Barchart cash "contract"?

How accurately Barchart reflects the Spot Market prices?

For example Corn:
http://www2.barchart.com/dfutpage.asp?sym=C&code=BSTK&section=grains

 

Cash prices and basis vary greatly by physical location and destination. Check out the cash bids at serval elevators throughout the country.

 

Thanks. Certainly there are many physical grain qualities, good ones sold at a premium, poor ones at a discount.

So, Is Barchart cash price a good approximation of spot prices?

 

Not familiar with it but most likely it is for a major delivery point with multiple merchandisers so a good benchmark if it is.