Prof Muh Aris Marfai

Potential Use of Airborne SAR Interferometry for the Acceleration of Nationwide Large-scale Topographic Base Mapping in Indonesia

Indonesia as one of the largest tropical archipelagic countries in the world, includes more than 17,000 islands, characterized by very diverse and complex land cover, topographically varies from flat to mountainous with very extensive cloud cover, even almost permanent in some areas. This makes Indonesia a very challenging region in the field of topographic survey and mapping. Topographic survey and mapping activities often encounter obstacles due to cloud cover, especially in the application of remote sensing technology using optical sensors on various platforms such as drone (UAV), airborne and spaceborne systems.

Unlike optical sensors, radar sensors or currently known as Synthetic Aperture Radar (SAR), which is an active remote sensing system, has the ability to penetrate clouds, fly higher with wider coverage so that acceleration can be carried out and overcome the main obstacles of topographic survey and mapping. SAR technology uses the so called interferometry technique / Interferometric SAR (InSAR or IFSAR)  in the field of topographic mapping, particularly in creating DEM (Digital Elevation Model) showing a very promising trend and reach up to sub-meter level of vertical accuracy.

The Philippines and Malaysia, which have characteristics and geographical conditions similar to Indonesia as tropical countries with extensive cloud coverage, have used airborne InSAR technology for their nationwide large-scale topographic mapping in 2013 and 2017, respectively. Indonesia will carry out nationwide large-scale topographic base mapping at 1:5.000 scale using hybrid technology for the next 5 years. Photogrammetry and LiDAR technology will be used for topographic base mapping of urban areas whilst Airborne InSAR will be used for rural and forest areas, respectively. The provision of medium- and small-scale base maps will be produced by an automatic generalization method from larger-scale base maps. The Availability of multi-scale base maps are mainly aimed to support national spatial planning programs.