Subsetting Parameters For NCSS Point

Parameter Name Required Description & Possible Values Constraints Default
var yes Name(s) of variables (comma separated, no blanks), or all. Variables must be in the dataset description.  
stns no Specify a list of stations (comma separated, no blanks). Only on station datasets.  
latitude, longitude no Point location; units of degrees_east, degrees_north. Must be within the dataset bounding box.  
north, south, east, west no lat/lon bounding box; units of degrees_east, degrees_north. south < north, west < east; if crossing 180 meridian, use east boundary > 180  
time no Time as a W3C Date or present or all.   present
time_window no Use with time: how close a match; UDUNIT time unit string or W3C time duration 1 hour  
time_start, time_end, time_duration no Used to specify a time range (two of these must be present).
Times may be a W3C Date or present.
Duration is a UDUNIT time or W3C time duration.		 The requested time range must intersect the dataset time range.  
accept no The returned data format. netCDF, netCDF4, XML, CSV, WaterML2 (station only). CSV

Variable Subsetting

  • You must specify a list of valid variable names, or all.

Horizontal Spatial Subsetting

  • stations: you may specify (in order of precedence):
    1. a list of stations,
    2. a point location (find station closest to the point), or
    3. a lat/lon bounding box (all stations within the box). If none, use all.
  • points: you may specify a lat/lon bounding box. If none, use all.

Temporal Subsetting

  • For all types, you may specify a time range or a specific time. If none, return the time closest to the present.
  • A time range will request all features that intersect the range.
  • A time point will request the feature that is closest to that time, within the time window.
  • The time window defaults to one hour.
  • If you include time=all, then return all times.

Output Format (accept Parameter)

  • csv: Comma-separated values, one feature per line
  • xml: Collection of feature elements
  • netCDF: CF/NetCDF-3
  • netCDF4: CF/NetCDF-4 classic model
  • netCDF4ext: NetCDF-4 extended model
  • WaterML2: OGC WaterML 2.0 Timeseries (station only)

Spatial Subsetting

Station List

Station datasets only. A comma separated list of stations for this dataset. You can get the list of stations from the stations.xml.

Example:

&stns=LECO,LEST,LEVX

Single-Point Requests

Station datasets only. Find the station closest to the given latitude, longitude.

Example:

&latitude=40.2&longitude=61.8

Lat/lon Bounding Box

Specified with the params north, south, east and west. The north and south parameters are latitude values, and must be in units of degrees_north and lie between +/- 90. The east and west parameters are longitude values with units of degrees_east, and may be positive or negative, and will be interpreted modulo 360. The requested subset starts at the west longitude and goes eastward until the east longitude. Therefore, when crossing the dateline, the west edge may be greater than the east edge.

Example request:

&north=17.3&south=12.088&west=140.2&east=160.0

Temporal Subsetting

There are several ways to do temporal subsetting requests:

  • Default: If no temporal subseting is specified, the closest time to the current time is returned.
  • All time range: A shorthand to request all the time range in a dataset is setting the parameter time=all. This can also be done by providing a valid temporal range containing the entire dataset time range.
  • One single time: Passing the parameter time will get the time slice closest to the requested time if it is within the time range of the dataset.
  • Valid time range: A valid time range is defined with two of the three parameters: time_start, time_end, and time_duration.

Times (time, time_start, and time_end) must be specified as W3C Date or present and time_duration as a W3C time duration.

Examples of time query strings with valid temporal ranges:

  • time_start=2007-03-29T12:00:00Z&time_end=2007-03-29T13:00:00Z (between 12 and 1 pm Greenwich time)
  • time_start=present&time_duration=P3D (get 3 day forecast starting from the present)
  • time_end=present&time_duration=PT3H (get last 3 hours)
  • time=2007-03-29T12:00:00Z
  • time=present
  • time=all
# Request Query String
1 All of the data for the variable Temperature_pressure for the closest time to the current time. ?var=Temperature_pressure&temporal=all
2 All of the data for the variable Temperature_pressure available in a given time range. ?var=Temperature_pressure&time_start=2015-08-19Z&time_end=2015-08-20T12:00:00Z
3 All of the data for the variable Temperature_pressure for a specific time. ?var=Temperature_pressure&time=2015-09-06T00:00:00Z
4 Subset the data for the variable Temperature_pressure over a given lat/lon bounding box for a specific time. ?var=Temperature_pressure&time=2015-09-06T00:00:00Z&north=41&west=-109.05&east=-102.05&south=37
5 Temperature_pressure for every 5th point on the grid (deltax=deltay=5) ?var=Temperature_pressure&horizStride=5
6 Temperature_pressure for every 5th point on the grid over a given lat/lon bounding box. ?var=Temperature_pressure&north=41&west=-109.5&east=-102.5&south=37&horizStride=5
7 Temperature_pressure at a particular vertical level: 1000 mb (see note below). ?var=Temperature_pressure&vertCoord=1000
8 Air_temperature for stations named LECO, LEST, and LEVX. ?var=air_temperature&subset=stns&stns=LECO,LEST,LEVX