Make A Graph

Dataset Title:	Ice Classification, Metop-C Advanced SCATterometer (ASCAT), 4km, North Pole (Arctic), Daily
Institution:	USDOC/NOAA/NESDIS PolarWatch (Dataset ID: noaacwSARciceclassnpoleDaily)
Information:	Summary \| License \| 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 →

altitude (m)

specify just 1 value →

rows (m)

cols (m)

Graph Settings
Color Bar:	Continuity:	Scale:
Minimum:	Maximum:	N Sections:
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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[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 1.6386192e+9, 1.7140464e+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";
  }
  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";
  }
  rows {
    Float64 actual_range -3272748.091917, 3272748.092178;
    String axis "Y";
    String ioos_category "Location";
    String long_name "Northing of Pixel Centers";
    String standard_name "projection_y_coordinate";
    String units "m";
  }
  cols {
    Float64 actual_range -3272748.092178, 3272748.091917;
    String axis "X";
    String ioos_category "Location";
    String long_name "Easting of Pixel Centers";
    String standard_name "projection_x_coordinate";
    String units "m";
  }
  IceClass {
    Float64 _FillValue 0.0;
    String colorBarMaximum "5";
    String colorBarMinimum "1";
    String flag_meanings "Land Water Seasonal Mixed Perennial";
    String flag_values "1 2 3 4 5";
    String grid_mapping "polar_stereographic_proj";
    String ioos_category "Ice Distribution";
    String long_name "IceClass";
    Float64 missing_value 0.0;
  }
  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 CoastWatch/PolarWatch";
    String creator_type "institution";
    String creator_url "https://coastwatch.noaa.gov/";
    String crs_wkt "PROJCS[\"unnamed\", GEOGCS[\"WGS 84\", DATUM[\"WGS_1984\", SPHEROID[\"WGS 84\",6378137,298.257223563, AUTHORITY[\"EPSG\",\"7030\"]], AUTHORITY[\"EPSG\",\"6326\"]], PRIMEM[\"Greenwich\",0], UNIT[\"degree\",0.0174532925199433], AUTHORITY[\"EPSG\",\"4326\"]], PROJECTION[\"Polar_Stereographic\"], PARAMETER[\"latitude_of_origin\",60], PARAMETER[\"central_meridian\",-45], PARAMETER[\"scale_factor\",1], PARAMETER[\"false_easting\",0], PARAMETER[\"false_northing\",0], UNIT[\"metre\",1, AUTHORITY[\"EPSG\",\"9001\"]]]";
    String cw_projection "Polar Stereographic";
    String cw_satellite "Metop-C";
    String cw_sensor "ASCAT";
    String defaultGraphQuery "IceClass%5B(last)%5D%5B(0.0)%5D%5B(3272748.09217783):(-3272748.0921771)%5D%5B(-3272748.09217783):(3272748.0921771)%5D%26.draw=surface%26.vars=cols%7Crows%7CIceClass%26.colorBar=iceclass%7CD%7C%7C1%7C6%7C5%26.bgColor=0xffccccff";
    String geospatial_bounds "POLYGON((-180.000000 47.538530, 135.000000 59.302944, 90.000000 47.538530, 45.000000 59.302944, 0.000000 47.538530, -45.000000 59.302944, -90.000000 47.538530, -135.000000 59.302944, -180.000000 47.538530))";
    Float64 geospatial_vertical_max 0.0;
    Float64 geospatial_vertical_min 0.0;
    String geospatial_vertical_positive "up";
    String geospatial_vertical_units "m";
    Float64 grid_mapping_false_easting 0.0;
    Float64 grid_mapping_false_northing 0.0;
    Float64 grid_mapping_inverse_flattening 298.257223563;
    Float64 grid_mapping_latitude_of_projection_origin 90.0;
    String grid_mapping_name "polar_stereographic";
    Float64 grid_mapping_semi_major_axis 6378137.0;
    Float64 grid_mapping_standard_parallel 60.0;
    Float64 grid_mapping_straight_vertical_longitude_from_pole -45.0;
    String history 
"Metop-C_ASCAT_IceClass
2024-04-27T13:01:35Z (local files)
2024-04-27T13:01:35Z https://polarwatch.noaa.gov/griddap/noaacwSARciceclassnpoleDaily.das";
    String infoUrl "https://coastwatch.noaa.gov/";
    String institution "USDOC/NOAA/NESDIS PolarWatch";
    String instrument "ASCAT";
    String keywords "advanced, altitude, ascat, coastwatch, Earth Science > Oceans > Ice, environmental, geoprojected, ice, ice classification, ice distribution, information, masked, metop, metop-c, national, nesdis, noaa, polar, polarwatch, satellite, scatterometer, service, states, time, united, usdoc";
    String keywords_vocabulary "NASA Global Change Master Directory (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 OBSERVED_PROPERTY "IceClass";
    String platform "METOP-C";
    String proj4text "+proj=stere +lat_0=90 +lat_ts=60 +lon_0=-45 +k=1 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs";
    String publisher_email "coastwatch.info@noaa.gov";
    String publisher_name "NOAA/NESDIS/STAR/SOCD PolarWatch";
    String publisher_url "https://coastwatch.noaa.gov";
    String source "METOP-C_ASCAT_IceClass";
    String sourceUrl "(local files)";
    String standard_name_vocabulary "CF Standard Name Table v79";
    String summary "The ASCAT Ice Classification system takes Enhanced Resolution (4.5 km x 4.5 km) ASCAT Normalized Radar Cross Section (NRCS) and in a two-step process creates an Ice Classification mask with 3 classes (seasonal, perennial, mixed). Primary Input data Enhanced Resolution (4.5 km x 4.5 km) ASCAT Normalized Radar Cross Section (NRCS) created by the Scatterometer Image Reconstruction (SIR) algorithm. Developed by David Long at BYU. National Ice Center's 4 km Interactive Snow and Ice Mask (IMS). Warning: Microwave-based ASCAT sea ice classification may not be reliable during Northern summer months or melt periods (approximately May to September) because melting snow and ice have a distinct microwave radar return that may prevent accurate identification of ice type.";
    String testOutOfDate "now-4days";
    String time_coverage_end "2024-04-25T12:00:00Z";
    String time_coverage_start "2021-12-04T12:00:00Z";
    String title "Ice Classification, Metop-C Advanced SCATterometer (ASCAT), 4km, North Pole (Arctic), Daily";
  }
}

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.