VAPoR  3.0.0
Classes | Public Types | Public Member Functions | Static Public Member Functions | List of all members
VAPoR::DC Class Referenceabstract

Defines API for reading a collection of data. More...

#include <DC.h>

Inheritance diagram for VAPoR::DC:
VetsUtil::MyBase VAPoR::DCWRF VAPoR::VDC VAPoR::VDCNetCDF

Classes

class  Attribute
 Variable or global metadata. More...
 
class  BaseVar
 Base class for storing variable metadata. More...
 
class  CoordVar
 Coordinate variable metadata. More...
 
class  DataVar
 Data variable metadata. More...
 
class  Dimension
 Metadata describing a coordinate dimension. More...
 

Public Types

enum  XType {
  INVALID = -1, FLOAT, DOUBLE, INT32,
  INT64, TEXT
}
 External storage types for primitive data. More...
 
- Public Types inherited from VetsUtil::MyBase
typedef void(* ErrMsgCB_T) (const char *msg, int err_code)
 
typedef void(* DiagMsgCB_T) (const char *msg)
 

Public Member Functions

 DC ()
 
virtual ~DC ()
 
virtual int Initialize (const vector< string > &paths)=0
 
virtual bool GetDimension (string dimname, DC::Dimension &dimension) const =0
 
virtual std::vector< string > GetDimensionNames () const =0
 
virtual bool GetCoordVarInfo (string varname, DC::CoordVar &cvar) const =0
 
virtual bool GetDataVarInfo (string varname, DC::DataVar &datavar) const =0
 
virtual bool GetBaseVarInfo (string varname, DC::BaseVar &var) const =0
 
virtual std::vector< string > GetDataVarNames () const =0
 
virtual std::vector< string > GetCoordVarNames () const =0
 
virtual int GetNumRefLevels (string varname) const =0
 
virtual int GetAtt (string varname, string attname, vector< double > &values) const =0
 
virtual int GetAtt (string varname, string attname, vector< long > &values) const =0
 
virtual int GetAtt (string varname, string attname, string &values) const =0
 
virtual std::vector< string > GetAttNames (string varname) const =0
 
virtual XType GetAttType (string varname, string attname) const =0
 
virtual int GetDimLensAtLevel (string varname, int level, std::vector< size_t > &dims_at_level, std::vector< size_t > &bs_at_level) const =0
 
virtual int GetMapProjection (string lonname, string latname, string &projstring) const =0
 
virtual int OpenVariableRead (size_t ts, string varname, int level=0, int lod=0)=0
 
virtual int CloseVariable ()=0
 
virtual int Read (float *data)=0
 
virtual int ReadSlice (float *slice)=0
 
virtual int ReadRegion (const vector< size_t > &min, const vector< size_t > &max, float *region)=0
 
virtual int ReadRegionBlock (const vector< size_t > &min, const vector< size_t > &max, float *region)=0
 
virtual int GetVar (string varname, int level, int lod, float *data)=0
 
virtual int GetVar (size_t ts, string varname, int level, int lod, float *data)=0
 
virtual bool VariableExists (size_t ts, string varname, int reflevel=0, int lod=0) const =0
 
virtual bool GetDimension (string dimname, size_t &length, int &axis) const
 
virtual std::vector< string > GetDataVarNames (int ndim, bool spatial) const
 
virtual std::vector< string > GetCoordVarNames (int ndim, bool spatial) const
 
virtual bool IsTimeVarying (string varname) const
 
virtual bool IsCompressed (string varname) const
 
virtual int GetNumTimeSteps (string varname) const
 
virtual int GetCRatios (string varname, vector< size_t > &cratios) const
 
virtual bool IsDataVar (string varname) const
 
virtual bool IsCoordVar (string varname) const
 
virtual int GetMapProjection (string varname, string &projstring) const
 
- Public Member Functions inherited from VetsUtil::MyBase
 MyBase ()
 
const string & getClassName () const
 

Static Public Member Functions

static bool ParseDimensions (const vector< DC::Dimension > &dimensions, vector< size_t > &sdims, size_t &numts)
 
- Static Public Member Functions inherited from VetsUtil::MyBase
static void SetErrMsg (const char *format,...)
 Record a formatted error message. More...
 
static void SetErrMsg (int errcode, const char *format,...)
 Record a formatted error message and an error code. More...
 
static const char * GetErrMsg ()
 
static void SetErrCode (int err_code)
 Record an error code. More...
 
static int GetErrCode ()
 Retrieve the current error code. More...
 
static void SetErrMsgCB (ErrMsgCB_T cb)
 
static ErrMsgCB_T GetErrMsgCB ()
 
static void SetErrMsgFilePtr (FILE *fp)
 
static const FILE * SetErrMsgFilePtr ()
 
static void SetDiagMsg (const char *format,...)
 Record a formatted diagnostic message. More...
 
static const char * GetDiagMsg ()
 
static void SetDiagMsgCB (DiagMsgCB_T cb)
 
static DiagMsgCB_T GetDiagMsgCB ()
 
static void SetDiagMsgFilePtr (FILE *fp)
 
static bool EnableErrMsg (bool enable)
 

Additional Inherited Members

- Static Public Attributes inherited from VetsUtil::MyBase
static char * ErrMsg
 
static int ErrCode
 
static int ErrMsgSize
 
static FILE * ErrMsgFilePtr
 
static ErrMsgCB_T ErrMsgCB
 
static char * DiagMsg
 
static int DiagMsgSize
 
static FILE * DiagMsgFilePtr
 
static DiagMsgCB_T DiagMsgCB
 
static bool Enabled
 
- Protected Member Functions inherited from VetsUtil::MyBase
void SetClassName (const string &name)
 

Detailed Description

Defines API for reading a collection of data.

Author
John Clyne
Date
January, 2015

The abstract Data Collection (DC) class defines an API for reading metadata and sampled data from a data collection. A data collection is a set of related data, most typically the discrete outputs from a single numerical simulation. The DC class is an abstract virtual class, providing a public API, but performing no actual storage operations. Derived implementations of the DC base class are required to support the API.

Variables in a DC may have 1, 2, or 3 spatial dimensions, and 0 or 1 temporal dimensions.

The DC is structured in the spirit of the "NetCDF Climate and Forecast (CF) Metadata Conventions", version 1.6, 5, December 2011. It supports only a subset of the CF functionality (e.g. there is no support for "Discrete Sampling Geometries"). Moreover, it is more restrictive than the CF in a number of areas. Particular items of note include:

This class inherits from VetsUtil::MyBase. Unless otherwise documented any method that returns an integer value is returning status. A negative value indicates failure. Error messages are logged via VetsUtil::MyBase::SetErrMsg(). Methods that return a boolean do not, unless otherwise documented, log an error message upon failure (return of false).

Parameters
level

Grid refinement level for multiresolution variables. Compressed variables in the DC, if they exist, have a multi-resolution representation: the sampling grid for multi-resolution variables is hierarchical, and the dimension lengths of adjacent levels in the hierarchy differ by a factor of two. The level parameter is used to select a particular depth of the hierarchy.

To provide maximum flexibility as well as compatibility with previous versions of the DC the interpretation of level is somewhat complex. Both positive and negative values may be used to specify the refinement level and have different interpretations.

For positive values of level, a value of 0 indicates the coarsest member of the grid hierarchy. A value of 1 indicates the next grid refinement after the coarsest, and so on. Using postive values the finest level in the hierarchy is given by GetNumRefLevels() - 1. Values of level that are greater than GetNumRefLevels() - 1 are treated as if they were equal to GetNumRefLevels() - 1.

For negative values of level a value of -1 indicates the variable's native grid resolution (the finest resolution available). A value of -2 indicates the next coarsest member in the hierarchy after the finest, and so on. Using negative values the coarsest available level in the hierarchy is given by negating the value returned by GetNumRefLevels(). Values of level that are less than the negation of GetNumRefLevels() are treated as if they were equal to the negation of the GetNumRefLevels() return value.

lodThe level-of-detail parameter, lod, selects the approximation level for a compressed variable. The lod parameter is similar to the level parameter in that it provides control over accuracy of a compressed variable. However, instead of selecting the grid resolution the lod parameter controls the compression factor by indexing into the cratios vector (see below). As with the level parameter, both positive and negative values may be used to index into cratios and different interpretations.

For positive values of lod, a value of 0 indicates the the first element of cratios, a value of 1 indicates the second element, and so on up to the size of the cratios vector (See DC::GetCRatios()).

For negative values of lod a value of -1 indexes the last element of cratios, a value of -2 indexes the second to last element, and so on. Using negative values the first element of cratios - the greatest compression rate - is indexed by negating the size of the cratios vector.

Parameters
cratiosA monotonically decreasing vector of compression ratios. Compressed variables in the DC are stored with a fixed, finite number of compression factors. The cratios vector is used to specify the available compression factors (ratios). A compression factor of 1 indicates no compression (1:1). A value of 2 indciates two to one compression (2:1), and so on. The minimum valid value of cratios is 1. The maximum value is determined by a number of factors and can be obtained using the CompressionInfo() method.
bsAn ordered list of block dimensions that specifies the block decomposition of the variable. The rank of bs may be less than that of a variable's array dimensions, in which case only the n fastest varying variable dimensions will be blocked, where n is the rank of bs. The ordering of the dimensions in bs is from fastest to slowest. A block is the basic unit of compression in the DC: variables are decomposed into blocks, and individual blocks are compressed independently.
wnameName of wavelet used for transforming compressed variables between wavelet and physical space. Valid values are "bior1.1", "bior1.3", "bior1.5", "bior2.2", "bior2.4", "bior2.6", "bior2.8", "bior3.1", "bior3.3", "bior3.5", "bior3.7", "bior3.9", "bior4.4"

Definition at line 150 of file DC.h.

Member Enumeration Documentation

External storage types for primitive data.

Enumerator
INVALID 
FLOAT 
DOUBLE 
INT32 
INT64 
TEXT 

Definition at line 155 of file DC.h.

Constructor & Destructor Documentation

VAPoR::DC::DC ( )
inline

Class constuctor

Definition at line 786 of file DC.h.

virtual VAPoR::DC::~DC ( )
inlinevirtual

Definition at line 787 of file DC.h.

Member Function Documentation

virtual int VAPoR::DC::CloseVariable ( )
pure virtual

Close the currently opened variable

Close the handle for variable opened with OpenVariableRead()

See also
OpenVariableRead()

Implemented in VAPoR::VDC, VAPoR::VDCNetCDF, and VAPoR::DCWRF.

virtual int VAPoR::DC::GetAtt ( string  varname,
string  attname,
vector< double > &  values 
) const
pure virtual

Read an attribute

This method reads an attribute from the DC. The attribute can either be "global", if varname is the empty string, or bound to a variable if varname indentifies a variable in the DC.

Parameters
[in]varnameThe name of the variable the attribute is bound to, or the empty string if the attribute is global
[in]attnameThe attributes name
[out]typeThe primitive data type storage format. This is the type that will be used to store the attribute on disk
[out]valuesA vector to contain the returned floating point attribute values
Return values
statusA negative int is returned on failure

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual int VAPoR::DC::GetAtt ( string  varname,
string  attname,
vector< long > &  values 
) const
pure virtual

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual int VAPoR::DC::GetAtt ( string  varname,
string  attname,
string &  values 
) const
pure virtual

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual std::vector<string> VAPoR::DC::GetAttNames ( string  varname) const
pure virtual

Return a list of available attribute's names

Returns a vector of all attribute names for the variable, varname. If varname is the empty string the names of all of the global attributes are returned. If varname is not defined an empty vector is returned.

Parameters
[in]varnameThe name of the variable to query, or the empty string if the names of global attributes are desired.
Return values
attnamesA vector of returned attribute names
See also
GetAtt()

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual XType VAPoR::DC::GetAttType ( string  varname,
string  attname 
) const
pure virtual

Return the external data type for an attribute

Returns the external storage type of the named variable attribute.

Parameters
[in]varnameThe name of the variable to query, or the empty string if the names of global attributes are desired.
[in]nameName of the attribute.
Return values
Ifan attribute named by name does not exist, a negative value is returned.

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual bool VAPoR::DC::GetBaseVarInfo ( string  varname,
DC::BaseVar var 
) const
pure virtual

Return metadata about a data or coordinate variable

If the variable varname is defined as either a data or coordinate variable its metadata will be returned in var.

Return values
boolIf the named variable cannot be found false is returned and the values of var are undefined.
See also
GetDataVarInfo(), GetCoordVarInfo()

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual bool VAPoR::DC::GetCoordVarInfo ( string  varname,
DC::CoordVar cvar 
) const
pure virtual

Return a coordinate variable's definition

Return a reference to a DC::CoordVar object describing the coordinate variable named by varname

Parameters
[in]varnameA string specifying the name of the coordinate variable.
[out]coordvarA CoordVar object containing the definition of the named variable.
Return values
boolFalse is returned if the named coordinate variable does not exist, and the contents of cvar will be undefined.

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual std::vector<string> VAPoR::DC::GetCoordVarNames ( ) const
pure virtual

Return a list of names for all of the defined coordinate variables.

Returns a list of names for all coordinate variables defined

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual std::vector<string> VAPoR::DC::GetCoordVarNames ( int  ndim,
bool  spatial 
) const
virtual

Return a list of coordinate variables with a given dimension rank

Returns a list of all coordinate variables defined having a dimension rank of ndim. If spatial is true, only the spatial dimension rank of the variable is compared against ndim

Parameters
[in]ndimRank of dimensions for comparision
[in]spatialOnly compare spatial dimensions against ndim
virtual int VAPoR::DC::GetCRatios ( string  varname,
vector< size_t > &  cratios 
) const
virtual

Return the compression ratio vector for the indicated variable

Return the compression ratio vector for the indicated variable. The vector returned contains an ordered list of available compression ratios for the variable named by variable. If the variable is not compressed, the cratios parameter will contain a single element, one.

Parameters
[in]varnameData or coordinate variable name.
[out]cratiosOrdered vector of compression ratios
Return values
statusA negative int is returned on failure
virtual bool VAPoR::DC::GetDataVarInfo ( string  varname,
DC::DataVar datavar 
) const
pure virtual

Return a data variable's definition

Return a reference to a DC::DataVar object describing the data variable named by varname

Parameters
[in]varnameA string specifying the name of the variable.
[out]datavarA DataVar object containing the definition of the named Data variable.
Return values
boolIf the named data variable cannot be found false is returned and the values of datavar are undefined.

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual std::vector<string> VAPoR::DC::GetDataVarNames ( ) const
pure virtual

Return a list of names for all of the defined data variables.

Returns a list of names for all data variables defined

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual std::vector<string> VAPoR::DC::GetDataVarNames ( int  ndim,
bool  spatial 
) const
virtual

Return a list of data variables with a given dimension rank

Returns a list of all data variables defined having a dimension rank of ndim. If spatial is true, only the spatial dimension rank of the variable is compared against ndim

Parameters
[in]ndimRank of dimensions for comparision
[in]spatialOnly compare spatial dimensions against ndim
virtual bool VAPoR::DC::GetDimension ( string  dimname,
DC::Dimension dimension 
) const
pure virtual

Return a dimensions's definition

This method returns the definition of the dimension named by dimname as a reference to a DC::Dimension object. If dimname is not defined as a dimension then the name of dimension will be the empty string()

Parameters
[in]dimnameA string specifying the name of the dimension.
[out]dimensionThe returned Dimension object reference
Return values
boolIf the named dimension can not be found false is returned.

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual bool VAPoR::DC::GetDimension ( string  dimname,
size_t &  length,
int &  axis 
) const
virtual

Return a dimensions's definition

This method returns the length and axis for the dimension named by dimname. If dimname is not defined as a dimension length and axis will both be set to zero, and false returned.

Parameters
[in]dimnameA string specifying the name of the dimension.
[out]lengthThe dimension length, which must be greater than zero.
[out]axisThe axis associated with the dimension.
Return values
boolIf the named dimension can not be found false is returned.
See also
DC::Dimension
virtual std::vector<string> VAPoR::DC::GetDimensionNames ( ) const
pure virtual

Return names of all defined dimensions

This method returns the list of names of all of the dimensions defined in the DC.

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual int VAPoR::DC::GetDimLensAtLevel ( string  varname,
int  level,
std::vector< size_t > &  dims_at_level,
std::vector< size_t > &  bs_at_level 
) const
pure virtual

Return a variable's dimension lengths at a specified refinement level

Compressed variables have a multi-resolution grid representation. This method returns the variable's ordered spatial and temporal dimension lengths, and block dimensions at the multiresolution refinement level specified by level.

If the variable named by varname is not compressed the variable's native dimensions are returned.

Parameters
[in]varnameData or coordinate variable name.
[in]levelSpecifies a member of a multi-resolution variable's grid hierarchy as described above.
[out]dims_at_levelAn ordered vector containing the variable's dimensions at the specified refinement level
[out]bs_at_levelAn ordered vector containing the variable's block dimensions at the specified refinement level
Return values
statusZero is returned upon success, otherwise -1.
See also
VAPoR::DC, DC::BaseVar::GetBS(), DC::BaseVar::GetDimensions()

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual int VAPoR::DC::GetMapProjection ( string  lonname,
string  latname,
string &  projstring 
) const
pure virtual

Return a Proj4 map projection string.

For georeference data sets that have map projections this method returns a properly formatted Proj4 projection string for mapping from geographic to cartographic coordinates. If no such projection exists an empty string is returned.

Parameters
[in]lonnameName of longitude coordinate variable
[in]latnameName of latitude coordinate variable
[out]projstringAn empty string if a Proj4 map projection is not available for the named coordinate pair, otherwise a properly formatted Proj4 projection string is returned.

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual int VAPoR::DC::GetMapProjection ( string  varname,
string &  projstring 
) const
virtual

Return a Proj4 map projection string for the named variable.

For georeference data sets that have map projections this method returns a properly formatted Proj4 projection string for mapping from geographic to cartographic coordinates. If no such projection exists for the named data variable an empty string is returned.

Parameters
[in]varnameName of a data variable
[out]projstringAn empty string if a Proj4 map projection is not available for the named coordinate pair, otherwise a properly formatted Proj4 projection string is returned.
virtual int VAPoR::DC::GetNumRefLevels ( string  varname) const
pure virtual

Return the number of refinement levels for the indicated variable

Compressed variables have a multi-resolution grid representation. This method returns the number of levels in the hiearchy. A value of one indicates that only the native resolution is available. A value of two indicates that two levels, the native plus the next coarsest are available, and so on.

Parameters
[in]varnameData or coordinate variable name.
Return values
numIf varname is unknown zero is returned. if varname is not compressed (has no multi-resolution representation) one is returned. Otherwise the total number of levels in the multi-resolution hierarchy are returned.

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual int VAPoR::DC::GetNumTimeSteps ( string  varname) const
virtual

Return the time dimension length for a variable

Returns the number of time steps (length of the time dimension) for which a variable is defined. If varname does not have a time coordinate 1 is returned. If varname is not defined as a variable a negative int is returned.

Parameters
[in]varnameA string specifying the name of the variable.
Return values
countThe length of the time dimension, or a negative int if varname is undefined.
See also
IsTimeVarying()
virtual int VAPoR::DC::GetVar ( string  varname,
int  level,
int  lod,
float *  data 
)
pure virtual

Read an entire variable in one call

This method reads and entire variable (all time steps, all grid points) from a DC. This is the simplest interface for reading data from a DC. If the variable is split across multiple files GetVar() ensures that the data are correctly gathered and assembled into memory Any variables currently opened with OpenVariableRead() are first closed. Thus variables need not be opened with OpenVariableRead() prior to calling GetVar();

It is an error to call this method in define mode

Parameters
[in]varnameName of the variable to write
[in]levelRefinement level of the variable. Ignored if the variable is not compressed.
[in]lodApproximation level of the variable. A value of -1 indicates the maximum approximation level defined for the DC. Ignored if the variable is not compressed.
[out]dataPointer to where data will be copied. It is the caller's responsbility to ensure data points to sufficient memory.
Return values
statusA negative int is returned on failure

Implemented in VAPoR::VDC, VAPoR::VDCNetCDF, and VAPoR::DCWRF.

virtual int VAPoR::DC::GetVar ( size_t  ts,
string  varname,
int  level,
int  lod,
float *  data 
)
pure virtual

Read an entire variable at a given time step in one call

This method reads and entire variable (all grid points) at time step ts from a DC. This is the simplest interface for reading data from a DC. Any variables currently opened with OpenVariableRead() are first closed. Thus variables need not be opened with OpenVariableRead() prior to calling GetVar();

It is an error to call this method in define mode

Parameters
[in]tsTime step of the variable to write. This is the integer offset into the variable's temporal dimension. If the variable does not have a temporal dimension ts is ignored.
[in]varnameName of the variable to write
[in]levelRefinement level of the variable. Ignored if the variable is not compressed.
[in]lodApproximation level of the variable. A value of -1 indicates the maximum approximation level defined for the DC. Ignored if the variable is not compressed.
[out]dataPointer to where data will be copied. It is the caller's responsbility to ensure data points to sufficient memory.
Return values
statusA negative int is returned on failure

Implemented in VAPoR::VDC, VAPoR::VDCNetCDF, and VAPoR::DCWRF.

virtual int VAPoR::DC::Initialize ( const vector< string > &  paths)
pure virtual

Initialize the DC class

Prepare a DC for reading. This method prepares the master DC file indicated by path for reading. The method should be called immediately after the constructor, before any other class methods. This method exists only because C++ constructors can not return error codes.

Parameters
[in]pathPath name of file that contains, or will contain, the DC master file for this data collection
Return values
statusA negative int is returned on failure

Implemented in VAPoR::DCWRF.

virtual bool VAPoR::DC::IsCompressed ( string  varname) const
virtual

Return a boolean indicating whether a variable is compressed

This method returns true if the variable named by varname is defined and it has a compressed representation. If either of these conditions is not true the method returns false.

Parameters
[in]varnameA string specifying the name of the variable.
Return values
boolReturns true if variable varname exists and is compressed
virtual bool VAPoR::DC::IsCoordVar ( string  varname) const
inlinevirtual

Return a boolean indicating whether a variable is a coordinate variable

This method returns true if a coordinate variable is defined with the name varname. Otherwise the method returns false.

Return values
boolReturns true if varname names a defined coordinate variable

Definition at line 1347 of file DC.h.

virtual bool VAPoR::DC::IsDataVar ( string  varname) const
inlinevirtual

Return a boolean indicating whether a variable is a data variable

This method returns true if a data variable is defined with the name varname. Otherwise the method returns false.

Return values
boolReturns true if varname names a defined data variable

Definition at line 1334 of file DC.h.

virtual bool VAPoR::DC::IsTimeVarying ( string  varname) const
virtual

Return a boolean indicating whether a variable is time varying

This method returns true if the variable named by varname is defined and it has a time axis dimension. If either of these conditions is not true the method returns false.

Parameters
[in]varnameA string specifying the name of the variable.
Return values
boolReturns true if variable varname exists and is time varying.
virtual int VAPoR::DC::OpenVariableRead ( size_t  ts,
string  varname,
int  level = 0,
int  lod = 0 
)
pure virtual

Open the named variable for reading

This method prepares a data or coordinate variable, indicated by a variable name and time step pair, for subsequent read operations by methods of this class. The value of the refinement levels parameter, level, indicates the resolution of the volume in the multiresolution hierarchy as described by GetDimLensAtLevel().

The level-of-detail parameter, lod, selects the approximation level. Valid values for lod are integers in the range 0..n-1, where n is returned by DC::BaseVar::GetCRatios().size(), or the value -1 may be used to select the best approximation available.

An error occurs, indicated by a negative return value, if the volume identified by the {varname, timestep, level, lod} tupple is not available. Note the availability of a volume can be tested with the VariableExists() method.

Parameters
[in]tsTime step of the variable to read. This is the integer offset into the variable's temporal dimension. If the variable does not have a temporal dimension ts is ignored.
[in]varnameName of the variable to read
[in]levelRefinement level of the variable. Ignored if the variable is not compressed.
[in]lodApproximation level of the variable. A value of -1 indicates the maximum approximation level defined for the DC. Ignored if the variable is not compressed.
Return values
statusReturns a non-negative value on success
See also
GetNumRefLevels(), DC::BaseVar::GetCRatios(), OpenVariableRead()

Implemented in VAPoR::VDC, VAPoR::VDCNetCDF, and VAPoR::DCWRF.

static bool VAPoR::DC::ParseDimensions ( const vector< DC::Dimension > &  dimensions,
vector< size_t > &  sdims,
size_t &  numts 
)
static

Parse a vector of DC::Dimensions into space and time dimensions

This is a convenience utility that parses an ordered vector of Dimensions into a vector of spatial lengths, and the number of time steps (if time varying). The dimension vector axis must be ordered: X, Y, Z, T

Parameters
[in]dimensionsAn ordered vector of dimensions
[out]sdimsOrdered vector of dimension lengths extracted from dimensions
[out]numtsThe number of time steps if dimensions contains a time dimension, otherwise numts will be one
Return values
statusA value of true is returned if the dimensions contains a correctly sized and ordered vector of dimensions
virtual int VAPoR::DC::Read ( float *  data)
pure virtual

Read all spatial values of the currently opened variable

This method reads, and decompresses as necessary, the contents of the currently opened variable into the array data. The number of values read into data is given by the product of the spatial dimensions of the open variable at the refinement level specified.

It is the caller's responsibility to ensure data points to adequate space.

Parameters
[out]dataAn array of data to be written
Return values
statusReturns a non-negative value on success
See also
OpenVariableRead()

Implemented in VAPoR::VDC, VAPoR::VDCNetCDF, and VAPoR::DCWRF.

virtual int VAPoR::DC::ReadRegion ( const vector< size_t > &  min,
const vector< size_t > &  max,
float *  region 
)
pure virtual

Read in and return a subregion from the currently opened variable

This method reads and returns a subset of variable data. The min and max vectors, whose dimensions must match the spatial rank of the currently opened variable, identify the minimum and maximum extents, in grid coordinates, of the subregion of interest. The minimum and maximum valid values of an element of min or max are 0 and n-1, respectively, where n is the length of the associated dimension at the opened refinement level.

The region returned is stored in the memory region pointed to by region. It is the caller's responsbility to ensure adequate space is available.

Parameters
[in]minMinimum region extents in grid coordinates
[in]maxMaximum region extents in grid coordinates
[out]regionThe requested volume subregion
Return values
statusReturns a non-negative value on success
See also
OpenVariableRead(), GetDimension(), GetDimensionNames()

Implemented in VAPoR::VDC, and VAPoR::DCWRF.

virtual int VAPoR::DC::ReadRegionBlock ( const vector< size_t > &  min,
const vector< size_t > &  max,
float *  region 
)
pure virtual

Read in and return a blocked subregion from the currently opened variable.

This method is identical to ReadRegion() with the exceptions that for compressed variables:

  • The vectors start and count must be aligned with the underlying storage block of the variable. See DC::SetCompressionBlock()
  • The hyperslab copied to region will preserve its underlying storage blocking (the data will not be contiguous)

Implemented in VAPoR::VDC, VAPoR::VDCNetCDF, and VAPoR::DCWRF.

virtual int VAPoR::DC::ReadSlice ( float *  slice)
pure virtual

Read a single slice of data from the currently opened variable

Decompress, as necessary, and read a single slice (2D array) of data from the variable indicated by the most recent call to OpenVariableRead(). The dimensions of a slices are NX by NY, where NX is the dimension of the array along the fastest varying spatial dimension, specified in grid points, and NY is the length of the second fastest varying dimension at the currently opened grid refinement level. See OpenVariableRead().

This method should be called exactly NZ times for each opened variable, where NZ is the dimension of third, and slowest varying dimension. In the case of a 2D variable, NZ is 1.

It is the caller's responsibility to ensure slice points to adequate space.

Parameters
[out]sliceA 2D slice of data
Return values
statusReturns a non-negative value on success
See also
OpenVariableRead()

Implemented in VAPoR::VDC, VAPoR::VDCNetCDF, and VAPoR::DCWRF.

virtual bool VAPoR::DC::VariableExists ( size_t  ts,
string  varname,
int  reflevel = 0,
int  lod = 0 
) const
pure virtual

Returns true if indicated data volume is available

Returns true if the variable identified by the timestep, variable name, refinement level, and level-of-detail is present in the data set. Returns false if the variable is not available.

Parameters
[in]tsA valid time step between 0 and GetNumTimesteps()-1
[in]varnameA valid variable name
[in]reflevelRefinement level requested.
[in]lodCompression level of detail requested. refinement level contained in the DC.

Implemented in VAPoR::VDC, VAPoR::VDCNetCDF, and VAPoR::DCWRF.


The documentation for this class was generated from the following file: