Data Access Form

Dataset Title:	Chlorophyll a Concentration, NPP VIIRS, 750m, Pacific Islands Region - CoastWatch - Monthly, 2012-present
Institution:	NOAA NESDIS STAR (Dataset ID: noaa_snpp_chla_monthly_750m_v2023)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Make a graph

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Dimensions	Size	Spacing
time (Time Baseline, UTC)	142	30 days 10h 22m 59s (uneven)

altitude (m)	1	(just one value)

latitude (degrees_north)	7201	-0.0075 (even)

longitude (degrees_east)	9201	0.0075 (even)

Grid Variables (which always also download all of the dimension variables)

chlor_a (Chlorophyll Concentration, OC3 Algorithm, mg m-3)

File type: (more information)

(Documentation / Bypass this form)

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

The Dataset Attribute Structure (.das) for this Dataset

Attributes {
  time {
    String _CoordinateAxisType "Time";
    Float64 actual_range 1.3267152e+9, 1.6974576e+9;
    String axis "T";
    String calendar "gregorian";
    String ioos_category "Time";
    String long_name "Time Baseline";
    String source_name "time_baseline";
    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";
    Float64 actual_range -19.99875000000001, 34.00125;
    String axis "Y";
    String ioos_category "Location";
    String long_name "Latitude";
    String source_name "rows";
    String standard_name "latitude";
    String units "degrees_north";
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float64 actual_range 139.99875000000003, 208.99874999999997;
    String axis "X";
    String ioos_category "Location";
    String long_name "Longitude";
    String source_name "cols";
    String standard_name "longitude";
    String units "degrees_east";
  }
  chlor_a {
    Float32 _FillValue NaN;
    Float64 colorBarMaximum 30.0;
    Float64 colorBarMinimum 0.03;
    String colorBarScale "Log";
    String cw_atmospheric_correction "NOAA MECB BMW Atmospheric Correction";
    Int32 cw_fraction_digits 0;
    String cw_processing_algorithm "OC3 Algorithm";
    String cw_product_status "Experimental";
    String ioos_category "Ocean Color";
    String long_name "Chlorophyll Concentration, OC3 Algorithm";
    Float32 missing_value NaN;
    String standard_name "mass_concentration_of_chlorophyll_in_sea_water";
    String units "mg m-3";
    Float32 valid_max 1000.0;
    Float32 valid_min 0.001;
  }
  NC_GLOBAL {
    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/NESDIS/STAR";
    String creator_type "institution";
    String creator_url "http://www.star.nesdis.noaa.gov/socd/mecb/color/";
    String cw_orbit_type "both";
    String cw_pass_type "day";
    Float64 cw_polygon_latitude 89.77125000000001, 89.77125000000001, 89.77125000000001, 89.77125000000001, 89.77125000000001, 78.52312500000001, 67.275, 56.02687500000001, 44.77875000000001, 44.77875000000001, 44.77875000000001, 44.77875000000001, 44.77875000000001, 56.02687500000001, 67.275, 78.52312500000001, 89.77125000000001;
    Float64 cw_polygon_longitude 59.96625000000003, 74.98312500000003, 90.00000000000003, 105.01687500000003, 120.03375000000003, 120.03375000000003, 120.03375000000003, 120.03375000000003, 120.03375000000003, 105.01687500000003, 90.00000000000003, 74.98312500000003, 59.96625000000003, 59.96625000000003, 59.96625000000003, 59.96625000000003, 59.96625000000003;
    String cw_processing_version "SCI_OC04.0_V1.30";
    String cw_projection "Geographic";
    String cw_satellite "S-NPP";
    String cw_sensor "VIIRS";
    String cw_software_name "MSL12";
    String cw_software_version "1.30";
    Int32 cw_swath_sync_lines 16;
    String cw_viirs_band_naming_convention "OBPG";
    String date_created "2023-11-11T04:34:53Z";
    Float64 Easternmost_Easting 208.99874999999997;
    Float64 geospatial_lat_max 34.00125;
    Float64 geospatial_lat_min -19.99875000000001;
    Float64 geospatial_lat_resolution 0.007500000000000001;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 208.99874999999997;
    Float64 geospatial_lon_min 139.99875000000003;
    Float64 geospatial_lon_resolution 0.007499999999999994;
    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";
    String grid_mapping__CoordinateAxisTypes "GeoX GeoY";
    String grid_mapping__CoordinateTransformType "Projection";
    Float64 grid_mapping_inverse_flattening 298.257223563;
    Float64 grid_mapping_longitude_of_prime_meridian 0.0;
    String grid_mapping_name "latitude_longitude";
    Float64 grid_mapping_semi_major_axis 6378137.0;
    String history 
"[cwutils 3.8.0.305 20230102_225324] cwcomposite --method geomean --inputs - --match ^(chlor_a)$ /home/pub/svc_cwatch/aps/aps_p/browse/lvl4/modis/coastwatch/maskhdf/VRSRCW_B2023274_B2023304_F31_YZ00_chlora.hdf
[cwutils 3.8.0.305 20230102_225324] cwgraphics /home/pub/svc_cwatch/aps/aps_p/browse/lvl4/modis/coastwatch/maskhdf/VRSRCW_B2023274_B2023304_F31_YZ00_chlora.hdf
2024-04-28T14:56:31Z (local files)
2024-04-28T14:56:31Z https://oceanwatch.pifsc.noaa.gov/erddap/griddap/noaa_snpp_chla_monthly_750m_v2023.das";
    String infoUrl "http://www.star.nesdis.noaa.gov/socd/mecb/color/";
    String institution "NOAA NESDIS STAR";
    String instrument "VIIRS";
    String keywords "algorithm, altitude, available, baseline, chemistry, chla, chlor_a, chlora, chlorophyll, chlorophyll-a, coefficients, color, color/ocean, cols, concentration, data, earth, Earth Science > Oceans > Ocean Chemistry > Chlorophyll, Earth Science > Oceans > Ocean Optics > Ocean Color/Ocean Turbidity/Water-Leaving Radiance/Extinction Coefficients, environmental, extinction, geometric, imager, imager/radiometer, imaging, information, infrared, leaving, mass, mass_concentration_of_chlorophyll_in_sea_water, mean, national, nesdis, noaa, npp, oc3, ocean, ocean color, oceans, optics, orbiting, par, partnership, photosynthetically, polar, polar-orbiting, radiance, radiance/extinction, radiation, radiometer, rows, s-npp, satellite, science, sea, seawater, service, star, suite, time, time_baseline, turbidity, turbidity/water-leaving, viirs, visible, water";
    String keywords_vocabulary "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.";
    Float64 Northernmost_Northing 34.00125;
    String OBSERVED_PROPERTY "chlor_a";
    String platform "S-NPP";
    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 source "S-NPP_VIIRS_chlora";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing -19.99875000000001;
    String standard_name_vocabulary "CF Standard Name Table v79";
    String summary "Ocean color standard products include normalized water-leaving radiances, chlorophyll-a concentration, diffusive attenuation coefficient at 490 nm and diffusive attenuation coefficient of the photosynthetically available radiation (PAR).";
    String time_coverage_end "2023-10-16T12:00:00Z";
    String time_coverage_start "2012-01-16T12:00:00Z";
    String title "Chlorophyll a Concentration, NPP VIIRS, 750m, Pacific Islands Region - CoastWatch - Monthly, 2012-present";
    Float64 Westernmost_Easting 139.99875000000003;
  }
}

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[(2015-06-09T09:00:00Z)][(-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.