Make A Graph

Dataset Title:	Primary Productivity, VIIRS NOAA20, Science Quality, Global, 4km, 2017- present, (Monthly Composite)
Institution:	NOAA CoastWatch West Coast Node (Dataset ID: productivity_viirs_noaa20_monthly)
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 {
    String _CoordinateAxisType "Time";
    Float64 actual_range 1.518768e+9, 1.7500572e+9;
    String axis "T";
    String calendar "Gregorian";
    String coverage_content_type "coordinate";
    String ioos_category "Time";
    String long_name "Centered Time";
    String standard_name "time";
    String time_origin "01-JAN-1970 00:00:00";
    String units "seconds since 1970-01-01T00:00:00Z";
  }
  latitude {
    String _CoordinateAxisType "Lat";
    Float32 actual_range -89.97917, 89.97916;
    String axis "Y";
    String coverage_content_type "coordinate";
    String ioos_category "Location";
    String long_name "Latitude";
    String standard_name "latitude";
    String units "degrees_north";
    Float32 valid_max 90.0;
    Float32 valid_min -90.0;
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float32 actual_range -179.9792, 179.9792;
    String axis "X";
    String coverage_content_type "coordinate";
    String ioos_category "Location";
    String long_name "Longitude";
    String standard_name "longitude";
    String units "degrees_east";
    Float32 valid_max 180.0;
    Float32 valid_min -180.0;
  }
  productivity {
    Float32 _FillValue -999.0;
    String cell_methods "time:mean";
    Float64 colorBarMaximum 2000.0;
    Float64 colorBarMinimum 20.0;
    String colorBarScale "Log";
    String coverage_content_type "physicalMeasurement";
    String ioos_category "Productivity";
    String long_name "Net Primary Productivity Of Carbon";
    Float32 missing_value -999.0;
    String standard_name "net_primary_productivity_of_carbon";
    String units "mg C m-2 day-1";
  }
  NC_GLOBAL {
    String acknowledgement "This project was supported by the NOAA Office of Satellite Ground Services to CoastWatch West Coast Node via NOAA SWFSC.";
    String cdm_data_type "Grid";
    String Conventions "CF-1.10, ACDD-1.3, COARDS";
    String creator_email "coastwatch.info@noaa.gov";
    String creator_name "NOAA/STAR/NESDIS/CoastWatch/WestCoastNode";
    String creator_url "https://coastwatch.pfeg.noaa.gov/";
    String date_created "2025-07-07T13:21:41Z";
    Float64 Easternmost_Easting 179.9792;
    Float32 easternmost_longitude 180.0;
    Float64 geospatial_lat_max 89.97916;
    Float64 geospatial_lat_min -89.97917;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 179.9792;
    Float64 geospatial_lon_min -179.9792;
    String geospatial_lon_units "degrees_east";
    String history 
"Chlorophyll a, PAR, and SST satellite data from VIIRS NOAA-20 were applied to the equation of Behrenfeld and Falkowski, 1997 to make daily composite files. The monthly file are means of the daily files.
2026-01-23T18:16:24Z (local files)
2026-01-23T18:16:24Z https://coastwatch.pfeg.noaa.gov/griddap/productivity_viirs_noaa20_monthly.das";
    String id "productivity_noaa20_mday";
    String infoUrl "coastwatch-wcn.github.io/primary-productivity";
    String institution "NOAA CoastWatch West Coast Node";
    String instrument "VIIRS";
    String keywords "2017-present, 2018-present, 4km, active, air, available, biosphere, carbon, chemistry, chla, chlor_a, chlorophyll, chlorophyll-a, coast, coastwatch, color, composite, concentration, data, day, downwelling, dynamics, earth, Earth Science > Biosphere > Ecological Dynamics > Ecosystem Functions > Primary Production, Earth Science > Biosphere > Vegetation > Carbon, Earth Science > Biosphere > Vegetation > Photosynthetically Active Radiation, Earth Science > Oceans > Ocean Chemistry > Carbon, Earth Science > Oceans > Ocean Chemistry > Chlorophyll, Earth Science > Oceans > Ocean Chemistry > Pigments > Chlorophyll, Earth Science > Oceans > Ocean Optics > Photosynthetically Available Radiation, Earth Science > Oceans > Ocean Temperature > Sea Surface Temperature, ecological, ecosystem, flux, functions, global, image, imager, imager/radiometer, imaging, infrared, latitude, longitude, mapped, mass, mass_concentration_of_chlorophyll_in_sea_water, net, net_primary_productivity_of_carbon, noaa, noaa-20, noaa20, node, ocean, ocean color, oceans, optics, par, photon, photosynthetic, photosynthetically, pigments, present, primary, production, productivity, quality, radiation, radiometer, science, science quality, sea, sea_surface_temperature, seawater, smi, sst, standard, suite, surface, surface_downwelling_photosynthetic_photon_flux_in_air, temperature, time, vegetation, viirs, visible, water, west, west coast node";
    String keywords_vocabulary "NASA Global Change Master Directory (GCMD) Science Keywords";
    String license 
"The data may be used and redistributed for free but is not intended
for legal use, since it may contain inaccuracies. Neither the data
Contributor, ERD, NOAA, nor the United States Government, nor any
of their employees or contractors, makes any warranty, express or
implied, including warranties of merchantability and fitness for a
particular purpose, or assumes any legal liability for the accuracy,
completeness, or usefulness, of this information.";
    String map_projection "Equidistant Cylindrical";
    String naming_authority "griddap/erddap/gov.noaa.pfeg.coastwatch";
    Float32 northernmost_latitude 90.0;
    Float64 Northernmost_Northing 89.97916;
    String platform "NOAA-20";
    String processing_level "L3 Mapped";
    String product_name "VIIRS NOAA-20 Primary Productivity";
    String project "CoastWatch Primary Productivity Project";
    String publisher_email "erd.data at noaa.gov";
    String publisher_name "NOAA/NMFS/SWFSC/ITDS/ERD, NOAA/NESDIS/STAR/CoastWatch/West Coast";
    String publisher_url "https://coastwatch.pfeg.noaa.gov/";
    String reference "M.J. Behrenfeld and P. G. Falkowski, Photosynthetic rates derived from satellite-based chlorophyll concentration, Limnol. Oceanogr. 42(l), 1997. 1-20";
    String source "satellite observations from VIIRS NOAA-20";
    String sourceUrl "(local files)";
    Float32 southernmost_latitude -90.0;
    Float64 Southernmost_Northing -89.97917;
    String spatialResolution "4.638312 km";
    String standard_name_vocabulary "CF Standard Name Table v36";
    String summary "The VIIRS NOAA-20 Primary Productivity product estimates net carbon fixation by phytoplankton in oceanic waters using the algorithm of Behrenfeld and P. G. Falkowski (1997). Data sources used as in the algorithm are chlorophyll a, SST and PAR values from VIIRS NOAA-20. The chlorophyll a, SST, and PAR data used as inputs to the algorithm are included in the dataset. Data are mapped to a NASA 4km Standard Mapped Image. The monthly data are means of the daily composites";
    Float32 sw_point_latitude -89.97916;
    Float32 sw_point_longitude -179.9792;
    String temporal_range "month";
    String testOutOfDate "now-116days";
    String time_coverage_end "2025-06-16T07:00:00Z";
    String time_coverage_resolution "P1M";
    String time_coverage_start "2018-02-16T08:00:00Z";
    String title "Primary Productivity, VIIRS NOAA20, Science Quality, Global, 4km, 2017-present, (Monthly Composite)";
    Float64 Westernmost_Easting -179.9792;
    Float32 westernmost_longitude -180.0;
  }
}

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.