Hi EoS, for some reason your posts are getting caught in the moderation queue. Might be the 'Sin' in your handle...I'm not sure. Hopefully you should be OK now.
As to your question we have an entire section of the site devoted to tutorials which cover most of the items you've listed (not sure about grass). Not sure also about what you mean by 'geography' tutorials. We are primarily concerned with drawing mountains, rivers etc on maps. Is that what you are after?