ERDDAP: CoastWatch Caribbean and Gulf of America Regional Node at NOAA/AOML Easier access to scientific data

Dataset Title:	KdPAR, NOAA S-NPP VIIRS, Near Real-Time, 750m Sector VY, Daily
Institution:	NOAA NESDIS CoastWatch   (Dataset ID: noaacwNPPVIIRSkdPARSectorVYDaily)
Information:	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). cdm_data_type = Grid VARIABLES (all of which use the dimensions [time][altitude][latitude][longitude]): kd_PAR (Diffuse Attenuation Coefficient for PAR, m^-1) swath_latitude (Latitude, degrees_north) swath_longitude (Longitude, degrees_east) graphics (graphics overlay planes) ')" onmouseout="UnTip()" > | 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.')" onmouseout="UnTip()" > | FGDC | ISO 19115 | Metadata | Background | Files | Make a graph

Dimensions	Start	Stride	Stop	Size	Spacing For your information: this is the average spacing between values of a dimension (in the units of the dimension) and an indication of whether the values are perfectly evenly spaced or not. A slightly odd, uneven spacing often indicates that one or a few files are missing or bad in an otherwise perfectly evenly spaced dataset.')" onmouseout="UnTip()" >
time (UTC)   Float64 time[88] {     String _CoordinateAxisType "Time";     Float64 actual_range 1.73748645565e+9, 1.745433906062e+9;     String axis "T";     String bounds "time_bounds";     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";   } ')" onmouseout="UnTip()" >				88	1 day 1h 22m 30s (uneven)
altitude (m)   Float64 altitude[1] {     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";   } ')" onmouseout="UnTip()" >				1	(just one value)
latitude (degrees_north)   Float64 latitude[6000] {     String _CoordinateAxisType "Lat";     Float64 actual_range -0.10875000000000629, 44.88374999999999;     String axis "Y";     String ioos_category "Location";     String long_name "Latitude";     String source_name "rows";     String standard_name "latitude";     String units "degrees_north";   } ')" onmouseout="UnTip()" >				6000	-0.0075 (even)
longitude (degrees_east)   Float64 longitude[8010] {     String _CoordinateAxisType "Lon";     Float64 actual_range -120.03375, -59.96625;     String axis "X";     String ioos_category "Location";     String long_name "Longitude";     String source_name "cols";     String standard_name "longitude";     String units "degrees_east";   } ')" onmouseout="UnTip()" >				8010	0.0075 (even)

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

kd_PAR (Diffuse Attenuation Coefficient for PAR, m^-1)   Float64 kd_PAR[time][altitude][latitude][longitude] {     Float64 _FillValue -32.768001556396484;     Float32 colorBarMaximum 6.0;     Float32 colorBarMinimum 0.01;     String colorBarScale "Log";     String coverage_content_type "physical_measurement";     String grid_mapping "coord_ref";     String ioos_category "Ocean Color";     String long_name "Diffuse Attenuation Coefficient for PAR";     Float64 missing_value -32.768001556396484;     String units "m^-1";     Float64 valid_max 32.00000151991844;     Float64 valid_min 0.01600000075995922;   } ')" onmouseout="UnTip()" >

swath_latitude (Latitude, degrees_north)   Float32 swath_latitude[time][altitude][latitude][longitude] {     Float32 _FillValue NaN;     Float64 colorBarMaximum 90.0;     Float64 colorBarMinimum -90.0;     String grid_mapping "coord_ref";     String ioos_category "Location";     String long_name "Latitude";     Float32 missing_value NaN;     String units "degrees_north";   } ')" onmouseout="UnTip()" >

swath_longitude (Longitude, degrees_east)   Float32 swath_longitude[time][altitude][latitude][longitude] {     Float32 _FillValue NaN;     Float64 colorBarMaximum 180.0;     Float64 colorBarMinimum -180.0;     String grid_mapping "coord_ref";     String ioos_category "Location";     String long_name "Longitude";     Float32 missing_value NaN;     String units "degrees_east";   } ')" onmouseout="UnTip()" >

graphics (graphics overlay planes)   Int16 graphics[time][altitude][latitude][longitude] {     Int16 _FillValue 0;     Float64 colorBarMaximum 20.0;     Float64 colorBarMinimum 0.0;     String grid_mapping "coord_ref";     String ioos_category "Other";     String long_name "graphics overlay planes";     Int16 missing_value 0;   } ')" onmouseout="UnTip()" >

File type: (more information) .asc - View OPeNDAP-style ISO-8859-1 comma-separated text. .csv - Download a ISO-8859-1 comma-separated text table (line 1: names; line 2: units; ISO 8601 times). .csvp - Download a ISO-8859-1 .csv file with line 1: name (units). Times are ISO 8601 strings. .csv0 - Download a ISO-8859-1 .csv file without column names or units. Times are ISO 8601 strings. .das - View the dataset's metadata via an ISO-8859-1 OPeNDAP Dataset Attribute Structure (DAS). .dds - View the dataset's structure via an ISO-8859-1 OPeNDAP Dataset Descriptor Structure (DDS). .dods - OPeNDAP clients use this to download the data in the DODS binary format. .esriAscii - Download an ISO-8859-1 ESRI ASCII file (latitude longitude data only; longitude must be all below or all above 180). .fgdc - View the dataset's UTF-8 FGDC .xml metadata. .graph - View a Make A Graph web page. .help - View a web page with a description of griddap. .html - View an OPeNDAP-style HTML Data Access Form. .htmlTable - View a UTF-8 .html web page with the data in a table. Times are ISO 8601 strings. .iso19115 - View the dataset's ISO 19115-2/19139 UTF-8 .xml metadata. .itx - Download an ISO-8859-1 Igor Text File. Each axis variable and each data variable becomes a wave. .json - View a table-like UTF-8 JSON file (missing value = 'null'; times are ISO 8601 strings). .jsonlCSV1 - View a UTF-8 JSON Lines CSV file with column names on line 1 (mv = 'null'; times are ISO 8601 strings). .jsonlCSV - View a UTF-8 JSON Lines CSV file without column names (mv = 'null'; times are ISO 8601 strings). .jsonlKVP - View a UTF-8 JSON Lines file with Key:Value pairs (missing value = 'null'; times are ISO 8601 strings). .mat - Download a MATLAB binary file. .nc - Download a NetCDF-3 binary file with COARDS/CF/ACDD metadata. .ncHeader - View the UTF-8 header (the metadata) for the NetCDF-3 .nc file. .ncml - View the dataset's structure and metadata as a UTF-8 NCML .xml file. .nccsv - Download a NetCDF-3-like 7-bit ASCII NCCSV .csv file with COARDS/CF/ACDD metadata. .nccsvMetadata - View the dataset's metadata as the top half of a 7-bit ASCII NCCSV .csv file. .ncoJson - Download a UTF-8 NCO lvl=2 JSON file with COARDS/CF/ACDD metadata. .odvTxt - Download time,latitude,longitude,otherVariables as an ODV Generic Spreadsheet File (.txt). .timeGaps - View a UTF-8 list of gaps in the time values which are larger than the median gap. .tsv - Download a ISO-8859-1 tab-separated text table (line 1: names; line 2: units; ISO 8601 times). .tsvp - Download a ISO-8859-1 .tsv file with line 1: name (units). Times are ISO 8601 strings. .tsv0 - Download a ISO-8859-1 .tsv file without column names or units. Times are ISO 8601 strings. .wav - Download a .wav audio file. All columns must be numeric and of the same type. .xhtml - View a UTF-8 XHTML (XML) file with the data in a table. Times are ISO 8601 strings. .geotif - View a grayscale GeoTIFF .tif file (for latitude longitude data; longitude must be all below or all above 180). .kml - View a Google Earth .kml file (for latitude, longitude data only). .smallPdf - View a small .pdf image file with a graph or map. .pdf - View a standard, medium-sized .pdf image file with a graph or map. .largePdf - View a large .pdf image file with a graph or map. .smallPng - View a small .png image file with a graph or map. .png - View a standard, medium-sized .png image file with a graph or map. .largePng - View a large .png image file with a graph or map. .transparentPng - View a .png image file (just the data, without axes, landmask, or legend).

(Documentation / Bypass this form) Optional: Bypass This Form
griddap lets you request data by sending a specially formed URL to the server. The URL identifies a dataset, the desired file type for the response, and the subset of data that you want to receive. This Data Access Form simplifies this task: when you click on the Submit button below, the URL is generated and sent to the server. If you click on Just generate the URL, you can see the URL that the form generates, without sending the URL to the server.

If you learn how to form the URLs, you won\'t have to use this form to get data.
You can write a computer program or script that automatically generates URLs, sends them to ERDDAP, and gets the data. For more information on forming the URLs, click on the Bypass this form link to see the griddap documentation.')" onmouseout="UnTip()" >
 
Submit (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 1.73748645565e+9, 1.745433906062e+9;
    String axis "T";
    String bounds "time_bounds";
    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";
    Float64 actual_range -0.10875000000000629, 44.88374999999999;
    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 -120.03375, -59.96625;
    String axis "X";
    String ioos_category "Location";
    String long_name "Longitude";
    String source_name "cols";
    String standard_name "longitude";
    String units "degrees_east";
  }
  kd_PAR {
    Float64 _FillValue -32.768001556396484;
    Float32 colorBarMaximum 6.0;
    Float32 colorBarMinimum 0.01;
    String colorBarScale "Log";
    String coverage_content_type "physical_measurement";
    String grid_mapping "coord_ref";
    String ioos_category "Ocean Color";
    String long_name "Diffuse Attenuation Coefficient for PAR";
    Float64 missing_value -32.768001556396484;
    String units "m^-1";
    Float64 valid_max 32.00000151991844;
    Float64 valid_min 0.01600000075995922;
  }
  swath_latitude {
    Float32 _FillValue NaN;
    Float64 colorBarMaximum 90.0;
    Float64 colorBarMinimum -90.0;
    String grid_mapping "coord_ref";
    String ioos_category "Location";
    String long_name "Latitude";
    Float32 missing_value NaN;
    String units "degrees_north";
  }
  swath_longitude {
    Float32 _FillValue NaN;
    Float64 colorBarMaximum 180.0;
    Float64 colorBarMinimum -180.0;
    String grid_mapping "coord_ref";
    String ioos_category "Location";
    String long_name "Longitude";
    Float32 missing_value NaN;
    String units "degrees_east";
  }
  graphics {
    Int16 _FillValue 0;
    Float64 colorBarMaximum 20.0;
    Float64 colorBarMinimum 0.0;
    String grid_mapping "coord_ref";
    String ioos_category "Other";
    String long_name "graphics overlay planes";
    Int16 missing_value 0;
  }
  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://coastwatch.noaa.gov/";
    String date_created "2025-04-24T20:46:55Z";
    Float64 Easternmost_Easting -59.96625;
    String geospatial_bounds "POLYGON((-120.03375 44.88375,-105.016875 44.88375,-90.0 44.88375,-74.983125 44.88375,-59.96625 44.88375,-59.96625 33.635625,-59.96625 22.3875,-59.96625 11.139375,-59.96625 -0.10875,-74.983125 -0.10875,-90.0 -0.10875,-105.016875 -0.10875,-120.03375 -0.10875,-120.03375 11.139375,-120.03375 22.3875,-120.03375 33.635625,-120.03375 44.88375))";
    Float64 geospatial_lat_max 44.88374999999999;
    Float64 geospatial_lat_min -0.10875000000000629;
    Float64 geospatial_lat_resolution 0.0075;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max -59.96625;
    Float64 geospatial_lon_min -120.03375;
    Float64 geospatial_lon_resolution 0.0075;
    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 history 
"[MSL12 1.30][cwutils 3.6.0.111 20200520_165650]
2025-05-02T00:15:26Z (local files)
2025-05-02T00:15:26Z http://cwcgom.aoml.noaa.gov:8080/erddap/griddap/noaacwNPPVIIRSkdPARSectorVYDaily.das";
    String id "noaacwNPPVIIRSkdPARSectorVYDaily";
    String infoUrl "http://coastwatch.noaa.gov/cw/satellite-data-products/ocean-color/near-real-time/viirs-single-sensor.html";
    String institution "NOAA NESDIS CoastWatch";
    String instrument "VIIRS";
    String keywords "algorithm, altitude, available, chemistry, coefficients, color, color/ocean, cols, concentration, daily, data, day, diffuse attenuation, earth, Earth Science > Oceans > Ocean Chemistry > Diffuse Attenuation, Earth Science > Oceans > Ocean Optics > Ocean Color/Ocean Turbidity/Water-Leaving Radiance/Extinction Coefficients, extinction, graphics, imager, imager/radiometer, imaging, infrared, kdPAR, latitude, leaving, longitude, mass, merge, national, npp, oc3, ocean, ocean color, oceans, optical, optical properties, optics, orbiting, overlay, par, partnership, photosynthetically, planes, polar, polar-orbiting, properties, radiance, radiance/extinction, radiation, radiometer, rows, s-npp, science, sea, seawater, star, suite, swath_latitude, swath_longitude, time, 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.";
    String naming_authority "gov.noaa.coastwatch";
    Float64 Northernmost_Northing 44.88374999999999;
    String OBSERVED_PROPERTY "kd_par";
    String platform "S-NPP";
    String processing_level "L2";
    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 "http://coastwatch.noaa.gov; http://www.ncei.noaa.gov/";
    String source "S-NPP_VIIRS_kdpar";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing -0.10875000000000629;
    String standard_name_vocabulary "CF Standard Name Table v29";
    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 "2025-04-23T18:45:06Z";
    String time_coverage_start "2025-01-21T19:07:35Z";
    String title "KdPAR, NOAA S-NPP VIIRS, Near Real-Time, 750m Sector VY, Daily";
    Float64 Westernmost_Easting -120.03375;
  }
}

Using griddap to Request Data and Graphs from Gridded Datasets

OPeNDAP

Data Access Protocol (DAP)

projection constraints

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
http://coastwatch.pfeg.noaa.gov/erddap/griddap/datasetID.fileType{?query}
For example,
http://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.