Agree that these are good ideas....I suppose the question for me has always been less of how do I make this and more of how do I design an interesting desert map? I've looked at lots of desert maps (i'm particularly drawn to the Gobi in Mongolia and this one in Ethiopia), and what makes them interesting is that there are pockets of life (water, vegetation, etc) interspersed within the expanse of essentially flat sand. You also find some interesting variation in elevation as these barren mountainous areas seem to come out of nowhere and break up the monotony.

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What i've struggled to find is a concise explanation for why these terrains take their shape (i.e. where do I put oasis, rivers, mountains, scrub, etc.) Since, I'm currently running an Al-Qadim-type campaign, I'd really like to have a good, interesting regional map...and I suppose I've been hesitant to start working on it until I understand this stuff better.