How to obtain initial seeds?

[jiayily]

Not really understand the rule of picking ground seeds.

TRAVEL/include/travel/tgs.hpp

Lines 568 to 573 in ea9520a

	for(int i=0 ; i< (int) p_sorted.points.size() ; i++){
	if(p_sorted.points[i].z < lpr_height + TH_SEEDS_){
	if (p_sorted.points[i].z < lpr_height-TH_OUTLIER_) continue;
	init_seeds.points.push_back(p_sorted.points[i]);
	}
	}

The processing above calculates the mean z in a tri-grid node and pick points whose z belong to [mean_z-TH_OUTLIER_, mean_z+TH_SEEDS_). This may include many points from obstacles. Why not pick Lowest Points?