What do the different classification of a crime mean?

Within each category, there are three crime levels: felony, misdemeanor and petty offense. To further confuse matters, each level is broken down into classifications. At the felony level, there are six classifications, a class 1 felony being most serious and class 6 felony being the least serious. Likewise, the misdemeanor level has different classifications, but in this case there are only three. Again, a class 1 is worse than a class 3. Finally, the petty offense level has only two classifications, with 1 being the most severe.