         columns = d3.keys(data[0]).filter(
             (d)-> if d isnt '' and d isnt 'iso3' then d else null).sort()
 
+    # Expose update method.
     geomap.update = ()->
         update()
 

            .append('title')
                .text((d)-> d.properties.name + ': ' + format(iso_val(d.id)))

    draw = (selection)->
        svg = selection.append('svg')
            .attr('width', width)

            .attr('transform', 'translate(' + width / 2 + ',' + height / 2 + ')scale(' + k + ')translate(' + -x + ',' + -y + ')')
            .style('stroke-width', 1 / k + 'px')

    # Calculate data mapping, draw and colorize countries.
    update = ()->
        # Create mapping of iso3 to data selected value and set min and max.
        min = null
