Unclassed Choropleth

I was shocked by this unclassed choropleth map. The map shows how many acres are harvested for sale in the US. I always thought the middle of the country was farm country bu it does not look so green. However the areas in the middle of the coutry are broken in to much smaller segments which is on of the downfalls of this type of map because looks can sometimes be deceiving.

http://www.nass.usda.gov/research/atlas02/Crops/Vegetables%20and%20Melons%20Harvested/Vegetables,%20Acres%20Harvested%20for%20Sale-choropleth%20map.gif