Aerial Mapping of Areas Affected by “Seroja” Tropical Cyclone in East Sumba Using Site Scan for ArcGIS
On April 5, 2021, the TCWC (Tropical Cyclone Warning Center) Jakarta gave a statement regarding to the first warning about Tropical Cyclone 26S from JTWC (Joint Typhoon Warning Center). The Tropical Cyclone 26S transformed into Tropical Cyclone Category 1 and had been named “Seroja” by that day, at 04.00 AM Central Indonesian Time [1].
This disastrous cyclone resulted in damage to around 15,500 hectares of agricultural land spread accross 18 of 23 cities/regencies in East Nusa Tenggara region, and more than 27,000 residents had to evacuate as update per April 10, 2021. Timor Leste had affected by this disaster as well. As of 8 April, the death toll in Timor Leste was recorded at 42 people [2][3].
Esri Indonesia’s ESSC (Emergency Spatial Support Center) Team took part in humanitarian operations with any volunteer organizations, such as U-Inspire Indonesia, Sky Volunteer, etc. which were supervised by Indonesia’s National Board for Disaster Management or Badan Nasional Penanggulangan Bencana (abbv.: BNPB). From Esri Indonesia, Daniel Maynard Samosir and I were delegated to go to the affected area.
Esri Indonesia and Sky Volunteer (represented by Septian Firmansyah & Luqman Aditya) were deployed to East Sumba regency to map the areas which affected the most. On the first day, we’re headed to Bendung Kambaniru, which is located in Kambera sub-district. The biggest water dam in East Sumba regency was severely damaged due to flash floods on April 4, 2021. The damage to Kambaniru dam caused 1,440 hectares of rice fields in Kambera sub-district to be unable to plant rice in the second plant season in 2021 [4].
Data Acquisition & Processing Using Site Scan for ArcGIS
Our main activity in East Sumba was conducting drone mapping, started from collecting imagery data to analyze the data and generate outputs such as orthophoto, DEM (Digital Elevation Model) file, DTM (Digital Terrain Model) file, and 3D models. By using Site Scan for ArcGIS, we could create flight plan and execute it automatically, until processing the data in a scalable cloud environment to create high-quality 2D & 3D imagery products that can be quickly shared [5].
After the mission has been completed, we could upload the images from our drone to Site Scan Manager’s cloud storage by selecting recent flight and upload the images directly. Or, you also could upload the images from your organizations page by signing in to Site Scan (arcgis.com).
For the data analysis, it could be done by simply clicking the “Process” button, do a few set-ups for the outputs, and…. Voila! Grab your black coffee and gluten-free cookies, just wait, and let these “Map Fairies” (re: some magical things that happened on this “cloud”) do their duties!
Here are some outputs from our aerial surveys in East Sumba:
- Orthophoto of Bendung Kambaniru (Kambaniru water dam), ground res. 120 m.
2. Comparison of pre & post-disaster at Bendung Kambaniru.
3. 3D model of Bendung Kambaniru (post-disaster).
This disaster was a serious “blow” to Indonesia and the people of East Nusa Tenggara in particular. We hope that the recovery runs well, so that all can return to normal. God Bless Indonesia!
References:
1. https://id.wikipedia.org/wiki/Siklon_Seroja
2. “Ribuan Hektar Sawah di NTT Terancam Puso”. Kompas. April 14, 2021. Page 11.
3. “Indonesia president visits cyclone-hit islands”. France 24. April 9, 2021
4. “Kambaniru, Bendungan Terbesar di Sumba Jebol Akibat Banjir!”. detik.com. April 6, 2021.
5. Cloud-Based Drone Mapping Software | Site Scan for ArcGIS (esri.com)
