function result = select_observations (observations, which)
%-------------------------------------------------------
% plots the vehicle and features, whose coordinates
% appear in features.x, with symbol.
%-------------------------------------------------------
global configuration;

[ix, iy ind] = obs_rows(which);
result.z = observations.z(ind);
result.R = observations.R(ind,ind);
result.m = length(which);
result.ground_id = observations.ground_id(which);