text: """
  World Projections
  -----------------
  This example shows a map of the countries of the world using four available
  geographic projections. For more details on the projections available in
  Altair, see https://vega.github.io/vega-lite/docs/projection.html
  """
  # category: maps
  import altair as alt
  from vega_datasets import data
  
  source = alt.topo_feature(data.world_110m.url, 'countries')
  
  base = alt.Chart(source).mark_geoshape(
      fill='#666666',
      stroke='white'
  ).properties(
      width=300,
      height=180
  )
  
  projections = ['equirectangular', 'mercator', 'orthographic', 'gnomonic']
  charts = [base.project(proj).properties(title=proj)
            for proj in projections]
  
  alt.concat(*charts, columns=2)
  