m

yz = Flatten[
   Table[{0.1 i, 0.1 j,
     Log[Length[
        Select[YZ, ((0.1 i - 0.05 < #[[1]] <
              0.1 i + 0.05) && (0.1 j - 0.05 < #[[2]] <
              0.1 j + 0.05)) &]] + 1]}, {i, -10, 10}, {j, -10, 10}],
   1];