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Tip

These conditions are combined together by the logical AND operator. So a row of data is only added to the results when all the conditions match.

Sample data

This is the list of the data files used for the examples:set of examples is based on file temp.bufr (click here for details). 

Anchor
bufr_files
bufr_files

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Extracting a single parameter

This set of examples is based on file temp.bufr (click here for details). This set of examples are based on file temp.bufr (see above).

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Extracting with a single coordinate condition

This set of examples are is based on file temp.bufr (see aboveclick here for details).

ExampleFilterResultsComments

For all the messages: extract the first temperature value which is greater than 300 K and also extract the pressure on which it occurs


Code Block
extract_data: on
parameter_1: airTemperature
parameter_operator_1: >
parameter_value_1: 300
coordinate_condition_count: 1
coordinate_1: pressure


Here we explicitly say the we only want the matching temperature values which appear inside a pressure block (in these messages this is always the case). By using the coordinate condition pressure will be extracted as well because the EXTRACT_COORDINATE option is On by default.
For all the messages: extract the first temperature value which is greater than 300 K and the pressure is less than 950 hPa


Code Block
extract_data: on
parameter_1: airTemperature
parameter_operator_1: >
parameter_value_1: 300
coordinate_condition_count: 1
coordinate_1: pressure
coordinate_operator_1: >
coordinate_value_1: 95000


Here we further refined the coordinate condition.
For all the messages: extract the temperature value on the 500 hPa pressure level


Code Block
extract_data: on
parameter_1: airTemperature
coordinate_condition_count: 1
coordinate_1: pressure
coordinate_operator_1: =
coordinate_value_1: 50000



For station 78016: extract the temperature on the second pressure level



Code Block
identifier_value: 78016
extract_data: on
parameter_1: airTemperature
coordinate_condition_count: 1
coordinate_1: pressure
coordinate_rank_1: 2


Here we restricted the filter for one station (message) only and  used a rank condition for the coordinate.
For station 78016: extract the temperature on the first 6 pressure levels


Code Block
identifier_value: 78016
extract_data: on
parameter_1: airTemperature
coordinate_condition_count: 1
coordinate_1: pressure
coordinate_rank_1: 1/2/3/4/5/6
extract_mode: all


For coordinate rank a list of values can be specified.
For station 78016: extract the temperature on the 925, 850 and 700 hPa pressure levels


Code Block
identifier_value: 78016
extract_data: on
parameter_1: airTemperature
coordinate_condition_count: 1
coordinate_1: pressure
coordinate_operator_1: =
coordinate_value_1: 92500/85000/70000
extract_mode: all



Extracting multiple parameters

This set of examples are is based on file temp.bufr (see aboveclick here for details).

ExampleFilterResultsComments

For all the messages: extract the first wind speed and wind direction values


Code Block
extract_data: on
parameter_1: windDirection
parameter_2: windSpeed



Note

The order of the parameters in extraction must match their order of appearance in the message. Otherwise the data alignment does not work properly. In our BUFR messages windDirection precedes windSpeed, so we have to use the same ordering in the filter definition.


For all the messages: extract the first wind speed and wind direction values and also extract their pressure


Code Block
extract_data: on
parameter_1: windDirection
parameter_2: windSpeed
coordinate_condition_count: 1
coordinate_1: pressure



For all the messages: extract wind speed and wind direction values on the 500 hPa pressure level


Code Block
extract_data: on
parameter_1: windDirection
parameter_2: windSpeed
coordinate_condition_count: 1
coordinate_1: pressure
coordinate_operator_1: =
coordinate_value_1: 50000



Extracting with multiple (nested) coordinate conditions

This set of examples are is based on file temp.bufr (see aboveclick here for details).

When we use multiple coordinate conditions these are supposed to conceptually be nested, i.e. there is an inner coordinate and the other, inner coordinates, are nested in it. This puts a constrain on the order the coordinate conditions are specified: the outer coordinate has to be specified first then the other coordinates in the nesting order.

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Tropical cyclone tracks

This set of examples are is based on file tropical_cyclone.bufr  (see above click here for details).

ExampleFilterResults

For the first message (storm IN-FA) extract the storm centre pressure values along the track for ensemble number =2


Code Block
message_index: 1
custom_condition_count: 1
custom_value_1: ensembleMemberNumber
custom_operator_1: =
custom_value_1: 2
extract_data: on
parameter_count: 1
parameter_1: pressureReducedToMeanSeaLevel
extract_mode: all


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