dballe types¶
Measured variables¶
A measured variable is represented by a dballe.Var
object, which
contains a value (int, float, or str) annotated with information in a
dballe.Varinfo
object.
dballe.Varinfo
objects are catalogued in dballe.Vartable
tables, which associate WMO B variable codes (like B12101
) to name,
descriptions, measurement units, significant digits, and so on.
dballe.Var
, dballe.Varinfo
, and dballe.Vartable
come
via wreport, and dballe.txt contents (see btable) can be accessed
with the shortcut functions dballe.varinfo()
and dballe.var()
.
- class dballe.Var¶
Var holds a measured value, which can be integer, float or string, and a
Varinfo
with all available information (description, unit, precision, …) related to it.Var objects can be created from a
Varinfo
object, and an optional value. Omitting the value creates an unset variable.Examples:
table = wreport.Vartable.get_bufr(master_table_version_number=24) v = wreport.Var(table["B12101"], 32.5) # v.info returns detailed informations about the variable in a Varinfo object. print("%s: %s %s %s" % (v.code, str(v), v.info.unit, v.info.desc))
Constructor: Var(varinfo: Union[wreport.Varinfo, wreport.Var], value: Union[str, int, float] = None)
If the variable is a scaled decimal, getting and setting its value using integers or strings will use the raw unscaled representation of its value. This provides a way to work with the exact underlying representation of values, without dealing with the potential limitations of floating point representations.
- code¶
variable code
- enq() Union[str, float, int] ¶
get the value of the variable, as int, float or str according the variable definition
- enqa(code: str) Optional[wreport.Var] ¶
get the variable for the attribute with the given code, or None if not found
- enqc() str ¶
get the value of the variable, as a str
If the variable is a scaled decimal value, this returns its unscaled integer representation. This provides a way to work with the exact underlying representation of values, without dealing with the potential limitations of floating point representations.
- enqd() float ¶
get the value of the variable, as a float
- enqi() int ¶
get the value of the variable, as an int
If the variable is a scaled decimal value, this returns its unscaled integer representation. This provides a way to work with the exact underlying representation of values, without dealing with the potential limitations of floating point representations.
- format(default: str=) str ¶
return a string with the formatted value of the variable
- get(default: Any = None) Union[str, float, long, Any] ¶
get the value of the variable, as int, float or str according the variable definition. If the variable is unset,
default
is returned
- get_attrs() List[wreport.Var] ¶
get the attributes of this variable
- info¶
Varinfo for this variable
- isset¶
true if the value is set
- seta(var: wreport.Var)¶
set an attribute in the variable
- unseta(code: str)¶
unset the given attribute from the variable
- class dballe.Varinfo¶
Varinfo object holds all possible information about a variable, such as its measurement unit, description and number of significant digits.
Varinfo objects cannot be instantiated directly, and are created by querying
Vartable
objects.- bit_len¶
number of bits used to encode the value in BUFR
- bit_ref¶
reference value added after scaling, for BUFR decoding
- code¶
variable code
- desc¶
description
- len¶
number of significant digits
- scale¶
scale of the value as a power of 10
- type¶
return a string describing the type of the variable (string, binary, integer, decimal)
- unit¶
measurement unit
- class dballe.Vartable¶
Collection of Varinfo objects indexed by WMO BUFR/CREX table B code.
A Vartable is instantiated by one of the
get_bufr()
,get_crex()
,load_bufr()
,load_crex()
class methods:table = wreport.Vartable.get_bufr(master_table_version_number=23) print(table["B12101"].desc)
- get_bufr(basename: str = None, originating_centre: int = 0, originating_subcentre: int = 0, master_table_number: int = 0, master_table_version_number: int = None, master_table_version_number_local: int = 0) wreport.Vartable ¶
Look up a table B file using the information given, then load BUFR information from it.
You need to provide either basename or master_table_version_number.
- Parameters:
basename – load the table with the given name in
/usr/share/wreport/
originating_centre – originating centre for the table data
originating_subcentre – originating subcentre for the table data
master_table_number – master table number for the table data
master_table_version_number – master table version number for the table data
master_table_version_number_local – local master table version number for the table data
- get_crex(basename: str = None, edition_number=2, originating_centre: int = 0, originating_subcentre: int = 0, master_table_number: int = 0, master_table_version_number: int = None, master_table_version_number_bufr: int = None, master_table_version_number_local: int = 0) wreport.Vartable ¶
Look up a table B file using the information given, then load CREX information from it.
You need to provide either basename or master_table_version_number or master_table_version_number_bufr.
- Parameters:
basename – load the table with the given name in
/usr/share/wreport/
edition_number – edition number for the table data
originating_centre – originating centre for the table data
originating_subcentre – originating subcentre for the table data
master_table_number – master table number for the table data
master_table_version_number – master table version number for the table data
master_table_version_number_bufr – BUFR master table version number for the table data
master_table_version_number_local – local master table version number for the table data
- load_bufr(pathname: str) wreport.Vartable ¶
Load BUFR information from a Table B file and return it as a wreport.Vartable.
- Parameters:
pathname – pathname of the file to load
- load_crex(pathname: str) wreport.Vartable ¶
Load CREX information from a Table B file and return it as a wreport.Vartable.
- Parameters:
pathname – pathname of the file to load
- pathname¶
name of the table
- dballe.varinfo(str) dballe.Varinfo ¶
Query the DB-All.e variable table returning a Varinfo
- dballe.var(code, val: Any = None) dballe.Var ¶
Query the DB-All.e variable table returning a Var, optionally initialized with a value
Variable metadata¶
dballe.Level
, dballe.Trange
, dballe.Station
, and
dballe.DBStation
, together with python’s datetime.datetime
class,
can be used to describe the DB-All.e metadata for measured variables, as
shortcuts for groups of closely related values.
The difference between dballe.Station
and dballe.DBStation
is
that the DB
version also contains the database ID as ana_id
.
DB-All.e also provides dballe.describe_level()
and dballe.describe_trange()
to turn level and timerange information into a string describing them.
- class dballe.Level¶
Level or layer.
Constructor: Level(ltype1: int=None, l1: int=None, ltype2: int=None, l2: int=None)
- describe()¶
Return a string description for this level
- l1¶
value of the level or of the first layer
- l2¶
value of the second layer
- ltype1¶
type of the level or of the first layer
- ltype2¶
type of the second layer
- class dballe.Trange¶
Time range.
Constructor: Trange(pind: int=None, p1: int=None, p2: int=None)
- describe()¶
Return a string description for this time range
- p1¶
Time range P1 indicator
- p2¶
Time range P2 indicator
- pind¶
Time range type indicator
- class dballe.Station¶
Station information.
Constructor: Station(report: str, lat: float, lon: float, ident: str=None)
- ident¶
mobile station identifier
- ilat¶
station latitude (as integer)
- ilon¶
station longitude (as integer)
- lat¶
station latitude
- lon¶
station longitude
- report¶
report for this station
- class dballe.DBStation¶
Station information with database ID.
Constructor: Station(report: str, id: int, lat: float, lon: float, ident: str=None)
- id¶
database ID for this station
- ident¶
mobile station identifier
- ilat¶
station latitude (as integer)
- ilon¶
station longitude (as integer)
- lat¶
station latitude
- lon¶
station longitude
- report¶
report for this station
- dballe.describe_level(ltype1: int, l1: int = None, ltype2: int = None, l2: int = None) str ¶
Return a string description for a level
- dballe.describe_trange(pind: int, p1: int = None, p2: int = None) str ¶
Return a string description for a time range
Variables and their metadata¶
dballe.Data
finally provides a way to group together one or more
variables and their metadata.
- class dballe.Data¶
key-value representation of a value with its associated metadata.
This is used when inserting values in a database, and can be indexed and assigned using insert parameters: see Parameters used when inserting values for a list.
Indexing by variable code also works. Assignment can take None, int, str, float, or a wreport.Var object. Assigning a wreport.Var object with a different varcode performs automatic unit conversion if possible.
See Convert values from one B code to another for an example.