'tissot_map()' will add the [world] coastline to any map.
tissot_map(..., add = TRUE) tissot_abline(lambda, phi = NULL, ..., proj.in = NULL) tissot_get_proj()
| ... | graphical parameters for [lines()] if 'add = TRUE', or for [plot()] if 'add = FALSE' |
|---|---|
| add | logical, default 'TRUE' add to existing plot or create new |
| lambda | longitude at which to draw a vertical line |
| phi | latitude at which to draw a horizontal line |
| proj.in | projection for expert use |
'tissot_map()' returns the internal world map data (projected if one is current) as a matrix
'tissot_abline()' called for its side effect of drawing on the plot
'tissot_get_proj()' returns the value of the current projection, or NULL
'tissot_get_proj()' When the indicatrix is plotted it registers its projection. This string can be obtained with this getter function.
'tissot_abline()' will draw a vertical and horizontal line at a give longitude latitude (where they intersect is the actual lon,lat location)