
  EWCS {
    Float64 _FillValue -32.767;
    String ancillary_variables "QCflag VART_QC";
    Float64 colorBarMaximum 0.1;
    Float64 colorBarMinimum 0.0;
    String long_name "Standard deviation of surface eastward sea water velocity";
    String sdn_P02_urn "SDN:P02::RFVL";
    String sdn_parameter_name "Eastward current velocity standard deviation in the water body";
    String sdn_parameter_urn "SDN:P01::SDEWZZZZ";
    String sdn_uom_name "Metres per second";
    String sdn_uom_urn "SDN:P06::UVAA";
    String units "m s-1";
    Float64 valid_max 10.0;
    Float64 valid_min -10.0;
  }
  NSCS {
    Float64 _FillValue -32.767;
    String ancillary_variables "QCflag VART_QC";
    Float64 colorBarMaximum 0.1;
    Float64 colorBarMinimum 0.0;
    String long_name "Standard deviation of surface northward sea water velocity";
    String sdn_P02_urn "SDN:P02::RFVL";
    String sdn_parameter_name "Northward current velocity standard deviation in the water body";
    String sdn_parameter_urn "SDN:P01::SDNSZZZZ";
    String sdn_uom_name "Metres per second";
    String sdn_uom_urn "SDN:P06::UVAA";
    String units "m s-1";
    Float64 valid_max 10.0;
    Float64 valid_min -10.0;
  }
  CCOV {
    Float64 _FillValue -2147.483647;
    String ancillary_variables "QCflag";
    Float64 colorBarMaximum 50.0;
    Float64 colorBarMinimum 0.0;
    String long_name "Covariance of surface sea water velocity";
    String sdn_uom_name "Square metres per second squared";
    String sdn_uom_urn "SDN:P06::SQM2";
    String units "m2 s-2";
    Float64 valid_max 10.0;
    Float64 valid_min -10.0;
  }
  POSITION_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "Quality flagging for position coordinates.";
    String conventions "EuroGOOS European HFR Node";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String long_name "Position quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  NC_GLOBAL {
    String acknowledgement "HFR-Skagerrak Radar Network has been designed, implemented and managed through the efforts of the Norwegian Meteorological Institute.";
    String area "Skagerrak";
    String calibration_link "JOMF: terjeb@met.no, TORU: terjeb@met.no";
    String calibration_type "JOMF: APM, TORU: APM";
    String cdm_data_type "Grid";
    String citation "These data were collected and made freely available by the EuroGOOS European HFR Node. Data collected and processed by the Norwegian Meteorological Institute.";
    String comment "Total velocities are derived using least square fit that maps radial velocities measured from individual sites onto a cartesian grid. The final product is a map of the horizontal components of the ocean currents on a regular grid in the area of overlap of two or more radar stations.";
    String contributor_email "terjeb@met.no; martinai@met.no";
    String contributor_name "Terje Borge; Martina Idzanovic";
    String contributor_role "Site manager; Administrative contact";
    String Conventions "CF-1.11, EuroGOOS European HFR Node, COARDS, ACDD-1.3";
    String creator_email "lorenzo.corgnati@sp.ismar.cnr.it";
    String creator_name "Lorenzo Corgnati";
    String creator_type "person";
    String creator_url "https://www.hfrnode.eu/";
    String data_assembly_center "European HFR Node";
    String data_character_set "utf8";
    String data_language "eng";
    String data_mode "R";
    String data_type "HF radar total current data";
    String date_created "2025-10-05T12:07:36Z";
    String date_modified "2025-10-05T12:07:36Z";
    String distribution_statement "These data are public and free of charge. User assumes all risk for use of data. User must display citation in any publication or product using data. User must contact PI prior to any commercial use of data.";
    String doa_estimation_method "JOMF: Direction Finding, TORU: Direction Finding";
    Float64 Easternmost_Easting 11.99795;
    String format_version "v3";
    Float64 geospatial_lat_max 59.48898;
    Float64 geospatial_lat_min 57.01102;
    Float64 geospatial_lat_resolution 0.02693434782608691;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 11.99795;
    Float64 geospatial_lon_min 7.50205;
    Float64 geospatial_lon_resolution 0.05108977272727273;
    String geospatial_lon_units "degrees_east";
    String history 
"Data collected at 2025-10-04T02:00:00Z. netCDF file created at 2025-10-05T12:07:36Z by the European HFR Node.
2026-02-21T20:57:26Z (local files)
2026-02-21T20:57:26Z http://erddap.emodnet-physics.eu/griddap/EUHFR_NRTcurrent_HFR-Skagerrak-Total.das";
    String id "HFR-Skagerrak-Total_2025-10-04T02:00:00Z";
    String infoUrl "https://www.hfrnode.eu/";
    String institution "Norwegian Meteorological Institute";
    String institution_edmo_code "1212";
    String institution_references "http://www.met.no";
    String keywords "CCOV, circulation, covariance, CSPD_QC, currents, data, DDNS_QC, density, depth, deviation, dilution, earth, Earth Science > Oceans > Ocean Circulation > Ocean Currents, eastward, EWCS, EWCT, flag, frequency, gdop, GDOP_QC, geometrical, HF, hf radar, hfr, hfr-skagerrak-total, hfradar, high, institute, latitude, longitude, meteorological, near, near real time, northward, norwegian, NSCS, NSCT, ocean, ocean currents, oceans, overall, position, POSITION_QC, precision, QCflag, quality, radar, real, science, scr-hf, sea, seawater, skagerrak, standard, surface, surface water, surface_eastward_sea_water_velocity, surface_northward_sea_water_velocity, threshold, time, total, variance, VART_QC, velocity, water";
    String keywords_vocabulary "GCMD Science Keywords";
    String last_calibration_date "JOMF: 2020-06-12T00:00:00Z, TORU: 2020-07-10T00:00:00Z";
    String license "HF radar sea surface current velocity dataset by the Norwegian Meteorological Institute is licensed under a Creative Commons Attribution 4.0 International License. You should have received a copy of the license along with this work. If not, see https://creativecommons.org/licenses/by/4.0/.";
    String manufacturer "JOMF: Codar, TORU: Codar";
    String metadata_character_set "utf8";
    String metadata_contact "lorenzo.corgnati@sp.ismar.cnr.it";
    String metadata_date_stamp "2025-10-05T12:07:36Z";
    String metadata_language "eng";
    String naming_authority "eu.hfrnode";
    String netcdf_format "NETCDF4_CLASSIC";
    String netcdf_version "4.9.3";
    String network "MetNo HFR-Skagerrak";
    Float64 Northernmost_Northing 59.48898;
    String platform_code "HFR-Skagerrak-Total";
    String processing_level "3B";
    String publisher_email "euhfrnode@azti.es";
    String publisher_name "European HFR Node";
    String publisher_type "institution";
    String publisher_url "https://www.hfrnode.eu/";
    String qc_manual "Recommendation Report 2 on improved common procedures for HFR QC analysis: https://dx.doi.org/10.25607/OBP-944";
    String reference_system "EPSG:4326";
    String references "Recommendation Report 2 on improved common procedures for HFR QC analysis: https://dx.doi.org/10.25607/OBP-944";
    String sensor_model "JOMF: Codar, TORU: Codar";
    String site_code "HFR-Skagerrak";
    String software_name "EU_HFR_NODE_NRTprocessor";
    String software_version "v3";
    String source "coastal structure";
    String source_platform_category_code "17";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing 57.01102;
    String standard_name_vocabulary "CF Standard Name Table v70";
    String summary "The data set consists of maps of total velocity of the surface current in the Skagerrak Strait averaged over a time interval of 1 hour around the cardinal hour. Surface ocean velocities estimated by High Frequency (HF) Radar are representative of the upper 0.3-2.5 meters of the ocean.";
    String testOutOfDate "now-1day";
    String time_coverage_duration "PT1H";
    String time_coverage_end "2025-10-04T02:00:00Z";
    String time_coverage_resolution "PT1H";
    String time_coverage_start "2020-09-17T11:00:00Z";
    String title "Near Real Time Surface Ocean Total Velocity by HFR-Skagerrak-Total";
    String topic_category "oceans";
    String update_interval "void";
    Float64 Westernmost_Easting 7.50205;
  }
}

Using griddap to Request Data and Graphs from Gridded Datasets

griddap lets you request a data subset, graph, or map from a gridded dataset (for example, sea surface temperature data from a satellite), via a specially formed URL. griddap uses the OPeNDAP (external link)

Data Access Protocol (DAP) (external link)

and its projection constraints (external link)

The URL specifies what you want: the dataset, a description of the graph or the subset of the data, and the file type for the response.

(easy) You can get data by using the dataset's Data Access Form. It makes the URL for you.
(easy) You can make a graph or map by using the dataset's Make A Graph form. It makes the URL for you.
(not hard) You can bypass the forms and get the data or make a graph or map by generating the URL by hand or with a computer program or script.

griddap request URLs must be in the form
https://coastwatch.pfeg.noaa.gov/erddap/griddap/datasetID.fileType{?query}
For example,
https://coastwatch.pfeg.noaa.gov/erddap/griddap/jplMURSST41.htmlTable?analysed_sst[(2002-06-01T09:00:00Z)][(-89.99):1000:(89.99)][(-179.99):1000:(180.0)]
Thus, the query is often a data variable name (e.g., analysed_sst), followed by [(start):stride:(stop)] (or a shorter variation of that) for each of the variable's dimensions (for example, [time][latitude][longitude]).

For details, see the griddap Documentation.