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Dataset Title:	Surface Currents (Totals), HF Radar, Halifax, CA East Coast, NRT, 2015- present, Hourly
Institution:	Ocean Frontier Institute (Dataset ID: codar_totals_2015)
Range:	longitude = -64.94239 to -61.668545°E, latitude = 42.561676 to 44.694332°N, time = 2015-11-24T18:00:00.000Z to 2026-04-03T13:00:00.000Z
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Subset \| Data Access Form \| Files

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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 {
 s {
  time {
    String _CoordinateAxisType "Time";
    Float64 actual_range 1.448388e+9, 1.7752212e+9;
    String axis "T";
    String identifier "timestamp";
    String ioos_category "Time";
    String long_name "Time";
    String standard_name "time";
    String time_origin "01-JAN-1970 00:00:00";
    String time_precision "1970-01-01T00:00:00.000Z";
    String units "seconds since 1970-01-01T00:00:00Z";
  }
  latitude {
    String _CoordinateAxisType "Lat";
    Float64 actual_range 42.5616743, 44.6943339;
    String axis "Y";
    String identifier "latitude";
    String ioos_category "Location";
    String long_name "Latitude";
    String standard_name "latitude";
    String units "degrees_north";
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float64 actual_range -64.9423874, -61.6685462;
    String axis "X";
    String identifier "longitude";
    String ioos_category "Location";
    String long_name "Longitude";
    String standard_name "longitude";
    String units "degrees_east";
  }
  VELU {
    Float64 actual_range -199.428, 199.592;
    String identifier "u_comp";
    String ioos_category "Currents";
    String long_name "Eastward component of surface current (cm/s)";
    String standard_name "surface_eastward_sea_water_velocity";
    String units "cm/s";
    String vocabulary "https://vocab.nerc.ac.uk/collection/P07/current/CFSN0266/";
  }
  VELV {
    Float64 actual_range -199.402, 198.969;
    String identifier "v_comp";
    String ioos_category "Currents";
    String long_name "Northward component of surface current (cm/s)";
    String standard_name "surface_northward_sea_water_velocity";
    String units "cm/s";
    String vocabulary "https://vocab.nerc.ac.uk/collection/P07/current/CFSN0242/";
  }
  VELO {
    Float64 actual_range 0.002, 199.982;
    String identifier "velocity";
    String ioos_category "Currents";
    String long_name "speed";
    String units "cm/s";
  }
  HEAD {
    Float64 actual_range 0.0, 360.0;
    String identifier "direction";
    String ioos_category "Currents";
    String long_name "direction";
    String units "degree";
  }
 }
  NC_GLOBAL {
    String cdm_data_type "Point";
    String comment "The Research Implementation Unit (RIU) of the Ocean Frontier Institute operates long-range 5 MHz CODAR SeaSonde systems on the eastern coast of Nova Scotia to support tsunami detection, wave and wind monitoring, search and rescue, environmental monitoring, marine navigation, and pollution response. Total currents are derived by combining radial observations from multiple CODAR stations.";
    String Conventions "CF-1.12";
    String creator_country "Canada";
    String creator_institution "Ocean Frontier Institute";
    String creator_name "Research Implementation Unit (RIU); Ocean Frontier Institute";
    String creator_type "institution";
    String creator_url "https://www.ofi.ca/";
    Float64 Easternmost_Easting -61.6685462;
    String featureType "Point";
    Float64 geospatial_lat_max 44.6943339;
    Float64 geospatial_lat_min 42.5616743;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max -61.6685462;
    Float64 geospatial_lon_min -64.9423874;
    String geospatial_lon_units "degrees_east";
    String history 
"2026-04-03T17:17:59Z (local files)
2026-04-03T17:17:59Z http://data.ceotr.ca/tabledap/codar_totals_2015.das";
    String id "codar_totals_2015";
    String infoUrl "https://www.ofi.ca";
    String institution "Ocean Frontier Institute";
    String keywords "CODAR, HF radar, Nova Scotia, ocean monitoring, pollution response, Scotian Shelf, search and rescue, SeaSonde, surface currents, totals, tsunami detection, vector currents";
    String license "This data may be redistributed and used without restriction.";
    Float64 Northernmost_Northing 44.6943339;
    String platform "surface_current_radar";
    String references "CODAR systems are coastal land-based high-frequency radar sensors that estimate ocean surface currents from Bragg scattering and Doppler shift observations. The Research Implementation Unit (RIU) of the Ocean Frontier Institute manages the eastern Nova Scotia CODAR network, and total vectors are obtained by combining radial observations from at least two stations.";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing 42.5616743;
    String standard_name_vocabulary "CF Standard Name Table v79";
    String subsetVariables "latitude, longitude";
    String summary "CODAR total current measurements combine radial observations from multiple stations to produce vector estimates of ocean surface currents across the Halifax, Nova Scotia coastal domain. Data include current velocity, direction, uncertainty, and contributing-site information.";
    String time_coverage_end "2026-04-03T13:00:00.000Z";
    String time_coverage_start "2015-11-24T18:00:00.000Z";
    String title "Surface Currents (Totals), HF Radar, Halifax, CA East Coast, NRT, 2015-present, Hourly";
    Float64 Westernmost_Easting -64.9423874;
  }
}

Using tabledap to Request Data and Graphs from Tabular Datasets

tabledap lets you request a data subset, a graph, or a map from a tabular dataset (for example, buoy data), via a specially formed URL. tabledap uses the OPeNDAP (external link)

Data Access Protocol (DAP) (external link)

and its selection 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 or Subset form. They make 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.

Tabledap request URLs must be in the form
https://coastwatch.pfeg.noaa.gov/erddap/tabledap/datasetID.fileType{?query}
For example,
https://coastwatch.pfeg.noaa.gov/erddap/tabledap/pmelTaoDySst.htmlTable?longitude,latitude,time,station,wmo_platform_code,T_25&time>=2015-05-23T12:00:00Z&time<=2015-05-31T12:00:00Z
Thus, the query is often a comma-separated list of desired variable names, followed by a collection of constraints (e.g., variable<value), each preceded by '&' (which is interpreted as "AND").

For details, see the tabledap Documentation.

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