tm_.
tm_shape that specifies the shape object, and also specifies the projection and bounding boxThe elements that serve as aesthetics layers are
tm_fill to fill the polygons
tm_borders to draw polygon borders
tm_polygons to draw polygons (it is a combination of tm_fill and tm_borders)
tm_bubbles to draw bubbles
tm_lines to draw lines
tm_text to add text annotations
tm_raster to draw a raster
The layers can be stacked by simply adding them with the + symbol. The combination of the elements described above form one group. Multiple groups can be stacked. Each group should start with tm_shape.
The attribute elements are
tm_grid to specify coordinate grid lines
tm_credits to add a credits/acknowledgements text label
tm_scale_bar to add a measurement scale bar
tm_compass to add a map compass
The element tm_facets specifies facets (small multiples). The element tm_layout is used to change the layout of the map.
vignette("tmap-nutshell")The examples in each of the element functions