Changes between Version 3 and Version 4 of PointObservationConventions


Ignore:
Timestamp:
02/11/09 14:02:21 (11 years ago)
Author:
caron
Comment:

clarify 5.8.2.4 still needs station_id variable

Legend:

Unmodified
Added
Removed
Modified
  • PointObservationConventions

    v3 v4  
    3030Some assumption are common to all representations:
    3131 
    32     * index numbering is always 0 based.
     32    * lat, lon and time coordinates must always exist
     33    * index numbering, if used, is always 0 based
     34    * variables are associated together by having a common, outer dimension
    3335
    3436== 5.8.1 Point Data ==
     
    7274
    7375Point data may be taken at a set of named locations called stations. The set of observations at a particular station, if ordered by time, is a time series, and the file contains a collection of time series data at named locations called stations.
     76
     77Some assumption are common to all station representations:
     78
     79   * The outer dimension of the latitude and longitude coordinates (which must agree) is the 'station dimension'.
     80   * All variables that have the station dimension as their outer dimension are considered to be station information, and are called 'station variables'.
     81   * There must always be a station variable (of any type) with standard_name attribute "'''station_id'''", whose values uniquely identify the station.
    7482
    7583=== 5.8.2.1 Multidimensional representation ===
     
    117125}}}
    118126
    119 The humidity(s,i) and temp(s,i) data are associated with the coordinate values time(s,i), lat(s), lon(s), and optionally vertical(s). The station dimension may be the unlimited dimension or not. All variables that have station as their outer dimension are considered to be station information. There must be a station variable (of any type) with standard_name attribute "'''station_id'''", whose values uniquely identify the station.
     127The humidity(s,i) and temp(s,i) data are associated with the coordinate values time(s,i), lat(s), lon(s), and optionally vertical(s). The station dimension may be the unlimited dimension or not.
    120128
    121129The time coordinate may use a missing value, which indicates that data is missing for that station and obs index. This allows one to have a variable number of observations at different stations, at the cost of some wasted space. The data variables may also use missing data values, to indicate that just that data variable is missing.
     
    182190The rowSize variable contains the number of observations for each station, and is identified by having a standard_name of "'''ragged_rowSize'''". It must have the station dimension as its single dimension.
    183191
    184 All variables that have station as their outer dimension are considered to be station information. There must be a station variable (of any type) with standard_name attribute "'''station_id'''", whose values uniquely identify the station.
     192The outer dimension of the time coordinate is the obs dimension. All variables having the obs dimension as their outer dimension are observation variables. The obs dimension may use the unlimited dimension or not.
    185193
    186194=== 5.8.2.3 Ragged array (non-contiguous) representation ===
     
    229237}}}
    230238
    231 The humidity(i) and temp(i) data are associated with the coordinate values time(i), lat(s), lon(s), and optionally alt(s), where s = stationIndex(i). The stationIndex variable is identified by having a standard_name of "'''ragged_parentIndex'''". It must have the obs dimension as its single dimension.
    232 
    233 All variables that have station as their only dimension are considered to be information about that station. The obs dimension may use the unlimited dimension or not.
    234 
    235 All variables that have station as their outer dimension are considered to be station information. There must be a station variable (of any type) with standard_name attribute "'''station_id'''", whose values uniquely identify the station.
     239The humidity(i) and temp(i) data are associated with the coordinate values time(i), lat(s), lon(s), and optionally alt(s), where s = stationIndex(i). The stationIndex variable is identified by having a standard_name of "'''ragged_parentIndex'''".  It must have the obs dimension as its single dimension.
     240
     241The outer dimension of the time coordinate is the obs dimension. All variables having the obs dimension as their outer dimension are observation variables. The obs dimension may use the unlimited dimension or not.
    236242
    237243=== 5.8.2.4 Single station ===
    238244
    239 When there is only a single station in the file, one can can use any of the above representations, with number of stations = 1. One can also use scalar coordinates:
    240 
    241 {{{
    242 dimensions:
    243   obs = 13 ;
     245When there is a single station in the file, one can can use any of the above representations with number of stations = 1. One can also use scalar coordinates. This case is identified when the lat and lon coordinates are scalar. In this case, no connecting variable between station and observations is required.
     246
     247{{{
     248dimensions:
     249  obs = 1233 ;
     250  name_strlen = 23
    244251
    245252variables:
     
    253260    alt:long_name = "altitude above MSL" ;
    254261    alt:units = "m" ;
     262  char station_name(name_strlen) ;
     263    station_name:long_name = "station name" ;
     264    station_name:standard_name = "station_id";
    255265
    256266  double time(obs) ;