## Changes in Version 3.1
Thanks to Johannes Menzel for bug reporting, Thanks to Jan (jmablans) for bug reporting, 
Thanks to Earo Wang for speedup of plotNA.gapsize,
Special Thanks to Sebastian Gatscha for plotting functions, new na_mean options, new unit tests

* Plotting functions are all in ggplot now (way better looking). Additionally they got renamed accordingly ggplot_na_distribution, ggplot_na_intervals, ggplot_na_gapsize, ggplot_na_imputations.

* Speedup for plotNA_gapsize calculation (now renamed ggplot_na_gapsize)  (thx to Earo Wang) 

* Renamed plotting functions to plotNA_distribution, plotNA_distributionBar, 
  plotNA_imputations, plotNA_gapsize
  
* Added harmonic and geometric mean as option for na_mean

* Removed bug in na_replace - it can now be used with all NA vectors since 
 it requires no minimum of non-NA values (reported by Jan - jmablans)
 
* Improved na.random input check (usable with all NA input now if upper and lower bound
  paramters are exlicitly set to numeric values)

* Additional unit tests for the plotting functions

* Additional unit tests for the all imputation functions (testing all NA input)

* Update for testthat unit tests

* Fixed a mistake in README.md (reported by Johannes Menzel)

* Added to statsNA: Number of Gaps, Average Gap Size + reformatting of code + 
  compatibility with other ts objects

* Documentation improvements through newer roxygen version (Markup now possible in documentation)

* updated Readme + Vignette to new function names

* Added the imputeTS Cheat Sheet as Vignette

* Added new vignette Gallery Missing Data Visualizations

* Added revdep

## Changes in Version 3.0

Thanks to Jim Maas, shreydesai, Breza, CameronNemo for reporting bugs
Thanks to  Sebastian Gatscha providing the (way faster) C++ na.ma() implementation

 * tibble and tstibble compatibility
 
 * Reworked internal code documentation

 * na.ma speed up via C++ 

 * Changed vignette builder to R.rsp

 * Used R package styler package to optimize source code readability
 
 * Made some changes to better follow tidyverse style guide
 
 * Replaced na. with na_ e.g na.mean with na_mean usw.This fits better to modern code
   style guidelines. The old function names will still work for a while,
   but give a warning.

 * Added findFrequency option to na.seadec and na.seasplit

 * Added maxgap option
 
 * Fixed bug for na.seadec - also imputed known values in some special cases
   (reported by CameronNemo)

 * Added doi: 10.32614/RJ-2017-009 to describtion, references, readme and citation file

 * Added StackExchange link to Readme

 * Moved stinepack from imports to suggested
 
 * Internal reorganization of imports - now always using pkg::function and importFrom pkg x1 x2 x3instead of just import pkg

* Fixed bug in na.ma when using xts time series with NA at the end

* Fixed error message in na.interpolation if wrong parameter is given       
   stop("Wrong parameter 'option' given. Value must be either 'linear', 'spline' or 'stine'.")
   (reported by Breza)

* Fixed spelling mistakes in na.seadec and na.seasplit (reported by shreydesai)

* Fixed bug with na.random() output (reported by Jim Maas)

## Outlook - Planned for Version 3.1

 * Better plots using ggplot2
 
 * Better and more unit tests 
 
 * Additional vignettes
 
 * Adding harmonic and geometric mean as option for na_mean


## Changes in Version 2.7

  * Updated Description: Orcid Id added, packages required for unit test add as "Suggested"

  * Small correction in README.md, small update to citation file
  
  * Replaced NEWS with NEWS.md for better formatting
  

## Changes in Version 2.6

  * Updated citation file
  
  * Minor changes to vignette


## Changes in Version 2.5

  * Adjusted unit test to a update of forecast package
  


## Changes in Version 2.4

  * Small speed improvments for na.kalman
  
  * Improved input check for all functions

  * Bugfix for unit tests 

  * Changes to unit test (because of zoo update)
  

## Changes in Version 2.3

  * Bugfix for na.kalman with integer input
  
  * Readme Update

  * Improved error messages for na.seasplit and na.seadec

  * Minor vignette changes


## Changes in Version 2.2

  * Bugfix for na.locf (also concerned na.kalman) 
  

## Changes in Version 2.1

  * Fixed for problems with Solaris/Sparc
  
  * Fixes for problems with vignette on osx


## Changes in Version 2.0

  * Bugfix for plots without missing data
  
  * Increased performance for na.locf
  
  * Minor bugfixes for specific data.frame inputs
  
  * Minor bugfixes for specific xts object inputs

  * Improved Code Documentation
  
  * Added new software tests


## Changes in Version 1.9

  * Added Vignette


## Changes in Version 1.8

  * Computation time improvments for na.locf (up to 10000 times faster)
  
  * Computation time improvments for na.interpolation (up to 10000 times faster)
  
  * Computation time improvments for na.kalman (only slightly faster, under 10%)
  
  * Fixed unnecessary warning message with some na.kalman options
  
  * Adjusted default parameters for plotNA.distributionBar (using nclass.Sturges for breaks parameter)
  
  * Fixed issue with too sensitive input checking
  

## Changes in Version 1.7
  
  * Enabled usage of multivariate input (data.frame, mts, matrix,...) for all imputation 
    functions except na.remove. This means users do not have to loop through all columns 
    by themselfes anymore if they want to use the package with multivariate data. The
    imputation itself is still performend in univariate manner (column after column). 
  
  * Improved compatibility with different advanced time series objects like zoo and xts.
    Using the imputation functions with these time series objects should be possible now. 
    These series will not be explicitly named as possible input in the user documentation.
    Absence of errors can not be guaranteed. However, there are no known issues yet.
  
  * Added several things for unit tests with pkg 'testthat'
  
  * Added unit tests for every function
  
  * Adjusted error messages
  
  * Internal Coding style improvement: replaced all T with TRUE and all F with FALSE
  
  * Adjustment tsHeating / tsHeatingComplete datasets (set 1440 as frequency parameter)
  
  * Adjustment tsNH4 / tsNH4Complete datasets (set 144 as frequency parameter)
  
  * Fixes for grammar, spelling and citations in the whole documentation
  
  * Revised examples in the documentation for all functions
 
  * Restricted output of na.remove to vector only (issue with incorrect time information otherwise)
  
  * Added better x-axes labels for plotNA.distribution
  

## Changes in Version 1.6
  
  * Added github links to description file
  
  * Added citation file
  
  * Updated Readme (badges for travis ci and cran status)
  
  * Fix in documentation for na.interpolation 
   (due to outdated descriptions)
   
  * Fix in documentation plotNA.distribution / plotNA.distributionBar
    (due to interchanged descriptions)
    
  * Added references to used packages in na.kalman and na.interpolation documentation


## Changes in Version 1.5

  * Allows now also numeric vectors as input

  * Removed na.identifier parameter for all functions (too error prone, better handled 
    individually by the user)

  * Minor changes in na.interpolation with option = "stine"
  
  * Added na.ma imputation function

  * Replaced "data" in all function parameters with the more common "x"

  * Improvement of all code examples

  * Renamed heating/heatingComplete dataset to tsHeating/tsHeatingComplete

  * Renamed nh4/nh4Complete dataset to tsNH4/tsNH4Complete

  * Added tsAirgap / tsAirgapComplete datasets

  * Improved imputeTS-package documentation

  * Added na.kalman imputation function

  * Added README.md function

  * Added statsNA function

  * Added plotNA.gapsize function
  
  * Renamed vis.imputations to plotNA.imputations

  * Renamed vis.barMissing to plotNA.distributionBar

  * Renamed vis.missing to plotNA.distribution
  
  * Fixed issues with parameter pass through and legend for
    all plotting functions
    
  * Improved dataset documentation 


## Changes in Version 0.4

  * Update of vis.differences (better looking plot now)
  
  * Added vis.missing to visualize the distribution of missing data in a time series
  
  * Added vis.barMissing, which is especially suited to visualize missing data in very huge time series
  
  * Update na.interpolate (added Stineman interpolation and enabled ... parameter 
    for all interpolation algorithms to pass through parameters to the underlying functions)


## Changes in Version 0.3

  * Added two datasets of sensor data
  
  * vis.differences for plotting differences between real and imputed values
  

## Changes in Version 0.2

  * Removed internal functions from visible package documentation

  * Added additional algorithms: na.seasplit and na.seadec
  
  * internal function for algorithm selection
  

## Changes in Version 0.1

  * Created initial version of imputeTS package for univariate time series imputation

  * added the simple imputation functions: na.locf, na.mean, na.random, na.interpolation, 
    na.replace

  * added na.remove function for removing all NAs from a time series
