ERDDAP > griddap > Data Access Form

Dataset Title:	Unbiased Relative Difference of Net Primary Productivity, VIIRS SNPP vs MODIS Aqua, 9Km, Monthly, 2013-2022, Global
Institution:	NOAA/NESDIS/STAR/CoastWatch/West Coast   (Dataset ID: netpp_psi_snpp_modis)
Information:	Summary | License | FGDC | ISO 19115 | Metadata | Background | Files | Make a graph

 

Dimensions	Start	Stride	Stop	Size	Spacing
time (Centered Time, UTC)				120	30 days 10h 17m 9s (uneven)
latitude (degrees_north)				2160	-0.08333334 (uneven)
longitude (degrees_east)				4320	0.08333332 (uneven)

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

psi (Absolute Relative Difference of Net Primary Productivity, 1)

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). .parquet - Download as a parquet file. Metadata contains column names ("column_names") and units ("column_units"). .parquetWMeta - Download as a parquet file with detailed metadata. .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)
 
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 1.3583232e+9, 1.6711776e+9;
    String axis "T";
    String calendar "gregorian";
    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";
    Float64 actual_range -89.95834, 89.95834;
    String axis "Y";
    String ioos_category "Location";
    String long_name "Latitude";
    String standard_name "latitude";
    String units "degrees_north";
    Float64 valid_max 90.0;
    Float64 valid_min -90.0;
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float64 actual_range -179.9583, 179.9583;
    String axis "X";
    String ioos_category "Location";
    String long_name "Longitude";
    String standard_name "longitude";
    String units "degrees_east";
  }
  psi {
    Float32 _FillValue -999.0;
    String colorBarContinuous "false";
    String colorBarMaximum "0.4";
    String colorBarMinimum "-0.4";
    Int32 colorBarNSections 8;
    String coverage_content_type "modelResult";
    String ioos_category "Other";
    String long_name "Absolute Relative Difference of Net Primary Productivity";
    Float32 missing_value -999.0;
    String source "NOAA CoastWatch West Coast Node";
    String units "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. Support was also provided by NOAA CoastWatch.";
    String cdm_data_type "Grid";
    String contributor "Dale Robinson, Isaac Schroeder";
    String contributor_role "development and project management, production code";
    String Conventions "COARDS, CF-1.6, ACDD-1.3";
    String creator_name "NOAA CoastWatch West Coast Node";
    String creator_type "institution";
    String creator_url "https://coastwatch.pfeg.noaa.gov/";
    Float64 Easternmost_Easting 179.9583;
    Float64 geospatial_lat_max 89.95834;
    Float64 geospatial_lat_min -89.95834;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 179.9583;
    Float64 geospatial_lon_min -179.9583;
    String geospatial_lon_units "degrees_east";
    String history 
"Tue Apr  9 13:19:40 2024: The unbiased relative difference was calculated from VIIRS-SNPP and MODIS-Aqua primary productivity data using Python code stored at https://github.com/CoastWatch-WestCoast/interim_primary_productivity
2025-05-01T11:44:13Z (local files)
2025-05-01T11:44:13Z https://coastwatch.pfeg.noaa.gov/wcn/erddap/griddap/netpp_psi_snpp_modis.das";
    String id "psi_primprod_snpp_monthly_9km";
    String infoUrl "https://coastwatch.pfeg.noaa.gov/projects/netpp";
    String institution "NOAA/NESDIS/STAR/CoastWatch/West Coast";
    String instrument "VIIRS, MODIS";
    String keywords "calculating, data, latitude, longitude, psi, summation, time";
    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 map_projection "geographic";
    String naming_authority "gov.noaa.pfeg.coastwatch";
    String NCO "netCDF Operators version 4.9.5 (Homepage = http://nco.sf.net, Code = https://github.com/nco/nco)";
    Float64 Northernmost_Northing 89.95834;
    String platform "NPP, Aqua";
    String proj4_string "+proj=eqc +lat_ts=0 +lat_0=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs +lon_0=0.000000";
    String project "NOAA CoastWatch Interim Primary Productivity";
    String publisher_name "NOAA/NMFS/SWFSC/ERD, NOAA/NESDIS/STAR/CoastWatch/West Coast Node";
    String publisher_type "group";
    String publisher_url "https://coastwatch.pfeg.noaa.gov";
    String references "Melina et al. Remote Sensing of Environment 203 (2017) 139–151, Behrenfeld and Falkowski. Limnol. Oceanogr. 42 (1997) 1-20.";
    String source "primary productivity measurements based on satellite observations from VIIRS-SNPP and MODIS-Aqua";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing -89.95834;
    String spatialResolution "9.28 km";
    String standard_name_vocabulary "CF Standard Name Table v70";
    String summary "The unbiased relative difference (Psi) between primary productivity (netPP) calculated using VIIRS-SNPP and MODIS-Aqua primary productivity data. For each pixel, psi is calculated as netPP(viirs)- netPP(modis) divided by the mean of netPP(viirs) and netPP(modis) as described by Mélina et al. 2017. Primary productivity was calculated as described by Behrenfeld and Falkowski 1997. This dataset contains pixel-by-pixel Psi for the globe for each month between January 2013 to December 2022 at 9 kilometer spatial resolution.";
    String time_coverage_end "2022-12-16T08:00:00Z";
    String time_coverage_resolution "P1M";
    String time_coverage_start "2013-01-16T08:00:00Z";
    String title 
"Unbiased Relative Difference of Net Primary Productivity, VIIRS SNPP vs MODIS Aqua, 9Km,
Monthly, 2013-2022, Global";
    Float64 Westernmost_Easting -179.9583;
  }
}

 

---

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 Data Access Protocol (DAP) and its 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
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.

 

---

ERDDAP, Version 2.26
Disclaimers | Privacy Policy | Contact