changes

计算线性趋势 回归系数 主要用于气象站点值的线性趋势计算

g2lib-1.0   - August 2003 - Original version

g2lib-1.0.1 - October 2003 - Added support for Grid Definition Template 3.31
                             Albers Equal Area.
                           - Added new parameters to the Parameter list in
                             params.f
                           - Minor documentation updates.

g2lib-1.0.2 - February 2004 - Added new parameters in params.f for use with 
                              Quickscat data and Ozone (Air Quality)

g2lib-1.0.3 - May 2004 - Changed most PDT templates in module pdstemplates to 
                         allow negative surface values.
                       - Added new routine to gridtemplates and pdstemplates 
                         modules to return number of entries in a specified 
                         template.
                       - Added New routines, getgb2p getgb2rp, used to request 
                         a packed GRIB2 message from a file.
                       - New module g2grids can be used to return GDT entries 
                         for a specific grid from a file containing a list of
                         predefined grids.

g2lib-1.0.4 - August 2004 - Added functionality to support encoding of 
                            "Missing" data values within the data field when
                            using Data Representation Templates 5.2 
                            (complex packing) and 5.3 (complex packing and 
                            spatial differencing).  See octets 23 - 31 in DRTs
                            5.2 and 5.3 for more info on missing value
                            management.
                          - Increased the packing efficiency of Data 
                            Representation Templates 5.2 and 5.3 by adding 
                            MDL/Glahn algorithm for determining effective
                            groupings.

g2lib-1.0.5 - December 2004 - WMO approved the JPEG2000 and PNG Data 
                             Representation Templates ( 5.40000 and 5.40010,
                             respectively ) for operational use.  The templates
                             were assigned WMO values of 5.40 and 5.41, 
                             respectively.  Changes were made to the source to 
                             recognize either template number.
                           - Fixed bug encountered when packing a near constant
                             field with DRT 5.40 or 5.40000 (JPEG2000).
                           - Added consistency check, provided by 
                             Arthur Taylor/MDL, used when unpacking Data 
                             Templates 7.2 and 7.3.
                           - Corrected the documentation for subroutine
                             addfield in the grib2.doc file.  Incorrect
                             arguments were specified for this routine.
                           - Corrected bug when packing Secondary missing
                             values in Data Representation Templates 5.2 and
                             5.3.

g2lib-1.0.6 - April 2005 - Modified the way GETGB2 manages the GRIB2 file 
                           indexes, so that it can be more efficient and
                           flexible when reading from multiple
                           GRIB2 files.
                         - Fixed bug in PUTGB2 that caused data fields to be
                           encoded incorrectly.
                         - Added routine gdt2gds that converts grid information
                           from a GRIB2 Grid Description Section (GDS) and
                           Grid Definition Template to GRIB1 GDS info.

g2lib-1.0.7 - April 2005 - Fixed bug causing seg fault when using JPEG2000 
                           encoding algorithm on a grid with an insanely large
                           number of data points bitmapped out.

gslib-1.0.7.1 - December 2006
			- Added new local parameter conversion entries