outline_earth reads Earth data from disk (see below) and generates outlines of the Earth continents, coast lines, countries and/or rivers (in combination or separately), at various resolution, with a user-specified color, linestyle and thickness, which can then be overplotted onto HEALPix maps using cartview, gnomview, mollview or orthview.
– If run under IDL (or if BEHAVIOR='IDL') the Earth data are read from $IDL_DIR/resource/maps/*/*.* with 'low' (HIRES=0) and if available 'high' (HIRES1) resolution.
– If run under GDL (or if BEHAVIOR='GDL') the GSHHS data (version 2.2 or more, available at https://www.ngdc.noaa.gov/mgg/shorelines/data/gshhg/latest/gshhg-bin-*.zip) are read from $GSHHS_DATA_DIR/*.b with HIRES=0,1,2,3,4 standing for 'coarse', 'low', 'intermediate', 'high' and 'full' resolution respectively.
In GDL mode, Coasts and Continents are degenerate.
– Under FL, BEHAVIOR must be set to either 'IDL' or 'GDL', and the corresponding data must be available .
geo = outline_earth(/continents,/hires,thick=0.8) |
geo = outline_earth(geo, /rivers, thick=0.1,col=20) |
mollview, findgen(12), $ |
outline=geo, /flip, coord=['C','C'], $ |
min=-11,max=11,colt='planck1',/crop |
Creates a structure containing a thick-lined high-resolution continent outline, adds a thin-lined lower resolution rivers outline, in a different color, and then overplots the combination on a Mollweide projection of a (simple) HEALPix map (see Fig. 6) Note that since Earth data (generated in Celestial = eQuatorial coordinates) are usually shown with the longitude increasing from left to right (contrary to astronomical data), the flip keyword must be set in mollview.
Version 3.82, 2022-07-28