Hello again.
I noticed, that on a whole number of maps, raw resources have a very high chance to be placed either directly at the western or at the northern border of the map, here's a screenshot of an example: http://i.imgur.com/6TYcmiC.jpg, notice the string of resources at the northern edge of the map and a smaller one at the western edge.
I reckon something in the algorithm placing raw resources (farms, clay pits, sawmills, mines, etc.) "likes" low numbers, cause the coordinates of all these places are either (1-4, XXX) or (XXX, 1-4).