Ggplot

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New geoms, scales and aesthetics

* stat_step and geom_step to draw staircase plots (like plot(type="s"))

* order aesthetic (currently only for lines/paths) allows you to control the
drawing order within a group

* scale_manual makes it easier to let ggplot uses the exact
colours/sizes/linetypes that you want

* scale_reverse allows you to reverse the scale of x and y axes

* scale_grey is a new black and white scale for categorical data (colour and
fill)


Improved options handling

* new function opts() to allow modification of plot options by addition

* update(p, theme_bw) and p + theme_bw now work

These changes mean that you can modify plot options in the same way that you modify all other aspects of the plot, e.g. qplot(mpg, wt, data=mptcars) + opts(title = "Fuel economy vs weight")

Improved documentation

* many tweaks to the online documentation, particular including the actual
code you need to run for each object!

* every page now has a link to a form where you can submit feedback on exactly
you do or don't like about a page

* required aesthetics now listed in documentation

* geom_polygon now has a decent example

* numerous minor corrections suggested by Jörg Beyer

* separated plotting advice from details of plot construction (what vs how),
thanks to Bert Gunter for this suggestion


Improved map projections (with coord_map)

* coord_map defaults to orientation = c(90, 0, mean(range(y))) - this ensures
that multiple layers line up correctly, but means you will have to specify
the orientation yourself for many projections

* coord_map now respects limits set by scales

* removed useless ticks from coord_map

If you're using ggplot to draw maps and have thought of other features that would make your life easier, please let me know.


Bug fixes

* adding data and aesthetics in separate steps should now work

* layers with set parameters will not use mapped aesthetics

* use LazyLoad: false instead of SaveData: true for better future
compatability

* coord_cartesian: fixed bug that prevented you from overriding the default
axis expansion

* coord_equal: now scales correctly if ratio < 1

* geom_abline: fix bug where slope was ignored

* geom_jitter now works correctly with groups and categorical values (was
actually a bug in how scale_discrete deals with continuous values)

* geom_path: automatically switch between polylineGrob and segmentsGrob when
drawing paths so that setting line type now works properly

* geom_segment now uses both ends of segments to calculate axis limits

* plotmatrix: fix bug in scatterplot matrix where all scatterplots were
transposed!

* qplot: should now work better within functions

* quickplot added as an alias of qplot, to avoid confusion with qunif, etc

* scale_*: better error message if you add a scale without a matching
aesthetic mapping in the plot

* scale_identity no longer converts everything to character

* scale_identity: grob argument renamed to guide

* stat_*: made all statistics more robust to errors

* stat_quantile: fixed bug when only drawing a single quantile

* stat_smooth: returns silently if <2 non-missing data points


Minor aesthetic improvements

* coord_polar now specifies aspect.ratio by default, and I've made a few other
tweaks to make polar coordinates plot look nicer

* geom_bar no longer draws gray borders by default, but instead uses the same
colour as fill (this eliminates a tiny gap between neighbouring bars)

* plotmatrix: tweaks to improve display of scatterplot matrix

* scale_brewer: added option to reverse palette

* scale_colour: colour and fill legends now look exactly the same (previously
colour was missing a grey border)

* scale_discrete has slightly larger expansion (0.75 vs 0.5)

* stat_bar: only output bars with > 0 count

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Improved error messages and other notifications:

* all geoms and position adjustments should now give an informative error
message when required aesthetics are missing

* better error messages if data not a data frame, or mapping not created by
aes or aes_string

* better errors for qplot when variables missing or data invalid

* better error if somehow you are missing necessary scales

* stat_bin informs you of the default choice of binwidth

* stat_smooth gives helpful error messages for common problems

* printing a geom now displays the data set that it uses (if not the default)

Other improvements:

* colour and fill legends now surround by background plot colour

* can now draw arrow heads with geom_segment, and have added an example
demonstrating drawing a vector field

* density plots should always include 0 on y axis

* default boxplot outlier changed colour to black

* stat_smooth supports categorical variables a little better

* implemented hash methods for all ggplot objects. This is the first step in
making it easier for me to compare all examples between versions for quality
control purposes

New data:

* seals, contributed by David Brillinger and Charlotte Wickham, used for
vector field example

Bug fixes:

* geoms hline, vline and abline now all work correctly when a grouping variable is used

* block histograms (where individuals are identifiable) now work correctly

* all ggplot objects should now print properly from the command line

* fixed bug in geom_path when only 1 point

* segments geom now works correctly for more coordinate systems

* order variables in scatterplot matrix by order of variables in data.frame

* geom_density deals with missing values correctly when displaying scaled densities

* fixed bug in calculating categorical ranges

* fixed bug in drawing error bars

Subtractions

* now relies on R 2.6

* removed grid.gedit and grid.gremove, and code replaced by grid.ls

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Improvements:

* ggplot now gives rather more helpful errors if you have misspecified a
variable name in the aesthetic mapping

* changed default hline and vline intercepts to 0

* added "count" output variable from stat_density for creating
stacked/conditional density plots

* added parameters to geom_boxplot to control appearance of outlying points

* overriding aesthetics with fixed values that have already been set with
aesthetics now actually works

* slightly better names for xaxis and yaxis grobs

* added aes_string function to make it easier to construction aesthetic
mapping specifications in functions

* continuous scales now have labels argument so that you can manually specify
labels if desired

* stat_density now calculates densities on a common grid across groups. This
means that position_fill and position_stack now work properly

* if numeric, legend labels right aligned

* polar coordinates much improved, and with better examples

Documentation:

* fixed argument documentation for qplot

* added (very) rudimentary documentation about what functions return

* documentation now lists extra variables created by statistics

Bug fixes:

* coord_flip now works with segment and all interval geoms

* geom_errorbar now works in all coordinate systems

* derived y axes (eg. on histogram) are now labelled correctly

* fixed bug in stat_quantile caused by new output format from predict.rq

* fixed bug if x or y are constant

* fixed bug in histogram where sometimes lowest bar was omitted

* fixed bug in stat_qq which prevent setting aesthetics

* fixed bug in qplot(..., geom="density", position="identity")

* fixed stat_qq so that unnecessary arguments are no longer passed to the
distribution function

Subtractions:

* removed grid argument from ggsave, replaced by ggtheme(theme_bw)

* removed add argument from qplot

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* border now drawn on top of geoms, instead of below - this results in better
appearance when adjusting scale limits

* ggplot() + aes() now modifies existing default aesthetic mapping, rather
than overwriting

* polish examples in facet_grid

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* added experimental scatterplot matrix, see ?plotmatrix

* added new border.colour and grid.minor.colour options for better control
over plot apperance

* updated theme_bw to do better when drawing a plot with white background

* better default colour choices for gradients (and more discussion in examples)

* fixed bug in ScaleGradient2 where scales with different positive and
negative ranges were not scaled correctly

* allow expressions as result from strip.text

* fixed rare bug in geom_vline and geom_hline

* fixed example in geom_abline

* tweaked display of multiline axis labels

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* add argument to position dodge so it's now possible to accurately dodge things with different widths to their physical widths

* added median summary

New examples:

* logistic regression example in stat_smooth

Bugs fixed:

* evaluation of arguments to layer is no longer delayed

* can use categorical xseq with stat_smooth

* x and y axes named incorrectly (thanks to Dieter Menne for spotting this)

* can now pass position objects to qplot

* y jitter calculated correctly, and jittered data rescales axis now

* removed silly legend from quantile plot

* extra arguments not being passed on to geoms/stats

* fixed bug in stat_summary when summarising a factor

* fixed bugs in stat_summary, geom_ribbon, and coord_trans examples