monitoring outermost island with airborne lidar bathymetry

The Study of Monitoring the Outermost Islands of Indonesia Using Airborne Lidar Bathymetry

European Lidar Mapping Forum, November 2011


A. Rimayanti1, T. Patmasari1, T. Fayakun Alif2 1Center for Boundary Mapping, BAKOSURTANAL, [email protected]

1Center for Boundary Mapping, BAKOSURTANAL, [email protected] 2Center for Basemap Marine and Aeronautical Chart, [email protected]

Abstract

Indonesia as an archipelagic state has approximately 13.487 islands with 92 small outermost islands that spread over in all provinces in Indonesia. These small outermost islands have an important value because of its strategic position where the basepoints which form the Indonesian Archipelagic baselines were placed. The baselines are used to define various maritime jurisdictions, including territorial seas, contiguous zones, exclusive economic zones and continental shelves. The issues of global warming which arise nowadays give many impacts such as sea level rise. The sea level rise may cause the submergence of the small islands. Thus the small islands especially the small outermost islands which have strategic value need to be maintained. One alternative that can be used to solve the problem is to apply a technology which is cost effective, fast and accurate such as Airborne Lidar Bathymetry. This paper will examine monitoring of the small outermost islands of Indonesia using Airborne Lidar Bathymetry.

Key words: outermost island, Lidar bathymetry, Indonesia

The Study of Monitoring the Outermost Islands of Indonesia Using Airborne

European

I. Introduction

Figure 1. Map of Indonesia (Bakosurtanal, 2011)

Indonesia as archipelagic state in addition to having a vast ocean and a long coastline which is one of the longestincluding the small outenvironmental services with small outermost islands have more strategic values basepoints which form the Indonesian Archipelagic baselines. The are used to define various maritime jurisdictions, including territorial seas, contiguous zones, exclusive economic zones and continental shelves.which connect the Indian Oceans and the Continent and Australia Continent makes Indonesia’s small outermost islands in dangerous position in the enforcement of sovereignty.

The strategic position ofimmediately clarify the boundariesbecause most of the bordering areathat it needs a good management

The issues of global warming which arise nowadays give many impacts such as sea level rise. Among the many impacts of global warming, only seadisplaces people and their communities. Uespecially important since islands. Thus the small islands especially the small outermost islands which have strategic values need to be maintained. Onelevel rise onto the small outermost island is to apply the technology such as Bathymetry. This paper will examine the monitoring of the smallIndonesia using Airborne Lidar

Monitoring the Outermost Islands of Indonesia Using Airborne Lidar



Indonesia as archipelagic state in addition to having a vast ocean and a long coastline which is one of the longest coastlines in the world, Indonesia also has many islands

outermost islands that have assets of natural resources and environmental services with an enormous potential for development economy.small outermost islands have more strategic values because of its strategic position

ch form the Indonesian Archipelagic baselines. The archipelagic are used to define various maritime jurisdictions, including territorial seas, contiguous zones, exclusive economic zones and continental shelves. The strategic position of the Indonwhich connect the Indian Oceans and the Pacific Oceans and in the middle of Asia Continent and Australia Continent makes Indonesia’s small outermost islands in dangerous position in the enforcement of sovereignty.

The strategic position of the small outermost islands enforcesboundaries with the neighboring countries. This is very important

because most of the bordering areas are in the sea and in the small outermost islands.management of all stakeholders including the policy makers.

The issues of global warming which arise nowadays give many impacts such as sea Among the many impacts of global warming, only sea

displaces people and their communities. Understanding the impacts of especially important since the sea level rise may cause the submergence of the small islands. Thus the small islands especially the small outermost islands which have strategic

need to be maintained. One alternative that can be used to monitor the impact of sea level rise onto the small outermost island is to apply the technology such as Bathymetry. This paper will examine the monitoring of the small

Lidar Bathymetry.

Lidar Bathymetry


Indonesia as archipelagic state in addition to having a vast ocean and a long coastline in the world, Indonesia also has many islands

of natural resources and potential for development economy. In fact, these

because of its strategic position as the archipelagic baselines

are used to define various maritime jurisdictions, including territorial seas, contiguous zones, The strategic position of the Indonesia

Oceans and in the middle of Asia Continent and Australia Continent makes Indonesia’s small outermost islands in dangerous

enforces the government to . This is very important

in the sea and in the small outermost islands. So of all stakeholders including the policy makers.

The issues of global warming which arise nowadays give many impacts such as sea Among the many impacts of global warming, only sea-level rise physically

nderstanding the impacts of global warming is he sea level rise may cause the submergence of the small

islands. Thus the small islands especially the small outermost islands which have strategic monitor the impact of sea

level rise onto the small outermost island is to apply the technology such as Airborne Lidar outermost islands of



II. Outermost Islands in Indonesia

Indonesia’s sovereignty over the islands, by law, doesn’t depend on location or small/large islands, or whether populated islands or not. Indonesia’s sovereignty over all its territory and sovereign right and jurisdiction over all matters which entitled to Indonesia, or its interest in the high seas and international seabed, is essentially the same for the entire region, nation and state. (Djalal., Hasjim, 2011). As mentioned above Indonesia is an archipelagic state which has so many islands, there are almost 14.000 islands. The government of Indonesia will register 13.487 islands including small outermost islands to the United Nation next year. This is to confirm the existence of these islands as part of Indonesia. According to the Presidential Regulation Number 78 Year 2005 of the management of the small outermost islands, there are 92 outermost islands in Indonesia. These outermost islands as mentioned above adjacent to neighboring countries.

According to the Presidential Regulation Number 78 Year 2005, small outermost island is the island with an area less than or equal to 2000 km2, which has basepoint that connect archipelagic baselines in accordance with national and international law. Outermost islands as mentioned above serve as the front line of sovereignty and jurisdiction of Indonesia.

The management of the outermost islands has the objectives: a. Maintain the territorial integrity of Indonesia, the national security and defense and

create the stability in the region.

b. Utilize natural resource in the framework of sustainable development

c. Empower the community to increase the welfare.

During this time, there are some problems relating to the management of outermost

islands including the existence and the continuity of the existence of the islands itself, the

welfare of the community in the islands and the isolated island location.

Due to the global warming which engulf the world including Indonesia and gives impact

such as sea level rise which could sinking the small islands, the government of Indonesia

must take some real management actions so that the existence of the outermost islands as

the front line of the Indonesian boundary line with neighboring countries can still well

preserved. The geospatial data and information are needed as one of tools in the

management of outermost islands. The geospatial data and information can be obtained

from technology such as Airborne Lidar Bathymetry.

The Study of Monitoring the Outermost Islands of Indonesia Using Airborne

European

Figure2. The Outermost Islands

III. Airborne Lidar Bathymetry

3.1 What is Lidar? Lidar which is known as Light detection and ranging is a

can be used to obtainLidar is an active remote sensing which Lidar is collected from planes and produces a rapid collection ofsecond) over a large collection area

There are three technologies which are integrated in

(i) Laser ranging for accurate distance measurement,

(ii) Satellite positioning using the Global Positioning System (GPS)

(iii) Aircraft attitude measurement using an inertial measurement unit (IMU) to

record the precise orientation of the sensor.

These three technologies are working together and collected data with the same

time. As mentioned above, Lidar is an active sensor so it allows

at night when the air is clearer

types of Airborne

topographic surface mapping

Airborne Lidar Bathymetry

Monitoring the Outermost Islands of Indonesia Using Airborne Lidar


2. The Outermost Islands in Sumatera, Indonesia (Bakosurtanal, 2011)

Bathymetry

which is known as Light detection and ranging is a mapping can be used to obtain height and depth information of features.Lidar is an active remote sensing which employs light pulses instead of radio waves. Lidar is collected from planes and produces a rapid collection ofsecond) over a large collection area.

There are three technologies which are integrated in Airborne

Laser ranging for accurate distance measurement,

Satellite positioning using the Global Positioning System (GPS)

attitude measurement using an inertial measurement unit (IMU) to

record the precise orientation of the sensor.


As mentioned above, Lidar is an active sensor so it allows

at night when the air is clearer and also in the fair weather.

types of Airborne Lidar System, Airborne Lidar Topography which is used for

topographic surface mapping, collect elevation data through elevation model and

Airborne Lidar Bathymetry which is used for water depths mapping. Both system in

Lidar Bathymetry

(Bakosurtanal, 2011)

mapping technology that height and depth information of features. According to NASA

light pulses instead of radio waves. Lidar is collected from planes and produces a rapid collection of point (± 7000 per

Airborne Lidar such as:

Satellite positioning using the Global Positioning System (GPS)

attitude measurement using an inertial measurement unit (IMU) to


As mentioned above, Lidar is an active sensor so it allows Lidar to be collected

Mainly there are two

Airborne Lidar Topography which is used for

collect elevation data through elevation model and

mapping. Both system in



the measurement using aircraft or helicopter as vehicle to put the Lidar tools which

emit the laser beam and uses light waves.

Figure 3. Lidar Technology (Fayakun, 2010)

Lidar is similar to radar (radio detection and ranging) except that is Lidar based on discrete light pulses and measured travel times. The location and elevation of the reflecting surface are derived from 1) the time difference between the laser pulse which is being emitted and returned, 2) the angle and 3) the location and height of the aircraft (Guenther, 2000). While the time delay between the transmitted pulses and the detection of the reflected signal are taken as a distance of an object.

3.2 The Principle of Airborne Lidar Bathymetry

Airborne lidar bathymetry is also known as Airborne Lidar hydrography in term of

nautical charting. Airborne Lidar bathymetry involves the use of a pulsed laser

transmitter with both green and infrared (IR) output beams.



Figure 4. The Characteristic of the Green and IR Pulse (Guenther, 2000) Green is selected because of the wavelength which can penetrate the coastal

water and for sea bottom detection while the IR can be used for detection of the sea surface location. The transmitter laser pulses partially travel to the water surface, some of the energy reflects back to the receiver. The remaining energy which propagates through the water column reflects off the sea bottom back to the airborne receiver. The water depths are determined from the time differences between the surface return and the bottom return while the distances to the sea surface and bottom can be calculated by measuring the times of flight of the pulses to those locations by knowing the speed of light in air and water.

Figure 5. The Principle of ALB (Irish, J. L., 2000)



3.3 Factors Affecting ALB

Many factors contribute to the ability of ALB in penetrating the area in its path, this ability depends on the medium in which the pulses are emitted. Several factors which affect the strength of Lidar pulse in water are:

a. Environmental factor: water clarity The most significant limitation for ALB system is water clarity, which limits the maximum surveyable depths. The maximum surveyable depth is the greatest depth, at a given time and location for which depth measurement can be obtained. This requires that the bottom-return signal be reasonably strong and free from excessive noise (Guenther, 2000). In many areas, if the water is too dirty for a survey to be successfully performed on a given day, it may only be necessary to return to the site at several days later to find the acceptably clear water.

b. Turbidity The energy of light through water medium, its intensity will be influenced by: - Absorption and or conversion into other energy - The scattering energy into all direction

Both components will reduce the energy and directly proportional to the depth. The reduction of the energy caused by absorption and scattering is known as turbidity. In optically clear water, ALB sensors have successfully measured to depths to 70 m (Sinclair, 1999).

c. The composition of sea bottom

Vegetation in the sea bottom influences the reflectivity of sea bottom and reduction of depths penetration. The penetration ability of Lidar pulse depends on the composition of sea bottom (sand, phytoplankton, mud, etc). Phytoplankton and other particle matter have an effect on how light is absorbed and scattered in the water. Phytoplankton contains chlorophyll which absorbs light at the violet and red side of the spectral range, at the same time as allowing green light to experiences the deepest water penetration (Mcnair., Gordon, 2010).

d. Weather The weather condition such as the rainfall, strong wind and the high tide influence the ability of laser light penetration and the ability of depth penetration.



Figure 6. Light Penetration in Coastal Water (Mcnair., Gordon, 2010)

IV. Monitoring the Existence of the Outermost Islands of Indonesia using ALB

As mentioned above the outermost islands of Indonesia need to be well managed because of its strategic roles and position in the Indonesian archipelago. To be well managed needs a tool which is effective, efficient, faster, accurate and off course low cost. The management of the outermost islands of Indonesia will covers the collection of hydrographic depths to determine the position and condition of the islands and also shoreline. One tool that can be used to manage it is by using Airborne Lidar Bathymetry.

Currently the mapping system using laser beam which is carried out by aircraft is still the most efficient mapping system compared with conventional mapping, photogrammetry and remote sensing. The ALB can collect ± 7000 per second over a large area. This condition makes lidar faster and accurate. Although the ALB is efficient, the use of ALB in Indonesia is still minimal because in any ways recording requires a significant financial cost to lease the aircraft and most of the uses done by mining company. But to obtain the efficient and accurate of ALB, the paper try to study the performance and the ability of ALB to monitor the outermost islands of Indonesia.

As mentioned above one of the limitations if using the ALB is weather condition and water clarity. Indonesia which is in the tropical climate having temperature varies from season to season and the main variable in Indonesia’s climate is not temperature or air pressure, but rainfall. The significant rainfall throughout Indonesia is produced by the prevailing wind patterns which interact with local topographic condition. The rainfall in some areas will affect in the water clarity and the turbidity. Beside these two things, the rainfall will also affect the movement of the aircraft to retrieve the data from one point to another point so it impedes the schedule time. To be able to perform the measurement using the ALB based on the water clarity and turbidity, one step which can be done is to identify mentioned factors for the small outermost islands of Indonesia. Here are examples of water quality from three outermost islands of Indonesia, Makalehi and Mantehage and Bangkep. These islands are located in the Sulawesi Island as Main Island.



Water Quality of Makalehi FID Shape * Latitude Longitude Temperature Salinity Ph Turbidity Clarity

0 Point 2.7455 125.1663 28.9 3.66 8.13 1 4.2

1 Point 2.7385 125.1779 28.9 3.67 8.15 1 9.1

2 Point 2.7297 125.1646 29.4 3.67 8.19 1 8.7

Water Quality of Mantehage FID Shape

*

Administration Temperature Conductivity Turbidity Clarity X Y Salinity Ph

0 Point P. Kepar 29.5 52.1 2 2,8 108.241306 -3.14975 3.44 8.2

1 Point P.Tapok 29.2 50.8 7 2 108.209861 -3.145333 3.34 8.2

2 Point P.Tepi 29.7 52.2 1 3,5 108.199389 -3.21775 3.44 8.22

3 Point P. Rotan 29.2 52.2 1 5 108.272194 -3.223056 3.47 8.2

4 Point P. Mariam 29.6 52.6 1 6,8 108.28825 -3.229389 3.47 8.22

5 Point Buku Limau 29.3 52.3 1 11 108.399194 -2.807694 3.45 8.22

6 Point P. Siadong 29.8 52.7 2 7 108.419778 -2.790417 3 8.21

7 Point P. Bakau 29.5 52.4 1 11 108.419583 -2.673306 3.49 8.22

8 Point Gosong Bakau 23.6 52.9 2 11 108.419583 -2.673306 3.49 8.24

9 Point P. Mulut 29.5 52.6 0 4,3 107.051417 -2.536611 3.47 8.18

10 Point P. Mulut 29.4 51.6 1 5 107.085222 -2.546889 3.4 8.17

11 Point Gosong Kupit 30.4 50.3 1 4 108.035722 -2.574972 4.45 8.3

12 Point P. Lima 29.1 52.8 1 9,3 107.356556 -3.080722 3.49 8.19

13 Point P. Seliu 29.3 52.2 1 3,2 107.51375 -3.231722 3.44 8.31

14 Point Tg. Lancur 29.4 52.6 0 3,1 107.342528 -2.878139 3.47 8.23

15 Point P. Goal 29.3 52.3 1 1,5 107.372556 -2.919722 3.45 8.27

16 Point Tg. Mentigi 29.2 51 2 3 107.672389 -3.239528 3.36 8.32

17 Point P. Batumana 29 50.7 0 2,2 107.543278 -3.755806 3.33 8.29

18 Point Busung Arah 29.1 51.7 1 5,3 107.538944 -2.8545 3.41 8.31

19 Point Tg. Tikar 29 50.9 1 2,5 107.5725 -2.794833 3.37 8.27

20 Point Karang Kijang 29.7 50.2 2 3,5 107.582389 -2.739056 3.35 8.31

21 Point Tg.Binga 29.9 51.9 1 5,3 107.620333 -2.601694 3.42 8.35

22 Point Tg. Tinggi 29.5 52.5 1 3,6 107.711056 -2.548194 3.47 8.32

23 Point P. Lengkuas 29.3 52.1 2 4,5 107.617972 -2.538139 3.44 8.34

24 Point P. Burung 29.3 52.4 2 2 107.626667 -2.564306 3.45 8.34



Water Quality of Bangkep NO Station X Y Administratio

n

Temp SAL TURB CL PH DO DEPTH

1 RRA 23 123,0665 -1,9260 Taduno 28,80 3,51 0,00 2,10 7,80 4,90 2,10

2 RRA 24 123,0597 -1,8286 Tabulang 28,50 3,23 80,00 3,00 7,91 4,94 3,00

3 RRA 22 123,1386 -1,7964 bone-bone 29,00 3,53 0,00 4,50 7,90 5,16 4,50

4 RRA 26 123,1841 -1,8006 P. Bangku 28,90 3,56 0,00 1,80 7,95 4,79 1,80

5 RRA 18 123,1490 -1,9248 Pulau 28,90 3,57 0,00 1,60 7,90 4,57 1,60

6 RRA 17 123,2813 -2,0676 P.ganemu 29,30 3,58 0,00 1,50 8,03 4,84 1,50

7 RRA 57 123,3257 -2,0949 P.silumba 29,20 3,58 0,00 2,00 7,95 4,94 2,00

8 RRA 15/KA 1 123,2647 -1,9834 P. saluka 28,70 3,59 0,00 14,00 7,88 4,91 17,00

9 RRA 15 123,3407 -2,0110 mandibelu 29,30 3,55 119,00 2,00 7,94 5,05 2,00

10 RRA 14 123,4772 -1,9881 P.bulutan 2,00 3,56 0,00 2,10 7,95 7,76 2,10

11 RRA 5 123,6298 -1,9421 teropot kec 28,70 3,58 0,00 2,60 7,92 6,47 2,60

12 RRA 1 123,7484 -2,0265 Gasueng 28,40 3,59 0,00 1,70 7,84 5,53 1,70

13 RRA 11 123,7625 -2,1007 P.Tanalan 29,20 3,45 0,00 2,60 7,84 5,19 2,60

14 RRA 8 123,8663 -2,0040 P.dekendek 29,00 3,60 1,00 3,50 7,92 5,10 3,50

15 RRA 10 123,5938 -2,0564 P. jodoh 28,60 3,59 0,00 3,00 7,93 5,33 3,00

16 RRA 16 123,4537 -2,1192 P. burung 29,80 3,58 0,00 2,90 7,97 5,14 2,90

17 RRA 32 123,4519 -1,6849 P. bandang 30,10 3,54 0,00 2,00 8,05 5,35 2,00

18 RRA 30 123,6021 -1,7105 Matanga 27,90 3,53 0,00 2,80 7,85 5,32 2,80

19 RRA 29 123,6185 -1,6393 Umbuli 28,00 3,55 1,00 4,50 7,88 5,81 4,50

20 RRA 28 123,5604 -1,5533 Kendek 28,30 3,56 0,00 2,50 7,88 5,51 2,50

21 RRA 33 123,5172 -1,4809 P. Popisi 28,60 3,60 0,00 3,70 8,05 6,34 3,70

22 RRA 42 123,4177 -1,5160 Tg. Curahtu 28,90 3,54 111,00 1,80 7,95 5,39 1,80

23 KA 2 123,4809 -1,5856 Bato-bato 28,70 2,25 3,00 2,50 7,95 6,01 3,90

24 RRA 40 123,3606 -1,5184 Bobu 29,00 3,53 2,00 6,80 7,95 5,81 6,80

25 KA 3 123,3298 -1,5491 Tl. Tinakun 28,60 3,50 6,00 16,00 7,98 7,73 95,00

26 RRA 37 123,2422 -1,6490 Tg. Pinalun 29,10 3,48 0,00 2,80 7,94 8,10 2,80

27 RRA 27 123,0064 -1,7403 Rip. Melati 29,30 3,52 0,00 1,50 8,02 8,32 1,50

28 KA 4 123,0699 -1,5100 Tl. Peling 29,70 3,46 0,00 13,00 7,90 8,08 80,00

29 RRA 55 123,0478 -1,4084 Unu 28,80 3,43 0,00 4,60 7,80 6,38 4,60

30 RRA 54 122,8464 -1,5913 Tg. Kambani 29,30 3,53 34,00 4,50 8,01 5,77 4,50

31 RRA 51 122,7819 -1,4812 P. Sabalade 29,60 3,45 0,00 6,20 7,95 6,27 6,20

32 RRA 49 122,7508 -1,3338 P.tikus 31,10 3,44 2,00 2,00 8,99 9,00 2,00

33 RRA 47 122,9564 -1,1964 Lukpanenete 28,60 3,57 0,00 2,60 7,77 9,73 2,60

34 RRA 46 123,0772 -1,1697 Sabang 29,40 3,66 1,00 2,40 8,07 7,73 2,40

35 KA 5 123,1408 -1,1971 Sambolangan 29,10 3,58 0,00 1,60 8,06 7,81 1,60

36 RRA 48 123,2484 -1,2307 Montok 28,70 3,35 1,00 2,80 7,92 8,32 2,80

37 RRA 45 123,2783 -1,1763 P. Bakalan 28,70 3,54 0,00 2,00 8,02 8,39 2,00

38 RRA 44 123,3255 -1,2121 P. Bakalan 29,10 3,53 0,00 4,80 7,95 8,34 4,80



From the data above, it can be concluded that the water quality of Makalehi Island,

Mantehage Island, and Bangkep Island are in stable condition, where the lidar pulse can

penetrate the water. Therefore, the ALB can be applied in Indonesia, especially in these

outermost islands and its surrounding.

V. Conclusion

To be able to know whether the ALB is capable to be applied in Indonesia especially

to monitor the existence of the outermost islands of Indonesia, the water quality data and

the weather factors should be included as the affecting factors. From the samples of the

water quality data of the three outermost islands of Indonesia, Makalehi Island, Mantehage

Island, and Bangkep Island it can be concluded that the ALB can be used as one of the

alternative mapping system for monitoring outermost islands which can be applied in

Indonesia. By some notes that for the measurement can be best done in the dry season

which extends from June to October. As mentioned above, the ALB depends on the weather

factor, as it will relate to the quality of generated data.

VI. References 1. Djalal., Hasjim, Menjadikan Pulau-Pulau Kecil Terluar sebagai Pusat

Pertumbuhan, Jakarta, 2011. 2. Fayakun., Teguh, Survei Airborne Lidar Batimetri, Pusat Pemetaan Dasar

Kelautan dan Kedirgantaraan, Cibinong, 2010. 3. Guenther, G. C., Cunningham, A. G., LaRocque, P. E., and D. J. Reid,

Meeting the accuracy challenge in airborne lidar bathymetry. Proceedings, EARSeL Symposium 2000. Dresden,Germany, 2000.

4. Irish, J. L., An Introduction To Coastal Zone Mapping with Airborne LIDAR : The Shoals system, US Army Engineer Research and Development Center Coastal and Hydraulics Laboratory,USA, 2000.

5. McNair., Gordon, Coastal Zone Mapping using Airborne Laser Bathymetry, Norwegian University of Life Sciences, 2010.

6. Presidential Regulation Number 78 Year 2005 of the Management of The Small Outermost Islands.

7. Schmid, Keil, “Lidar 101: An Introduction Lidar Technology, Data, and Applications.” Charleston, SC: NOAA Coastal Services Center, National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center, 2008.

8. Sinclair, M., Laser hydrography – commercial survey operations, Proceedings, US Hydrographic Conference ’99. Mobile, Alabama, USA, 1999

9. http://coastal.er.usgs.gov/capabilities/airborne/index.html by November 2, 2011.

monitoring outermost island with airborne lidar bathymetry

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