High Rise buildings penetrating the Annexure 14 surfaces (permitted specifically through Aeronautical studies may affect air safety if not properly controlled. It is also important that they do not form clusters to become large obstacles. (Aeronautical Study for mitigation of new objects is not permitted in the Approach Surface according to GSR 751 (E) issued by MOCA).

Global Coordinates can procure stereo satellite imagery for any area lying within 20km of the ARP to extract the x,y,z of all existing buildings thus capturing the Obstacle scenario as available on the collection date of the satellite image. Following the creation of the building database in real earth coordinates in 2D and 3D, we can run a spatial query to select all buildings with AMSL more than the permissible height i.e all buildings which are penetrating the Obstacle Limitation Surfaces. This gives a birds’ eye view of the current situation. The heights issued in the NOC’s granted by the Airport Authority of India can also be attached as attribute data/ non spatial data to the spatial database created from the stereo satellite imagery in a GIS environment.

Since we can have both the height values attached to Building polygons, namely the permissible as well as the existing AMSL values, it would need a simple query to select the buildings violating the granted height. This will save time, money and effort involved in actually carrying our physical surveys. This methodology will also ensure timely intervention while the building is being constructed compared to moving the huge state machinery for demolition later. Demolition is always a messy affair leading to unnecessary litigation with loss of time and money for the families already living in that part of the building which violates the permissible height norms.

The 3D database thus created will also support in ensuring that the density of buildings penetrating the OLS Surfaces is uniformly distributed and is not concentrated in small pockets. An accurate 2D-3D database of buildings/obstacles around the airport can be very useful to identify and monitor existing and new unauthorized constructions around the Airport.

This ‘Building’ data bank will enable Airport Operators who are responsible for ensuring safety of flights at their respective Airports as also Urban Planners in monitoring of unauthorized buildings by maintaining online surveillance.