Data Access Form

Dataset Title:	VIIRSN, Suomi-NPP, Level-3 SMI, NASA, Global, 4km, Reflectance at 671 nm, v2016, 2012-2017, 8-Day, DEPRECATED
Institution:	NASA/GSFC OBPG (Dataset ID: erdVH3r6718day)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Files \| Make a graph

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Dimensions	Size	Spacing
time (Centered Time, UTC)	270	7 days 22h 50m 25s (uneven)

latitude (degrees_north)	4320	-0.04166667 (uneven)

longitude (degrees_east)	8640	0.04166667 (uneven)

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

r671 (Remote sensing reflectance at 671 nm, sr^-1)

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 1.3257216e+9, 1.5105312e+9;
    String axis "T";
    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 -89.97918, 89.97916;
    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 -179.9792, 179.9792;
    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;
  }
  r671 {
    Float32 _FillValue -0.015534;
    Float64 colorBarMaximum 0.004;
    Float64 colorBarMinimum 4.0e-5;
    String colorBarScale "Log";
    String ioos_category "Optical Properties";
    String long_name "Remote sensing reflectance at 671 nm";
    String standard_name "surface_ratio_of_upwelling_radiance_emerging_from_sea_water_to_downwelling_radiative_flux_in_air";
    String units "sr^-1";
    Float32 valid_max 0.1;
    Float32 valid_min -0.01;
  }
  NC_GLOBAL {
    String _lastModified "2017-11-30T11:34:22.000Z";
    String _NCProperties "version=1|netcdflibversion=4.4.1.1|hdf5libversion=1.8.18";
    String cdm_data_type "Grid";
    String Conventions "CF-1.6, COARDS, ACDD-1.3";
    String creator_email "data@oceancolor.gsfc.nasa.gov";
    String creator_name "NASA/GSFC/OBPG";
    String creator_type "group";
    String creator_url "https://oceandata.sci.gsfc.nasa.gov";
    String date_created "2017-11-30T11:34:22.000Z";
    Float64 Easternmost_Easting 179.9792;
    Float64 geospatial_lat_max 89.97916;
    Float64 geospatial_lat_min -89.97918;
    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 
"SNPP data files are downloaded ASAP from https://oceandata.sci.gsfc.nasa.gov/VIIRS-SNPP/Mapped/8-Day/4km/Rrs_671/ to NOAA NMFS SWFSC ERD (erd.data@noaa.gov).
NOAA NMFS SWFSC ERD (erd.data@noaa.gov) uses ERDDAP to add the time variable and slightly modify the metadata.
Direct read of HDF4 file through CDM library.
2024-11-22T13:31:42Z https://oceandata.sci.gsfc.nasa.gov/VIIRS/Mapped/8Day/4km/Rrs_671/
2024-11-22T13:31:42Z https://coastwatch.pfeg.noaa.gov/erddap/griddap/erdVH3r6718day.das";
    String identifier_product_doi_authority "https://dx.doi.org";
    String infoUrl "https://oceancolor.gsfc.nasa.gov/data/viirs-snpp/";
    String institution "NASA/GSFC OBPG";
    String instrument "VIIRS";
    String keywords "4km, 671nm, 8-day, composite, gsfc, image, joint, jpss, level, level-3, mapped, mean, nasa, noaa, npoess, npp, obpg, ocean, ocean color, oceans, optical, orbiting, polar, properties, reflectance, remote, satellite, sea, seawater, sensing, smi, standard, suomi, viirs, viirsn, water";
    String keywords_vocabulary "GCMD Science Keywords";
    String l2_flag_names "ATMFAIL,LAND,HILT,HISATZEN,STRAYLIGHT,CLDICE,COCCOLITH,LOWLW,CHLWARN,CHLFAIL,NAVWARN,MAXAERITER,ATMWARN,HISOLZEN,NAVFAIL,FILTER,HIGLINT";
    String license 
"https://science.nasa.gov/earth-science/earth-science-data/data-information-policy/
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 measure "Mean";
    String naming_authority "gov.noaa.pfeg.coastwatch";
    Float64 Northernmost_Northing 89.97916;
    String platform "Suomi-NPP";
    String processing_level "L3 Mapped";
    String processing_version "2014.0.2";
    String project "Ocean Biology Processing Group (NASA/GSFC/OBPG)";
    String publisher_email "data@oceancolor.gsfc.nasa.gov";
    String publisher_name "NASA/GSFC/OBPG";
    String publisher_url "https://oceandata.sci.gsfc.nasa.gov";
    String sourceUrl "https://oceandata.sci.gsfc.nasa.gov/VIIRS/Mapped/8Day/4km/Rrs_671/";
    Float64 Southernmost_Northing -89.97918;
    String spatialResolution "4.64 km";
    String standard_name_vocabulary "CF Standard Name Table v70";
    String summary "THIS VERSION WAS DISCONTINUED on 2017-12-01. SEE THE NEW erdVH2018 DATASETS. Level-3 Standard Mapped Image (SMI), Global, 4km, Remote Sensing Reflectance at 671 nm, 8-Day composite data from the Visible and Infrared Imager/Radiometer Suite (VIIRS), as processed by NASA GSFC Ocean Biology Processing Group (OBPG). VIIRS is a multi-disciplinary instrument that flies on the Suomi-NPP (National Polar-orbiting Partnership) satellite.  Suomi-NPP is the initial spacecraft in the JPSS (Joint Polar Satellite Systems) series of spacecraft. JPSS is our Nation's next generation polar-orbiting operational environmental satellite system. JPSS is a collaborative program between NOAA and its acquisition agent NASA. VIIRS is the successor to MODIS for Earth science data product generation. (This version of the VH data was first released on 2016-04-01.)";
    String temporal_range "8-day";
    String time_coverage_end "2017-11-13T00:00:00Z";
    String time_coverage_start "2012-01-05T00:00:00Z";
    String title "VIIRSN, Suomi-NPP, Level-3 SMI, NASA, Global, 4km, Reflectance at 671 nm, v2016, 2012-2017, 8-Day, DEPRECATED";
    Float64 Westernmost_Easting -179.9792;
  }
}

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.