Make A Graph

Dataset Title:	MODIS Rolling 8-day CHL climatology.
Institution:	University of Delaware (Dataset ID: aqua_chl_climatology_8day)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Data Access Form

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Graph Type:
X Axis:
Y Axis:
Color:

Dimensions

Start

Stop

time2 (DOY)

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 {
  time2 {
    Float64 actual_range 1.0, 366.0;
    String axis "T";
    String ioos_category "Time";
    String long_name "time";
    String units "DOY";
  }
  latitude {
    String _CoordinateAxisType "Lat";
    Float64 actual_range -89.95833587646484, 89.95833587646484;
    String axis "Y";
    String ioos_category "Location";
    String long_name "Latitude";
    String standard_name "latitude";
    String units "degrees_north";
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float64 actual_range -179.9583282470703, 179.95835876464844;
    String axis "X";
    String ioos_category "Location";
    String long_name "Longitude";
    String standard_name "longitude";
    String units "degrees_east";
  }
  chl_ocx {
    Float32 _FillValue 1.0e+32;
    String ioos_category "Unknown";
    String long_name "Chl Ocx";
    String units "chl";
  }
  NC_GLOBAL {
    String cdm_data_type "Grid";
    String Conventions "COARDS, CF-1.6, ACDD-1.3";
    Float64 Easternmost_Easting 179.95835876464844;
    Float64 geospatial_lat_max 89.95833587646484;
    Float64 geospatial_lat_min -89.95833587646484;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 179.95835876464844;
    Float64 geospatial_lon_min -179.9583282470703;
    String geospatial_lon_units "degrees_east";
    String history 
"2025-10-31T07:02:41Z (local files)
2025-10-31T07:02:41Z http://basin.ceoe.udel.edu/griddap/aqua_chl_climatology_8day.das";
    String infoUrl "orb.udel.edu";
    String institution "University of Delaware";
    String keywords "chl, chl_ocx, chlorophyll, data, local, ocx, source, time";
    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.";
    Float64 Northernmost_Northing 89.95833587646484;
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing -89.95833587646484;
    String standard_name_vocabulary "CF Standard Name Table v70";
    String summary "For each day of the calendar year, the average is the average of all the years for which this day is available, over the period 1997-2010. The average is computed in log space.";
    String title "MODIS Rolling 8-day CHL climatology.";
    Float64 Westernmost_Easting -179.9583282470703;
  }
}

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.