Before laying out and opening any roadway, parkway or boulevard, the commission shall cause a survey to be made and a map thereof to be filed in its office, showing the termini of each roadway, parkway or boulevard, including the courses and distances, the names of the several owners or reputed owners of real estate through which the same will pass, so far as the same can be ascertained, and the streets or roads which may be included therein.
The commission shall not be obliged to disclose such locations, surveys or maps to public inspection until it has taken proceedings to condemn real estate or any right or interest therein necessary therefor.