Another commit related to timezones... The Unix date always being in UTC, this has been fixed. The resampling was not using dates in a proper way, this has been fixed. The GSN plugin has also been fixed, it now rounds time to the closest minute (in order to be consistent with our advertised "1 minute time resolution"). A rounding method has been implemented for dates.

The timezone parameter in io.ini is now named TIME_ZONE instead of TZ for clarity. 

Undefined dates should now be fully handled (ie: also in arithmetic).

- Date.*: allow to handle undefined Dates (== 0. for now), add new members undef, setUndef(), isUndef(), and rndJulianDate()
- IOUtils.*: replaced TZ with time_zone and TIME_ZONE
- ImisIO.*: correct typo seperateDrift to separateDrift

The full support for timezones has been brought back. This fixes issue 71. The SMET, SMET, IMIS, BORMA plugins have been validated. Geotop should be validtaed if an input data set is available. A new class will have to be implemented to represent time periods. This is currently only a typedef pointing to the Date class, but a specific class would be welcomed.

GSN has been fixed for some changes on the web service, but does not retrieve the correct timestamps (is this a GSN issue?). The GSN compilation has been improved: the warnings related to GSOAP have been removed. 

A new long wave radiaiton model using cloudiness as input has been added (Omstedt, 1990). 

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TO DO: write XML file from data

Quickfix for a complex issue: When requesting a resampled value, we try to (in accord with user configuration) read data ahead of the point to resample and data after that point. The start_date of that interval might not itself be a part of the buffer, although for the rest of the interval there is plenty of data. Currently this situation would lead to an empty result set. With the quickfix the interval will not have to encompass that first element start_date necessarily. 

Two other possible solutions: change IOUtils::seek or the interval that BufferedIOHandler has in its buffer (prebuffer more elements)

The min and max filters have been implemented. The "how to write a filter" documentation page has been updated to relfect the latest changes. The operator << has been implemented for various objects involved in the data processing.

Refreshing the includes in MeteoIO.h and paving the way for the popc version (that still has to be done for IOManager).

The (advanced) configuration of the BufferedIOHandler through io.ini (General section) has been added. It currently introduces two keywords (BUFF_CHUNKS_SIZE and BUFF_CHUNKS) to drive how much data to read at once and how much data to buffer. Currently, their product is directly used in the read, thus not reading anything by chunks smaller than a full buffer.

Fixed some << outputs, two compilation warnings found on Hera as well as introduced.

Added comments to the IOManager and a sanity check to the setProcessingLevel(unsigned int) function.

Finalization of the new filtering infrastructure: speed optimizations (IOManager, MeteoProcessor), clean up

The necessary wrapping code has been added, so that the user can dynamically specify which regression model to use. This might have to be done differently in the future, so that sensible initial guess could be associated with each model.

The least square fit now works. It still needs some polishing (to dynamically change the fit model), but the core works.

A new way of calling Matrix::solve has been added (writing the result into a given matrix instead of allocating a new one).

A missing include in MeteoIO.h has been added.

A new version of the CosmoXMLIO plugin is also part of this commit, with some necessary fixes in the CMakeLists

TO DO:
Implement humidity from Dew Point
Add Max Wind Speed?
Check if we have data from Grid Point or Real Station Location

The user can now freely configure how big the resampling window should be. Simply add a WINDOW_SIZE key to the [Interpolations1D] section:

[Interpolations1D]
WINDOW_SIZE = 20000 #20000seconds

Fixed a bug in the IOManager: before resampling data we simply read it through the getMeteoData function of the IOManager.

[Filters]
RH::filter1 = rate
RH::arg1 = 0.01

The MeteoFilter object is obsolete, it has been fully replaced with the ProcessingStack class. Added comments to MeteoProcessor.h

Further improvements to the new filtering infrastructure: windowed filters now inherit from the class WindowedFilter, giving them an easy handle on getting the correct window for every data point. FilterMedianAvg and FilterMeanAvg now fully implemented (soft/not soft, left/center/right windowing). Sample io.ini:

[Filters]
TA::filter1     = mean_avg
TA::arg1        = soft right 5 3600
TA::filter2     = min_max
TA::arg2        = soft 282 286 280 290

RH::filter1     = median_avg
RH::arg1        = center 8 3600

A new group of classes has been created, under the meteolaws subdirectory. This contains various general meteorological laws, such as a sun radiation model, standard atmosphere, etc

The first implementation (not tested yet) of a non-linear least square fit algorithm has been implemented in the libfit1D. 

Several documentation issues have been fixed (obsolete code examples, etc) and classes grouped by modules. This should help the user to quickly locate the classes of interest. 

A new setAltitude() method has been added to Coords in order to be able to manually build stations from grided data and dem. A bug in Grid2DObject has been found that was reseting i,j,k to nodata when doing a gridify with i,j,k known. Better date parsing abilities have been implemented in IOUtils so that purely numerical dates as generated with the date format NUM can be parsed if *part* of a string in a meanigful way (useful for recovering dates from file names). 

A small Timer class has been added for easy code timing. This was in Alpine3D and had been imported from popc (with their agreement) and now quite heavily reworked.

New filter system rolled out with currently two filters up and running: min_max and mean_avg (without the soft option, only left or right centering). The new filter system is built upon processing blocks that take a vector<MeteoData> as input and return a processed vector<MeteoData>. The individual filters are stacked in a ProcessingStack where they are invoked sequentially.

The definition of the "<<" operator has been written for IOManager and made more consistent for others

The documentation has been updated (structure diagram, missing key in ImisIO) as well as the code examples so that they use the latest changes.

Added functionality to the Meteo2DInterpolator: it is now possible to access the iomanager and hence to access historical data points from within any spatial interpolation.

The IOManager has been expanded to:
1) cache already filtered data points and
2) provide a getAvgSamplingRate() function that returns the average data points seen per day.

Introducing the new IOManager - the user interface to meteoio. This version is fully backwards compatible, but does not incorporate all features of the BufferedIOHandler: the grid reading and writing are currently not supported by this IOManager.

Some more cleanup in the Matrix class: there is a transpose in place operator (that actually does an internal copy), a few bugs in constructors got fixed. The matrix code example now works with this version.

Fixed some warnings, added a copy constructor to the Matrix class, changed the methods names so that a method that does NOT change the matrix itself is called "getXXX', like "getInv" compared to "inv" that inverses the matrix in place.

The solve method for AX=B now works with A square matrix, X and B rectangular matrix. Better efforts are done to avoid divisions by zero. Better documentation. A new method has appeared to fill a matrix with random numbers.