i still haven't figured out what to do about blending ground textures at map square edges. i may just leave it unblended. i've actually seen that effect put to good use in tiger woods 2013 online (PS3 version). in the unreleased CAVEMAN version 2.0, i wrote a realtime 10 channel weighted texture blender. but that just made textures change uniformly as you moved from one map square center to the next.
the world is divided into 5x5 mile "map squares". each map square can have its own type of vegetation coverage (sand, dirt, prairie, tall grass, savanna, woods, or jungle). the coverage determines the ground texture map(s) used. this shot shows the corner where 4 map squares meet. The camera is located in woods, tall grass is ahead to the left and right, and dirt terrain is straight ahead.