Training Course on

‘Marine GIS Applications for Coastal Zone Management’

28 August – September 01, 2017

International Training Centre for operational Oceanography(ITCO),

INCOIS, Hyderabad, India

R S Mahendra

mahendra@incois.gov.in

� Mangroves are a crossroad where oceans, freshwater, and land realms

meet. They are among the most productive and complex ecosystems on

the planet, growing under environmental conditions that would kill

ordinary plants very quickly.

� They are the buffer zone between the land and the sea.

� Mangroves protect the soil from erosion.

Importance of mangrove

� They play an invaluable role as a nature’s shield against cyclones,

ecological disasters and as protector of shorelines.

� They are a breeding and nursery grounds for a variety of marine animals.

Distribution of Mangrove

Mangrove distribution in India

Sources: National Geographic Magazine

Environmental Set up � intertidal zones of estuaries, coastlines, and

islands.

� Form a forest in the tidal zone between land and

sea.

� Found in tropical and subtropical areas

� Thrive in areas of high salinity Mangrove trees

have aerial roots that filter salt out of saltwater

� Rich in biodiversity

� home to countless species of animals, including

fish, shrimp, crabs, mollusc, manatees, sea

turtles, fishing cats, monitor lizards and mud-

skipper fish.

Application of RS in mangrove mapping

• Traditional and historical methods proved to be costly and time

consuming.

• Visual interpretation was the only method used earlier.

• Difficulty to discriminate the different species.

• New emerging data, software and techniques evolved. • New emerging data, software and techniques evolved.

• Satellite imagery up-to-date and available.

• Able to reach remote and inaccessible areas.

• Multispectral and hyper-spectral imagery allows for species

discrimination at different levels and fine detailed mapping.

Mapping Techniques

Field Survey

Random

Transect

Grid

Remote SensingDigital Classification

Supervised Classification: Needs the training sets

Unsupervised Classification: groups pixels into “clusters” based on their properties. Iterative

Random Transect Grid

Unsupervised Classification: groups pixels into “clusters” based on their properties. Iterative

Self-Organizing Data Analysis Technique (ISODATA)

Object based classification: groups pixels into representative shapes and sizes (suitable for high

resolution data)

Visual Interpretation

Manually digitized using the interpretation Keys such as color, tone texture, size, shape,

associated features, etc.

Acc

ura

cy

72 75 98

Advantage and disadvantages of supervised and unsupervised classifications

Image analysis assumptions

• Similar features will have similar spectral responses.

• The spectral response of a feature is unique with respect

to all other features of interest.

• If we quantify the spectral response of a known feature,

we can use this information to find all occurrences of that

feature.

complexityDifferent stage o f mangroves

Different species composition

Leaf types

Association of other vegetation and

water body

Remote Sensing of Mangrove

Plate depicting the ETM spectral window and its

transmission percentage (above). The individual bands

(below).

Table 2 Data set used for the study

Satellite Sensor

Spatial

Resoluti

on

Wavelength

(µm)

Date of

Acquisition

0.52-0.60

0.76-0.90

Identification of hot spots and well managed areas of Pichavaram Mangrove

Landsat TM 30 m

0.76-0.90

1.55-1.75 29/01/1991

Landsat TM 30 m

0.52-0.60

0.76-0.90

1.55-1.75 28/10/2000

Resurcesat-

1

LISS-

IV5.8 m

0.52-0.59

0.62-0.68

0.77-0.86 22/07/2006

Study area

Satellite Data used

Methodology

Radiance conversion: The digital numbers (DN) of each band of all

images are transformed in to real numbers using the spectral

calibration data with the help of graphical programming interface

‘Model Maker’ in ERDAS imagine software. The calibration is given

by the following equation (1) for satellite spectral radiance.

Lrad = {[DN/max grey]*[Lmax - Lmin]} +Lmin ......... (1)

Where

DN = Digital number of a pixel

Max Grey = Maximum DN possible for a given data

Lmax= Minimum radiance value for a given bandLmax= Minimum radiance value for a given band

Lmin=Minimum radiance value for a given band.

Mangrove Mapping– Pichavaram Southeast coast IndiaCase Study: Pichavaram Mangroves

Srinivasa Kumar, T., Mahendra, R. S., Nayak, S., Radhakrishnan, K. R. and Sahu, K. C. (2011) Identification of hot spots and well managed areas of Pichavaram mangrove using Landsat TM and Resourcesat – 1 LISS IV: An example of coastal resource conservation along Tamil Nadu Coast, India. Journal of Costal Conservation, DOI: 10.1007/s11852-011-0162-3, available online.

Mangrove Class

Area in km2

1991 2000 2006

Dense Mangrove 2.76 3.17 5.00

Spatio-temporal variation of Pichavaram Mangroves

Dense Mangrove 2.76 3.17 5.00

Open Mangrove 1.80 3.38 2.06

Total area 4.56 6.55 7.06

Inter Change of Mangrove class

Coral Reef Mapping

Ecological

� The coral reefs are counterpart to the tropical rain forest in terms of speciesrichness and biological productivity in the Ocean. The vast diversity of animaland plant species that contributes to its system and genetic heritage that it

Introduction

What is Coral?

• It’s a living invertebrate organism under class Cnidarians

• 2 different types: Reef Building: Hermatypic and Solitary: Ahermatypic

• Symbiotic relationship with algae Zooxanthella lives in the skin of coral, coral provide

protection to and Zooxanthalle provide food and color.

and plant species that contributes to its system and genetic heritage that itrepresents is increasingly at risk

� Coral reef enables the formation of associated eco-systems which allow theformation of essential habitats, fisheries and livelihoods.

Climatological

� Corals are providing an accurate long-term record of climate change andextending our knowledge of even seasonal climate variability in many remotetropical oceans.habitats, fisheries and livelihoods.

Major threats for the corals

Natural: Environmental-Temperature, Sediment Deposition, Salinity, pH, etc

Anthropogenic: Mining, Bottom Fishing, Tourism, pollution, etc.

Reef Building types

• Corals can build three types of

reefs:

– Fringing: grows close to shore

– Barrier: also grows close to shore – Barrier: also grows close to shore

but has a lagoon separating it

from the shore

– Atoll: a ring of coral that

surrounds a lagoon, often grows

on a submerged mountain or

volcanohttp://www.nos.noaa.gov/education/kits/

corals/media/coral04a_240.jpg

Distribution and Environmental set up

Source: oceanservice.noaa.gov

• Coral is found all over the world:

– Tropical

– Temperate

– Clear water

Coral Reef Remote Sensing

Source: Contreras-Silva et al. 2012

Source: www.seos-project.eu

Eco-morphological Zonation of Coral Reef and Health Modeling

Malvan

Study Areas

Gulf of Kuchchh

Malvan

Gulf of Mannar

A & N Islands

Objectives

�Generation of the eco-morphological maps and Atlas on 1:25000 scales.

Methods

Paper presented at ISRS Symposium, Ahemedabad, India, 2008

Classified maps Changes 2000-2006

The coral reef got exposed

due to 26 December 2004

Sumatra earthquake.

Total area of 7.9 sq. km

area exposed and degraded

Kalubar Island FCC and Classified map

Impacts of 2004 Sumatra earthquake on Andaman Landforms

• The Andaman sea reefs were severely affected and exposed due to December 26, 2004

Sumatra earthquake.

• The Andaman and Nicobar Islands bore the brunt as they were close to the epicenter.

• The Andaman and Nicobar island were uplifted in the northwest and subsided in the

south eastern parts. The present study area Interview island uplifted up to 1 m

Source: NASA, EOS report

Map showing the uplift and subsidence caused by the

2004 and 2005 Sumatra earthquakes with the study area

highlighted(Courtesy: M Tobita, et al, 2005).

Current Sea level

Sea Level before 2004

Current HTL

HTL before 2004

Mangroves

Coral reefs

Sea

Land

Up

lift

Schematic diagram showing the land uplift and subsidence

Mangrove

degradation

Coral Exposure

HTL before 2004

Sea

Land

Su

bsi

de

nce

SpatioSpatio--temporaltemporal changeschanges inin thethe coralcoral environsenvirons duedue toto 20042004 SumatraSumatra EqEq..

Tectonic disturbances Total Coral Area Exposed Reefs

AndamanAlgae and Seagrass

Algal Ridge

Beach/ Sand Pat ch

Channel

Coral Heads

Coralline Shelf

Deeper Inner Reef Flat

Deeper Reef Flat

Exposed Reef Flat

Exposed Reef Flat (Algae)

Exposed Reef Flat (Sand)

Inner Reef Flat

Live Corals

Mud Flat

Muddy Reef Flat

Out er Reef Flat

Reef Crest

Reef Flat

Reef Slope

Rock

Sand Cay s

Sanded Reef Flat

Sandy Muddy Reef Flat

Shallow Pools

Sparse Algae

Sparse Algae on Boulder Zone

Sparse Algae on Muddy Reef Flat

Sparse Algae on Reef Flat

Submerged Reef

Submerged Rock s

Windward Reef Front

Sparse Algae on Sandy Muddy Reef Flat

Total area of exposed category recorded ~113 km2 from Andaman Islands

Field Photos

Sea

Debris of coral

Corals thrown out and overturnedPools

Pools

Mangroves

Exposed corals

Exposure 0.9 m observed above water level

Exposed coralsAndaman and Nicobar

Remotely Operated Vehicle (ROVe) for coral samplingApril 2016 North bay Andaman

SpatioSpatio--temporaltemporal changeschanges inin thethe MangroveMangrove environsenvirons duedue toto 20042004 SumatraSumatra EqEq..

Total ~49.24 km2 areas of mangroves were degraded during 2000-2006 in the Andaman coast.

Spatio temporal changes in the mangroves cover in the northern parts of interview island

Accuracy Assessment Sampling

• Random sampling

• Systematic sampling

• Stratified random sampling

• Stratified systematic unaligned sampling

• Cluster sampling

Agreement/accuracy: the probability (%) that the classifier has labelled an image pixel into

the ground truth Class. It is the probability of a reference pixel being correctly classified.

Overall accuracy: the total classification accuracy

Commission error: represent pixels that belong to another class but are labelled as belonging

to the class.

Omission error: represent pixels that belong to the truth class but fail to be classified into the

proper class.

Kappa coefficient(Khat): a discrete multivariate technique of use in accuracy assessment.

Khat>0.80 represent strong agreement and good accuracy. 0.40-0.80 is middle,

Types of Classification accuracy with example

Cntd.......

The Remote Sensing and GIS techniques used in

concurrence with the satellite data gives fairly better results

in understanding the spatio-temporal changes in mangroves

Remarks

and coral reefs along the coastal zones. In light of all these

facts and analyses, it can be concluded that there is a

strong need to make necessary coastal management

programs and implement them in potential risk zones.

Thank YouThank You