Make A Graph

Dataset Title:	Chlorophyll, Blended NOAA-SNPP and NOAA-20 VIIRS, Near Real-Time, Global, Level 3, 0.0375°, 2018-present EXPERIMENTAL, Daily
Institution:	NOAA NESDIS STAR (Dataset ID: nesdisVHNnoaaSNPPnoaa20chlaDaily)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Data Access Form

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Graph Type:
X Axis:
Y Axis:
Color:

Dimensions

Start

Stop

time (UTC)

specify just 1 value →

altitude (m)

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:
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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 1.533816e+9, 1.6190064e+9;
    String axis "T";
    String calendar "gregorian";
    String ioos_category "Time";
    String long_name "Time";
    String standard_name "time";
    String time_origin "01-JAN-1970 00:00:00";
    String units "seconds since 1970-01-01T00:00:00Z";
  }
  altitude {
    String _CoordinateAxisType "Height";
    String _CoordinateZisPositive "up";
    Float64 actual_range 0.0, 0.0;
    String axis "Z";
    String ioos_category "Location";
    String long_name "Altitude";
    String positive "up";
    String standard_name "altitude";
    String units "m";
  }
  latitude {
    String _CoordinateAxisType "Lat";
    Float32 actual_range -89.75626, 89.75625;
    String axis "Y";
    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 -179.9812, 179.9813;
    String axis "X";
    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;
  }
  chl_oci {
    Float32 _FillValue -32767.0;
    String C_format "%.4g";
    String cell_methods "time:mean";
    Float64 colorBarMaximum 30.0;
    Float64 colorBarMinimum 0.03;
    String colorBarScale "Log";
    String coverage_content_type "physicalMeasurement";
    String ioos_category "Ocean Color";
    String long_name "Chlorophyll Concentration, OCI Algorithm";
    String references "Hu, C., Lee Z., and Franz, B.A. (2012). Chlorophyll-a algorithms for oligotrophic oceans: A novel approach based on three-band reflectance difference, J. Geophys. Res., 117, C01011, doi:10.1029/2011JC007395.";
    String standard_name "mass_concentration_of_chlorophyll_a_in_sea_water";
    String units "mg m^-3";
    Float32 valid_max 100.0;
    Float32 valid_min 0.001;
  }
  NC_GLOBAL {
    String _lastModified "2021-04-21T15:01:10.000Z";
    String cdm_data_type "Grid";
    String Conventions "CF-1.6, COARDS, ACDD-1.3";
    String creator_email "coastwatch.info@noaa.gov";
    String creator_name "NOAA CoastWatch";
    String creator_type "institution";
    String creator_url "https://coastwatch.noaa.gov";
    String date_created "2021-04-21T15:01:10.000Z";
    Float64 Easternmost_Easting 179.9813;
    Float64 geospatial_lat_max 89.75625;
    Float64 geospatial_lat_min -89.75626;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 179.9813;
    Float64 geospatial_lon_min -179.9812;
    String geospatial_lon_units "degrees_east";
    Float64 geospatial_vertical_max 0.0;
    Float64 geospatial_vertical_min 0.0;
    String geospatial_vertical_positive "up";
    String geospatial_vertical_units "m";
    Float32 grid_mapping_inverse_flattening 298.2572;
    Float32 grid_mapping_longitude_of_prime_meridian 0.0;
    String grid_mapping_name "latitude_longitude";
    Float32 grid_mapping_semi_major_axis 6378137.0;
    String history 
"/data/home004/hgu/docker_v224/bin/l3mapgen par=/data/home004/hgu/docker_v224/bin/../config/l3mapgen_par_chl_oci ifile=/data/home004/hgu/docker_v224/bin/../temp/Config_mixed/infile_iop_2km_G_chl_oci.nc ofile=/data/data369/viirs/L3/2021/04/20/V2021110_D1_NPP-N20_WW00_chl_oci.nc   Wed Apr 21 15:01:17 2021
: /data/home004/hgu/docker_v224/bin/l3cnvtr -s Suomi-NPP,NOAA-20 /data/data369/viirs/L3/2021/04/20/V2021110_D1_NPP-N20_WW00_chl_oci.nc /data/socd6/coastwatch/mixed_viirs/L3/global/chlora/daily/WW00/V2021110_D1_NPP-N20_WW00_chloci.nc
2021-04-23T08:29:50Z https://coastwatch.noaa.gov/thredds/dodsC/CoastWatch/VIIRS/npp-n20/chloci/DailyGlobal/WW00
2021-04-23T08:29:50Z http://coastwatch.pfeg.noaa.gov/griddap/nesdisVHNnoaaSNPPnoaa20chlaDaily.das";
    String id "L3//data/data320/L3bin_global/VIIRSMIX/noaa_msl12_nrt/daily/2021/20210420/2km/infile_iop_2km_G_chl_oci_rhw1184_6401.nc";
    String identifier_product_doi "https://dx.doi.org";
    String identifier_product_doi_authority "https://dx.doi.org";
    String infoUrl "https://coastwatch.noaa.gov/cw/satellite-data-products/ocean-color/near-real-time/viirs.html";
    String institution "NOAA NESDIS STAR";
    String instrument "VIIRS";
    String keywords "algorithm, altitude, chemistry, chl_oci, chlorophyll, color, concentration, data, earth, Earth Science > Oceans > Ocean Chemistry > Chlorophyll, Earth Science > Oceans > Ocean Optics > Ocean Color, image, imager, imager/radiometer, imaging, infrared, L3, latitude, level, level-3, longitude, mapped, mass, mass_concentration_of_chlorophyll_a_in_sea_water, national, npp, ocean, ocean color, oceans, oci, optics, orbiting, partnership, polar, polar-orbiting, radiometer, science, sea, seawater, smi, standard, star, suite, suite/suomi-npp, suomi, time, viirs, viirs-n, viirsn, visible, water, ww00";
    String keywords_vocabulary "GCMD Science Keywords";
    String l2_flag_names "ATMFAIL,LAND,HIGLINT,HILT,HISATZEN,CLOUD,HISOLZEN,NAVWARN,CLDSHDSTL,ALGICE,SEAICE,NAVFAIL,FILTER";
    String license "These data may be redistributed and used without restriction.";
    String map_projection "geographic";
    String measure "Mean";
    String naming_authority "gov.noaa.coastwatch";
    Float64 Northernmost_Northing 89.75625;
    String platform "Suomi-NPP,NOAA-20";
    String processing_control_input_parameters_apply_pal "yes";
    String processing_control_input_parameters_central_meridian "-999";
    String processing_control_input_parameters_deflate "4";
    String processing_control_input_parameters_east "180.0";
    String processing_control_input_parameters_fudge "1.0";
    String processing_control_input_parameters_ifile "/data/home004/hgu/docker_v224/bin/../temp/Config_mixed/infile_iop_2km_G_chl_oci.nc";
    String processing_control_input_parameters_interp "nearest";
    String processing_control_input_parameters_north "89.775";
    String processing_control_input_parameters_ofile "/data/data369/viirs/L3/2021/04/20/V2021110_D1_NPP-N20_WW00_chl_oci.nc";
    String processing_control_input_parameters_oformat "netcdf4";
    String processing_control_input_parameters_oformat2 "png";
    String processing_control_input_parameters_palette_dir "$OCDATAROOT/common/palette";
    String processing_control_input_parameters_par "/data/home004/hgu/docker_v224/bin/../config/l3mapgen_par_chl_oci";
    String processing_control_input_parameters_product "chl_oci";
    String processing_control_input_parameters_product_rgb "rhos_671,rhos_551,rhos_486";
    String processing_control_input_parameters_projection "platecarree";
    String processing_control_input_parameters_quiet "false";
    String processing_control_input_parameters_resolution "0.0375deg";
    String processing_control_input_parameters_scale_type "log";
    String processing_control_input_parameters_south "-89.775";
    String processing_control_input_parameters_threshold "0";
    String processing_control_input_parameters_use_quality "yes";
    String processing_control_input_parameters_use_rgb "no";
    String processing_control_input_parameters_west "-180.0";
    String processing_control_l2_flag_names "ATMFAIL,LAND,HIGLINT,HILT,HISATZEN,CLOUD,HISOLZEN,NAVWARN,CLDSHDSTL,ALGICE,SEAICE,NAVFAIL,FILTER";
    String processing_control_software_name "l3mapgen";
    String processing_control_software_version "1.0.1-r12992";
    String processing_control_source "infile_iop_2km_G_chl_oci.nc";
    String processing_level "L3 Mapped";
    String product_name "V2021110_D1_NPP-N20_WW00_chloci.nc";
    String project "Ocean Color Science Team (NOAA/NESDIS/STAR/OCST)";
    String publisher_email "coastwatch.info@noaa.gov;ncei.info@noaa.gov";
    String publisher_name "NOAA CoastWatch;National Centers for Environmental Information (NCEI)";
    String publisher_type "group";
    String publisher_url "https://coastwatch.noaa.gov;https://www.ncei.noaa.gov/";
    String Satellite 
"Suomi-NPP
NOAA-20";
    String Sensor "VIIRS";
    String sourceUrl "https://coastwatch.noaa.gov/thredds/dodsC/CoastWatch/VIIRS/npp-n20/chloci/DailyGlobal/WW00";
    Float64 Southernmost_Northing -89.75626;
    String spatialResolution "4.17 km";
    String standard_name_vocabulary "CF Standard Name Table v70";
    String summary "Visible and Infrared Imager/Radiometer Suite/Suomi-NPP (VIIRSN) Level-3 Standard Mapped Image (WW00)";
    String temporal_range "day";
    String testOutOfDate "now-5days";
    String time_coverage_end "2021-04-21T12:00:00Z";
    String time_coverage_start "2018-08-09T12:00:00Z";
    String title "Chlorophyll, Blended NOAA-SNPP and NOAA-20 VIIRS, Near Real-Time, Global, Level 3, 0.0375°, 2018-present EXPERIMENTAL, Daily";
    Float64 Westernmost_Easting -179.9812;
  }
}

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.