Make A Graph

Dataset Title:	Operational Hydrodynamic Prediction System (OHPS) : River Current \| Système de simulation hydrodynamique opérationnelle (SHOP) : Courant fluvial
Institution:	Environment and Climate Change Canada (Dataset ID: ecccShopNautilo)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Data Access Form \| Files

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Graph Type:
X Axis:
Y Axis:
Color:

Dimensions

Start

Stop

time (UTC)

specify just 1 value →

latitude (degrees_north)

longitude (degrees_east)

Graph Settings
Color Bar:	Continuity:	Scale:
Minimum:	Maximum:	N Sections:
Draw land mask:
Y Axis Minimum:	Maximum:

(Please be patient. It may take a while to get the data.)

Optional:
Then set the File Type: (File Type information)
and

or view the URL:
(Documentation / Bypass this form

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Click on the map to specify a new center point.

Zoom:

[The graph you specified. Please be patient.]

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 {
    UInt32 _ChunkSizes 49;
    String _CoordinateAxisType "Time";
    Float64 actual_range 1.786968e+9, 1.7871408e+9;
    String axis "T";
    String coverage_content_type "coordinate";
    String ioos_category "Time";
    String long_name "Time";
    String standard_name "time";
    String standard_name_identifier "https://vocab.nerc.ac.uk/collection/P07/current/CFSN0115/";
    String time_origin "01-JAN-1970 00:00:00";
    String units "seconds since 1970-01-01T00:00:00Z";
  }
  latitude {
    String _CoordinateAxisType "Lat";
    Float64 actual_range 45.25651135537644, 47.54866736939348;
    String axis "Y";
    String description "Latitude coordinates in decimal degree (degrees north)";
    String ioos_category "Location";
    String long_name "Latitude";
    String standard_name "latitude";
    String standard_name_identifier "https://vocab.nerc.ac.uk/collection/P07/current/CFSN0600/";
    String units "degrees_north";
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float64 actual_range -74.47075597623737, -70.00782493283515;
    String axis "X";
    String description "Longitude coordinates in decimal degree (degrees east)";
    String ioos_category "Location";
    String long_name "Longitude";
    String standard_name "longitude";
    String standard_name_identifier "https://vocab.nerc.ac.uk/collection/P07/current/CFSN0554/";
    String units "degrees_east";
  }
  x_velocity {
    Float64 colorBarMaximum 1.0;
    Float64 colorBarMinimum -1.0;
    String colorBarPalette "KT_curl";
    String standard_name_identifier "https://vocab.nerc.ac.uk/collection/P07/current/CFSN0336/";
  }
  y_velocity {
    Float64 colorBarMaximum 1.0;
    Float64 colorBarMinimum -1.0;
    String colorBarPalette "KT_curl";
    String standard_name_identifier "https://vocab.nerc.ac.uk/collection/P07/current/CFSN0337/";
  }
  magnitude {
    Float32 _FillValue NaN;
    Float64 colorBarMaximum 2.5;
    Float64 colorBarMinimum 0.0;
    String colorBarPalette "KT_curl";
    String comment "Computed by SLGO from current velocities x and y";
    String description "Speed component of the sea water velocity";
    String ioos_category "Currents";
    String long_name "Magnitude of seawater velocity";
    String short_name "magnitude";
    String standard_name "sea_water_speed";
    String standard_name_identifier "https://vocab.nerc.ac.uk/collection/P07/current/CFSN0334/";
    String units "m s-1";
  }
  direction {
    Float32 _FillValue NaN;
    Float64 colorBarMaximum 360.0;
    Float64 colorBarMinimum 0.0;
    String colorBarPalette "KT_balance";
    String comment "Computed by SLGO from current velocities x and y";
    String description "Direction component of the sea water velocity. Measurements are positive clockwise from north.";
    String ioos_category "Currents";
    String long_name "Direction of seawater velocity";
    String short_name "direction";
    String standard_name "sea_water_velocity_to_direction";
    String standard_name_identifier "https://vocab.nerc.ac.uk/collection/P07/current/5D4D7YMF/";
    String units "degree";
  }
  NC_GLOBAL {
    String cdm_data_type "Grid";
    String Conventions "CF-1.12, COARDS ACDD-1.3";
    String creator_name "Environment and Climate Change Canada";
    String creator_url "https://eccc-msc.github.io/open-data/msc-data/nwp_ohps/readme_ohps_en/";
    String data_source "Meteorological Service of Canada: Operational Hydrodynamic Prediction System (OHPS)";
    String dataset_status "OnGoing";
    Float64 Easternmost_Easting -70.00782493283515;
    Float64 geospatial_lat_max 47.54866736939348;
    Float64 geospatial_lat_min 45.25651135537644;
    Float64 geospatial_lat_resolution 8.492612130481803e-4;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max -70.00782493283515;
    Float64 geospatial_lon_min -74.47075597623737;
    Float64 geospatial_lon_resolution 0.0012400475252576332;
    String geospatial_lon_units "degrees_east";
    String grid_mapping_epsg_code "EPSG:4326";
    String grid_mapping_epsg_code_url "https://epsg.io/4326";
    String grid_mapping_geographic_crs_name "WGS 84";
    String grid_mapping_inverse_flattening "298.2572236";
    String grid_mapping_name "latitude_longitude";
    String grid_mapping_prime_meridian_name "Greenwich";
    String grid_mapping_semi_major_axis "6378137";
    String history 
"Files created from the combinaison of georeferenced .nc files interpolate on a regular grid by SLGO on 2025-08-12T14:24:24Z
2026-08-18T00:41:25Z (local files)
2026-08-18T00:41:25Z http://erddap.cioos.ca/griddap/ecccShopNautilo.das";
    String infoUrl "https://eccc-msc.github.io/open-data/msc-data/nwp_ohps/readme_ohps_en/";
    String institution "Environment and Climate Change Canada";
    String institution_fr "Environnement et Changement Climatique Canada";
    String keywords "surface currents";
    String keywords_fr "courants de surface";
    String keywords_vocabulary "GCMD Science Keywords";
    String license "Environment and Climate Change Canada Data Servers End-use Licence";
    String licenseUrl "https://eccc-msc.github.io/open-data/licence/readme_en/";
    String marine_region "St. Lawrence River";
    String marine_region_identifier "http://marineregions.org/mrgid/23551";
    Float64 Northernmost_Northing 47.54866736939348;
    String platform "unknown";
    String platform_vocabulary "https://vocab.nerc.ac.uk/collection/L06/current/";
    String publisher_email "info@ogsl.ca";
    String publisher_name "St. Lawrence Global Observatory";
    String publisher_name_fr "Observatoire global du Saint-Laurent";
    String publisherID "https://ror.org/03wfagk22";
    String resolution "100 m";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing 45.25651135537644;
    String standard_name_vocabulary "CF Standard Name Table v86";
    String summary "OHPS data produced by Environment and Climate Change Canada.";
    String summary_fr "Données du modèle SHOP produites par Environnement et Changement Climatique Canada.";
    String testOutOfDate "now+1day";
    String time_coverage_end "2026-08-19T12:00:00Z";
    String time_coverage_start "2026-08-17T12:00:00Z";
    String title "Operational Hydrodynamic Prediction System (OHPS) : River Current | Système de simulation hydrodynamique opérationnelle (SHOP) : Courant fluvial";
    Float64 Westernmost_Easting -74.47075597623737;
  }
}

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.