Elevation points of aerolaser scanning of the Estonian topography database

Estonian Topographic Database (ETAK) aerolaser scanning elevation points or LiDAR (Light Detection And Ranging) elevation points are elevation points collected as a result of aerolaser scanning. Approximately half of the points are points on the ground, the rest denote other objects (vegetation, buildings, water, etc.). The entire territory of Estonia is evenly covered by altitude points flown from a height of 2400 m, with an average density of 0.45 points per square metre. In densely populated areas, flights are conducted at an altitude of 1500 m, which gives an average dot density of 1.56 points per square metre. For aerial laser scanning (ALS) elevation points, the following shall be indicated: three-dimensional coordinates, class, intensity and type of reflection. Points accumulated at altitude 2400 m are automatically classified as: 1 - unclassified; 2 - Ground not included in Class 8; 7 - noise; 8 - ground depleted points (planned distance >20 or height range +/-0.3); 14 - the surface of larger bodies of water. In densely populated areas, at a flight altitude of 1500 m, class 6 - buildings is added. From 2012 onwards, the data are classified as follows: 1 - unclassified; 2 - Ground not included in Class 8; 5 - first and middle reflections (predominantly stands); 6 - points falling within the buildings of the Estonian Topographic Database (ETAK); 7 - noise; 8 - ground depleted points (planned distance >20 or height range +/-0.3); 14 - Points falling into the water bodies of the Estonian Topographic Database (ETAK). The spatial data set is connected with the regulations "Statutes of the Estonian Topographic Database" and "Procedure for acquisition of topographic data and topographic features of general significance".