cartogram 0.4.0

With the new n_cpu option in cartogram_cont() and cartogram_ncont(), the distortion can be calculated on multiple CPU cores.
The default value for the treshold option in cartogram_cont() will be automatically increased if the weighting variable contains a lot of zeros.
New testthat tests

cartogram 0.3.0

Remove sp, rgdal and maptools from examples and suggestions.
cartogram_cont() has a new parameter verbose = FALSE to hide print of size error on each iteration.

cartogram 0.2.2

Fix geometry replacement in cartogram_ncont

cartogram 0.2.0

Migrated all functions to sf, fixed problems with multipolygons.
cartogram functions won't accept features with longitude/latitude coordinates anymore.

cartogram 0.1.1

Update sf code. Thanks to @Nowosad for speeding things up!

cartogram 0.1.0

Non-Overlapping Circles Cartogram (Dorling)

cartogram 0.0.3

sf support added

cartogram 0.0.2

Non-contiguous Area Cartogram
Prepare data with missing or extreme values before cartogram calculation for faster convergence

cartogram 0.0.1

Initial Release