attempt.js

$(window).resize(function(){
  width = $(this).width();
  map = $('div#map');
  imgWidth = $('div#map img').width();
  scale = width / imgWidth;
  transform = 'translateY(-'+10/scale+'%) translateX(-'+10/scale+'%) scale('+scale+')';
  map.css({
    'width' : (100/scale)+'%',
    '-webkit-transform' : transform,
    '-moz-transform' : transform,
    '-ms-transform' : transform,
    '-o-transform' : transform,
    'transform' : transform
  });
  console.log('div#map { width: %s%; transform: %s; }',(100/scale),transform);
});