Changes between Version 3 and Version 4 of PointObservationConventions
 Timestamp:
 02/11/09 14:02:21 (11 years ago)
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PointObservationConventions
v3 v4 30 30 Some assumption are common to all representations: 31 31 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 33 35 34 36 == 5.8.1 Point Data == … … 72 74 73 75 Point 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 77 Some 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. 74 82 75 83 === 5.8.2.1 Multidimensional representation === … … 117 125 }}} 118 126 119 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.127 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. 120 128 121 129 The 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. … … 182 190 The 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. 183 191 184 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. 192 The 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. 185 193 186 194 === 5.8.2.3 Ragged array (noncontiguous) representation === … … 229 237 }}} 230 238 231 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. 239 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. 240 241 The 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. 236 242 237 243 === 5.8.2.4 Single station === 238 244 239 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 ; 245 When 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 {{{ 248 dimensions: 249 obs = 1233 ; 250 name_strlen = 23 244 251 245 252 variables: … … 253 260 alt:long_name = "altitude above MSL" ; 254 261 alt:units = "m" ; 262 char station_name(name_strlen) ; 263 station_name:long_name = "station name" ; 264 station_name:standard_name = "station_id"; 255 265 256 266 double time(obs) ;