Make A Graph

Dataset Title:	Chlorophyll-a, Orbview-2 SeaWiFS, R2018.0, 0.1°, Global, 1997-2010 (8 Day Composite)
Institution:	NASA/GSFC OBPG (Dataset ID: erdSW2018chla8day)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Data Access Form \| Files

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Graph Type:
X Axis:
Y Axis:
Color:

Dimensions

Start

Stop

time (UTC)

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 8.731584e+8, 1.2923712e+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 -89.95834, 89.95834;
    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 -179.9583, 179.9584;
    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;
  }
  chlorophyll {
    Float32 _FillValue -32767.0;
    Float64 colorBarMaximum 30.0;
    Float64 colorBarMinimum 0.03;
    String colorBarScale "Log";
    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 "concentration_of_chlorophyll_in_sea_water";
    String units "mg m^-3";
    Float32 valid_max 100.0;
    Float32 valid_min 0.001;
  }
  NC_GLOBAL {
    String _lastModified "2018-01-31T04:43:48.000Z";
    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 "2018-01-31T04:43:48.000Z";
    Float64 Easternmost_Easting 179.9584;
    Float64 geospatial_lat_max 89.95834;
    Float64 geospatial_lat_min -89.95834;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 179.9584;
    Float64 geospatial_lon_min -179.9583;
    String geospatial_lon_units "degrees_east";
    String grid_mapping_name "latitude_longitude";
    String history 
"These R2018.0 data files were downloaded from https://oceandata.sci.gsfc.nasa.gov/SeaWiFS/Mapped/8Day/9km/chlor_a to NOAA NMFS SWFSC ERD by erd.data@noaa.gov on 2018-03-05.
2024-11-04T23:41:19Z (local files)
2024-11-04T23:41:19Z https://coastwatch.pfeg.noaa.gov/griddap/erdSW2018chla8day.das";
    String identifier_product_doi "10.5067/ORBVIEW-2/SEAWIFS/L3M/CHL/2018";
    String identifier_product_doi_authority "https://dx.doi.org";
    String infoUrl "https://oceandata.sci.gsfc.nasa.gov";
    String institution "NASA/GSFC OBPG";
    String instrument "SeaWiFS";
    String keywords "algorithm, biology, center, chemistry, chlor_a, chlorophyll, color, concentration, concentration_of_chlorophyll_in_sea_water, data, Earth Science > Oceans > Ocean Chemistry > Chlorophyll, Earth Science > Oceans > Ocean Optics > Ocean Color, field, field-of-view, flight, goddard, group, gsfc, image, L3, level, level-3, mapped, nasa, noaa, obpg, ocean, ocean color, oceans, oci, optics, orbview, orbview-2, palette, processing, sea, sea-wide, seawater, seawifs, sensor, smi, space, standard, view, water, wide";
    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/
        
Please cite: NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group. Sea-viewing Wide Field-of-view Sensor (SeaWiFS) R2018.0 Chlorophyll Data; NASA OB.DAAC, Greenbelt, MD, USA. doi: https://dx.doi.org/10.5067/ORBVIEW-2/SEAWIFS/L3M/CHL/2018 .

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 89.95834;
    String platform "Orbview-2";
    String processing_level "L3 Mapped";
    String processing_version "2018.0";
    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_type "group";
    String publisher_url "https://oceandata.sci.gsfc.nasa.gov";
    String references 
"SeaWiFS information: https://oceancolor.gsfc.nasa.gov/SeaWiFS/ . NASA Ocean
Color information: https://oceancolor.gsfc.nasa.gov/
Processing reference: O'Reilly, J.E., Maritorena, S., Mitchell, B.G., Siegel, D.A., Carder, K.L., Garver, S.A., Kahru, M. and McClain, C. (1998). Ocean color chlorophyll algorithms for SeaWiFS. J. Geophys. Res., 103: 24, 937-24, 953.
Processing reference: O'Reilly, J. E., and 21 others. 2000. Ocean color chlorophyll a algorithms for SeaWiFS, OC2 and OC4: Version 4. SeaWiFS Postlaunch Calibration and Validation Analyses, part 3. NASA SeaWiFS technical report series. pp. 8 226 22.
Processing reference: Fu, G., Baith, K. S., and McClain, C. R. (1998). SeaDAS: The SeaWiFS Data Analysis System. Proceedings of \"The 4th Pacific Ocean Remote Sensing Conference\", Qingdao, China, July 28-31, 1998, 73-79.
Validation reference: Hooker, S.B., and C.R. McClain (2000). The Calibration and Validation of SeaWiFS Data. Prog. Oceanogr., 45, 427-465.
R2014.0 processing reference: 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.
R2018.0 reprocessing information: https://oceancolor.gsfc.nasa.gov/reprocessing/r2018/seawifs/";
    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 
"NASA GSFC Ocean Color Web distributes science-quality chlorophyll-a
concentration data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS)
on the Orbview-2 satellite. This version is the 2018.0 Reprocessing (R2018.0).
https://oceancolor.gsfc.nasa.gov/reprocessing/r2018/seawifs/

The SeaWiFS instrument was launched by Orbital Sciences Corporation on the
OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from
September 1997 until the end of mission in December 2010. SeaWiFS had 8
spectral bands from 412 to 865 nm. It collected global data at 4 km
resolution, and local data (limited onboard storage and direct broadcast)
at 1 km. The mission and sensor were optimized for ocean color measurements,
with a local noon (descending) equator crossing time orbit, fore-and-aft
tilt capability, full dynamic range, and low polarization sensitivity.";
    String temporal_range "10-hour";
    String time_coverage_end "2010-12-15T00:00:00Z";
    String time_coverage_start "1997-09-02T00:00:00Z";
    String title "Chlorophyll-a, Orbview-2 SeaWiFS, R2018.0, 0.1°, Global, 1997-2010 (8 Day Composite)";
    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 (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.