Hi, I have created the branch style-functions to implement functions like mkgmap::length that can be used in the style system. The mkgmap::length function is the first one that has been implemented. It returns the length of a way in metre. For relations it returns the sum of way length of all members. The function can be used like a tag name: highway=* & access=private & mkgmap::length < 10 { delete highway } Calculations are cached. So the mkgmap::length is calculated not more than once per element. Known bugs: - Rules with a function must always contain a tag rule. Otherwise the optimizer disposes the rule. so the rule mkgmap::length < 10 { delete highway } will never be executed. - The length of relations does not always makes sense. E.g. the length of turn restrictions, multipolygons maybe should be not calculated. Steve: can you have a look on it and give your comment if the implementation looks good to you and what you dislike and what you want to change :-) Can you please also give a hint how I can tell the optimizer that functions should always be treated as an existing tag. Do you think it makes more sense to implement the functions as an additional operator? I am free to change the implementation completely :-) WanMil