Autoplace settings for single patch in starting area

[BuilderOfAges]

I'm trying to create autoplace settings that will tend to make one patch of about 20 items of a resource in the starting area, and none outside it. I tried looking at the base resource prototypes and some other mods, but I haven't found anything that creates patches only in the starting area. So far the best I have come up with is this:

Code: Select all

sharpness = 15/16,
richness_multiplier = 1000,
coverage = 0.00000000001,
starting_area_size = 11,
starting_area_amount = 11,
peaks = {
	{
		noise_layer = "clay-patch",
		noise_octaves_difference = -0.85,
		noise_persistence = 0.4
	}
},

This usually makes a reasonable patch in the starting area, and few outside it. But sometimes the patch in the starting area is ridiculously rich, and there are always at least some patches outside the starting area.

Are there settings that will do what I want? Or should I just try to spawn the patches myself rather than let the autoplace mechanism do it?