Make A Graph

Dataset Title:	Chlorophyll-a and aCDOM(300). S3A/B OLCI, Long Island Sound, 300m, PROVISIONAL, Daily
Institution:	NOAA NESDIS CoastWatch (Dataset ID: noaacwappsS3ABcolorLISDaily)
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:
(Documentation / Bypass this form

)

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 1.6725744e+9, 1.7013456e+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 40.204, 41.5;
    String axis "Y";
    String ioos_category "Location";
    String long_name "Latitude";
    String positive "up";
    String standard_name "latitude";
    String units "degrees_north";
    Float64 valid_max 41.5;
    Float64 valid_min 40.2;
    Float64 valid_range 40.2, 41.5;
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float64 actual_range -74.0, -71.8049;
    String axis "X";
    String ioos_category "Location";
    String long_name "Longitude";
    String positive "up";
    String standard_name "longitude";
    String units "degrees_east";
    Float64 valid_max -71.8049;
    Float64 valid_min -74.0;
    Float64 valid_range -74.0, -71.8049;
  }
  chlor_a {
    Float64 _FillValue NaN;
    Float64 colorBarMaximum 100.0;
    Float64 colorBarMinimum 0.0;
    String cw_atmospheric_correction "POLYMER V4.16.1 Atmospheric Correction";
    String cw_processing_algorithm "LIS MLR Algorithm";
    String cw_product_status "Experimental";
    String ioos_category "Ocean Color";
    String long_name "Chlorophyll-a";
    String references "https://www.sciencedirect.com/science/article/pii/S1569843223000456";
    String source "S3A/B OLCI Rrs from POLYER AC, ESA snap mosaic, Chl-a from LIS MLR";
    String standard_name "mass_concentration_of_chlorophyll_a_in_sea_water";
    String units "mg m-3";
    Float64 valid_max 1000.0;
    Float64 valid_min 0.0;
    Float64 valid_range 0.0, 1000.0;
  }
  cdom {
    Float64 _FillValue NaN;
    Float64 colorBarMaximum 60.0;
    Float64 colorBarMinimum 0.0;
    String cw_atmospheric_correction "POLYMER V4.16.1 Atmospheric Correction";
    String cw_processing_algorithm "LIS MLR Algorithm";
    String cw_product_status "Experimental";
    String ioos_category "Ocean Color";
    String long_name "Absorption coefficient of Chromophoric Dissolved Organic Material at 300 nm";
    String references "dummyURL";
    String source "S3A/B OLCI Rrs from POLYER AC, ESA snap mosaic, aCDOM from LIS MLR";
    String units "m-1";
    Float64 valid_max 50.0;
    Float64 valid_min 0.0;
    Float64 valid_range 0.0, 50.0;
  }
  NC_GLOBAL {
    String acknowledgement "Support provided by NOAA CoastWatch and SeaGrant";
    String cdm_data_type "Grid";
    String Conventions "CF-1.10, COARDS, ACDD-1.3";
    String creator_email "coastwatch.info@noaa.gov";
    String creator_name "CoastWatch Applications Team";
    String creator_type "person";
    String creator_url "https://coastwatch.noaa.gov/cwn/index.html";
    String date_created "2024-01-14T21:29:54Z";
    Float64 Easternmost_Easting -71.8049;
    Float64 geospatial_lat_max 41.5;
    Float64 geospatial_lat_min 40.204;
    Float64 geospatial_lat_resolution 0.002699999999999999;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max -71.8049;
    Float64 geospatial_lon_min -74.0;
    Float64 geospatial_lon_resolution 0.002699999999999996;
    String geospatial_lon_units "degrees_east";
    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 
"L2 Rrs data derived with POLYMER atmospheric correction. Daily composites made with snap mosaic. Chlorophyll-a derived using an MLR algorithm developed for the Long Island Sound
2024-04-27T09:25:30Z (local files)
2024-04-27T09:25:30Z https://coastwatch.noaa.gov/griddap/noaacwappsS3ABcolorLISDaily.das";
    String infoUrl "https://www.sciencedirect.com/science/article/pii/S1569843223000456";
    String institution "NOAA NESDIS CoastWatch";
    String instrument "OLCI";
    String keywords "300m, 300nm, absorption, acdom, acdom(300nm), cdom, chla, chlor, chlor_a, chlorophyll, chlorophyll-a, chromophoric, coefficient, color, colored, concentration, copernicus, daily, data, day, dissolved, island, latitude, long, longitude, mass, mass concentration of chlorophyll in sea water, material, matter, ocean, ocean color, olci, organic, program, provisional, s3a, s3b, sea, seawater, sentinel, sound, time, water";
    String license "CC0-1.0";
    Float64 Northernmost_Northing 41.5;
    String platform "Sentinel-3A, Sentinel-3B";
    String references "https://www.sciencedirect.com/science/article/pii/S1569843223000456";
    String source_data "Sentinel-3A OLCI, Sentinel-3B OLCI";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing 40.204;
    String standard_name_vocabulary "CF Standard Name Table v79";
    String summary "Chlorophyll-a and aCDOM(300), S-3A/B OLCI, Long Island Sound, 300m, Experimental, Daily";
    String time_coverage_end "2023-11-30T12:00:00Z";
    String time_coverage_start "2023-01-01T12:00:00Z";
    String title "Chlorophyll-a and aCDOM(300). S3A/B OLCI, Long Island Sound, 300m, PROVISIONAL, Daily";
    Float64 Westernmost_Easting -74.0;
  }
}

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.