CoastWatch UNESCO Bilko Project Module 7
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Module7.pdf Module 7: Applications of Satellite and Airborne Image Data to Coastal Management

 

Lessons by: A.J. Edwards1and P.J. Mumby2

with assistance from E.P. Green1,3 and C.D. Clark2

Bilko for Windows Software by: M. Dobson4 and R. Callison4

Introduction to Bilko for Windows software by: A.J. Edwards1

Introductory Tutorials by: I.S. Robinson5

 

 

A CONTRIBUTION TO "AGENDA 21" IMPLEMENTATION

 

 

1. Centre for Tropical Coastal Management Studies, University of Newcastle upon Tyne, U.K.
2. Sheffield Centre for Earth Observation Science, University of Sheffield, U.K.
3. Present address: World Conservation Monitoring Centre, Cambridge, U.K.
4. Pharos Scientific Ltd., Dundee, U.K.
5. School of Ocean and Earth Sciences, University of Southampton, U.K.

PREFACE

 The majority of the world's population live in coastal regions. Increasing competition for the diminishing resources in coastal areas and the growing disparity between those who have and those who have not, make coastal belts potential flash points for resource conflict. Often these conflicts may be between, on the one hand the pressures of global tourism, poorly implemented industrialisation, or inappropriate aquaculture developments, and on the other, local communities dependent on coastal resources who find these threatened by such external forces. To manage such coastal areas is a unique and complex challenge. Integrated coastal management (ICM) seeks to rise to this challenge by co-ordinated planning and action involving communities, stakeholder groups and managers at local, regional and national level as well as both natural and social scientists.

As a first step to coastal management and planning, managers need to map existing coastal habitats and resources and determine how these relate spatially to areas of urban, industrial, aquaculture, tourism and other developments. This allows sites of potential conflict, high biodiversity, inappropriate development, high sensitivity to environmental impacts, etc. to be identified and for management initiatives and scarce resources to be targeted accordingly.

The primary tool for mapping coastal habitats and resources is remote sensing using satellite sensors and, increasingly, airborne digital scanners. This remote sensing distance-learning module, the seventh in the Bilko series, focuses on these coastal management applications. In eight practical lessons it gives users a thorough grounding in a suite of coastal management related remote sensing tasks, ranging from acquisition of appropriate imagery and interpretation of coastal images, through radiometric and water column correction, to mapping of coastal marine habitats and quantitative assessment of seagrasses and mangroves. The module seeks through its training to improve the quality of spatial data available to coastal managers and planners and thus ultimately to improve the management of the coastal resources on which local communities depend.

 

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INTRODUCTION

 This is the seventh computer-based learning module prepared in UNESCO's Bilko project and the first developed to address the objectives of the Environment and Development in Coastal Regions and in Small Islands programme (CSI: http://www.unesco.org/csi). It is the second to use a Windows based version of the BILKO software (Bilko for Windows). Like its predecessors which used versions of the original MS-DOS based BILKO software (Modules 1-5: obtainable from http://www.unesco.bilko.org/) and an earlier version of Bilko for Windows (Module 6), it contains a series of lessons based on the display of data in image form and it demonstrates the processing and interpretation of these images using Bilko for Windows. Unlike earlier modules, Module 7 requires that Excel (or a spreadsheet package which can read Excel files) also be installed.

Coastal management

Unlike previous modules, which had a more broadly based focus, Module 7 is strongly orientated towards coastal management applications in tropical countries.

Habitat maps derived using remote sensing technologies are widely and increasingly being used to assess the status of coastal natural resources and as a basis for coastal planning and for the conservation, management, monitoring and valuation of these resources. Digital sensors commonly used for coastal management applications have spatial resolutions ranging from about 1-80 m and spectral resolutions ranging from a single panchromatic band to around 16 precisely defined wavebands which can be programmed for specific applications. Costs of imagery range from about £0.25k for a low-resolution (80 m pixel) satellite image covering 35,000 km² to perhaps £80k for a high-resolution (3 m pixel) airborne multispectral image covering less than half this area. In addition, high-resolution analogue technologies such as colour aerial photography are still in routine use. Coastal managers and other end-users charged with coastal planning and management and the conservation and monitoring of coastal resources require guidance as to which among this plethora of remote sensing technologies are appropriate for achieving particular objectives. To this end the UK Department for International Development (DfID) have funded production of a Remote Sensing Handbook for Tropical Coastal Management. Module 7 complements this Handbook by providing training for practitioners on how to carry out key image processing steps that are particularly important for coastal management applications. It also guides practitioners in the mapping of coral reef, seagrass and mangrove ecosystems and the quantitative assessment of the status of the latter two resources using airborne and satellite imagery.

The satellite and airborne images used in this module are all of the Caicos Bank area of the Turks and Caicos Islands which lie to the south-east of the Bahamas. This area was chosen as a test site to discover what coastal management objectives are realistically achievable using remote sensing technologies and at what cost. This site offered good clear-water conditions, a broad mix of coastal habitat types, a very large area (>10,000 km²) of shallow (<20 m deep) coastal waters which would be amenable to the technologies. Module 7 builds on the experience gained in our investigation for DfID of the capabilities of the range of sensors in wide current use. The objectives of using remote sensing should always be clearly defined so that appropriate imagery is obtained and adequate processing is carried out. The objectives of coastal managers in using remote sensing are listed below.

Uses of remote sensing in the coastal zone

Worldwide, sixty coastal managers and scientists (out of 140 contacted) responded to a questionnaire in which they were asked a) to identify what they saw as the primary applications of remote sensing and b) to prioritise the usefulness to them of various levels of information on coastal systems.

The most in-demand applications of remotely-sensed data were to provide background information for management planning and to detect coastal habitat change over time (Figure 1). The term "background information" reflects the vagueness with which habitat maps are often commissioned and indicates a need for objectives of remote sensing surveys to be defined more rigorously. 70% of respondents who were using remote sensing for change detection were concerned with mangrove assessment and/or shrimp farming. The primary uses made of the habitat/resource maps are shown in Figure 1.

Use of habitat/resource maps

Figure 1. Responses of 60 coastal managers and scientists to a questionnaire asking them to identify what they considered the primary applications of remote sensing for tropical coastal management.

The minimum recommended level of computing hardware is a Personal Computer with a reasonably fast (e.g. 66 MHz) 486 processor and 16 Mbytes of memory which is running under Windows 3.1 or later. For computers running Windows 95 a Pentium with 16 Mbytes of memory is recommended as the minimum specification. However, we have run the software successfully on PCs with only 8 Mbytes of memory. About 60 Mbytes of free disk space is required for all the lesson documentation and images. A graphics card which can display 16-bit colour images (High colour) is required to view colour composites. The lessons are available over the World Wide Web (http://www.unesco.bilko.org/) and on CD-ROM.

Lesson texts and other documentation are available as Microsoft Word (.doc) and Adobe Acrobat (.pdf) files, which you can print from disk or edit to suit your specific training and educational needs.

Use of the module: Just one condition and one request are attached to the copying and distribution of the material in this module. The condition is that the material may not be sold. The request is that if you make use of this module, either the original or a copy, you fill in the reply sheet and return it to the UNESCO-Bilko Project Coordinator, c/o ITC, Enschede, at the address indicated. The return of reply sheets helps us to assess whether our modules are reaching the community for which they are intended, and so serves as a guide in preparing new lesson material for future modules. A reply sheet is attached to the letter accompanying this module and it is reproduced on page 185.

Perspective: It is now over ten years since the first memoranda on what has become the Bilko project were circulated. For those of us who have been involved with the project since its inception, it was a pleasure to experience the warm reception accorded the first module and a relief to see the steady growth of the small community of interested teachers and researchers as subsequent modules were published. We now have lessons from all five continents and the present module will be available worldwide over the internet.

With the increasing number of lessons has come an increase in the community which surrounds the Bilko project. The first module was written by the founding group and distributed to colleagues known at UNESCO to be interested in the teaching of marine sciences. Recipients were asked to make copies freely available to colleagues and students, and to consider writing a lesson for publication in a future module. The number, quality and variety of the lessons received are evidence that the recipients are not content merely to use the materials provided, but do indeed think it worth while to contribute to this exercise in improving the quality of teaching.

Since its earliest days, the prime objective of this project has been, by example, to promote excellence in teaching. This is a demanding task, but the reports on existing modules are good. We are aware, however, of two shortcomings relative to the original goals: lessons, while extensively reviewed and edited, have not usually been subjected to the extensive student testing that is normally a prominent feature in the development of computer-based lessons, and the range of topics covered remains narrower than it need be given the power of the existing software.

Development: An initiative is now in hand to extend the concepts developed in the earlier Bilko modules and develop web-based lessons which can be run over the internet. These will build on the concepts embodied in the Windows Help file lessons developed for Module 6, will be easier for lesson creators to write, will retain the advantages of hypertext links, and will offer more interactivity as HyperText Markup Language (HTML) and Java develops.

You too can contribute: One purpose in writing this introduction is to ask your help. The project is open to development along three broad lines which may be described as relating to access, excellence and community. All are asked to take part in this development, but key contributions will come from those who teach their students using the lessons and offer their experience for the benefit of others.

The writing of Bilko for Windows is an important development. We know that their experience in the classroom has led many teachers to add their own questions and refinements to the published lessons. Our objective is to enrich these lessons by pooling the knowledge that already exists in the network of Bilko users. For this, we'd like questions, descriptions of student projects, alternative images and alternative presentations. Please do not hesitate to send exercises, modifications or additional explanations which have worked well with your students. It is a simple matter to link optional text to the main lessons, and we hope to add several tens of exercises to the published versions of existing modules.

All types of lessons are welcomed, provided they are based on data that make use of the Bilko for Windows software. If you would like to contribute a lesson, note that Section 3 of Module 2 contains a "Lesson for Lesson Creators" which provides guidance on the preparation of images and texts. As with most scientific educational literature, contributed lessons are subject to editorial review before publication. To find out more, a useful first step is to fill in the reply sheet at the end of this module. If you would like to discuss the matter informally, do not hesitate to contact any member of the development team.

Other modules: If you find this module interesting and would like to obtain copies of others in the series (written for the MS-DOS version of Bilko), these are downloadable over the internet. See World Wide Web address http://www.unesco.bilko.org/ for further details or write to (or e-mail) the UNESCO-Bilko Project Coordinator, c/o ITC, Enschede at the address given on page 185. The contents tables of these earlier modules can be browsed over the internet at the address above and are also reproduced in Appendix B.

 

Bilko Project Steering Committee

Dr David Blackburn
Pierrelongue
F-26170 Buis Les Baronnies
France
Dr Richard Callison
Pharos Scientific Ltd
East Bankhead, Monikie
DUNDEE DD5 3QG
United Kingdom
Malcolm Dobson
Pharos Scientific Ltd
43 Scott Street
DUNDEE DD2 2AP
United Kingdom
Dr Craig Donlon
CEC - JRC Ispra
Space Applications Institute
Marine Environment Unit
I-21020 Ispra (VA)
Italy
Dr Alasdair Edwards
Department of Marine Sciences and Coastal Management
University of Newcastle
Newcastle upon Tyne NE1 7RU
United Kingdom
Professor John van Genderen
International Institute for Aerospace Survey and Earth Sciences (ITC)
PO Box 6
7500 AA Enschede
The Netherlands
Dr Jesus Morales Cañavate
CICEM "Agua del Pino"
Delegacion Provincial de Agricultura y Pesca
PO Box 104
21071 HUELVA
Spain
Professor Ian Robinson
School of Ocean and Earth Science
Southampton Oceanography Centre
University of Southampton
SOUTHAMPTON SO14 3ZH
United Kingdom
Dr Vitaly Sytchev
Russian State Hydrometeorological Institute
98 Malookhtinsky Avenue
195196 St Petersburg
Russia
Dr Dirk Troost
Environment and Development in Coastal Regions and in Small Islands (CSI)
UNESCO 1, rue Miollis,
75732 Paris Cedex 15,
France

Section 2

 

Practical lessons using coastal image data of the

Caicos Bank

 

 

Applying Remote Sensing to Coastal Management Issues

The lessons in Module 7 are designed to aid the training of remote sensing practitioners in developing countries who are working with coastal images and want to gain the most from their images. The primary aim of the lessons is to promote an understanding of the principles of the various techniques involved and to develop the student’s critical faculties in terms of assessing whether remote sensing technologies are likely to be useful in achieving defined objectives. Some of the lessons are fairly straightforward (Lessons 1, 2 and 6), others guide the student through some complex and difficult areas of image processing (e.g. Lessons 3, 4 and 5), and others introduce relatively simple techniques which are nevertheless at the forefront of applied remote sensing and can greatly enhance the usefulness of imagery to coastal managers (e.g. Lessons 7 and 8).

Lessons 1, 2 and 7 were drafted by Dr Peter Mumby and Lessons 3, 4, 5, 6 and 8 were written by Dr Alasdair Edwards who then edited all the lessons for consistency of style. All lessons drew heavily on chapters from the Remote Sensing Handbook for Tropical Coastal Management (Green, E.P., Mumby, P.J., Edwards, A.J. and Clark, C.D., in press). Specific chapters in the Handbook where the skills learnt in each lesson can be followed up are indicated in the lessons. The lessons attempt to follow a logical sequence of image interpretation and processing.

Thus Lesson 1 allows you to get to know the study area in the Turks and Caicos Islands from where the images were acquired and concentrates on visual interpretation of imagery using colour composites. It also seeks to builds your ability to link what is on the images to actual habitats on the ground (or in the sea!) and to indicate how remotely sensed imagery can be used to guide field survey. Lesson 2 focuses on the importance of acquiring images of an appropriate scale and spatial resolution to meet your objectives. In the lesson you estimate the size of a range of habitats and man-made structures and then discover which image types are suitable for mapping these habitats or structures. Lesson 3 is a specialist lesson and is probably the most complex of all. It explores the radiometric correction of imagery which is necessary if you are trying to monitor change or are just working with more than one image and seeks to show why radiometric correction (including atmospheric correction) is necessary for certain applications and how to carry it out. Lesson 4 is partly included as preparation for Lesson 5 which deals with how one compensates for the effect of water depth on bottom reflectance. It introduces you to the effects of water depth and how its influence on bottom reflectance is such that one can crudely map depth using optical imagery. Lesson 5 then shows you how to compensate for the effect of water depth so that you can map submerged marine habitats with some degree of confidence. This very important processing step is often not done although, for imagery with more than two wavebands which penetrate the water column, it dramatically improves the accuracy of habitat mapping. Lesson 6 takes the outputs of depth-invariant processing covered in Lesson 5 and uses these to illustrate the principles of habitat classification using a simple box-classifier. The Lessons 7 and 8 show how one can quantitatively map seagrass standing crop and mangrove leaf area index (LAI) respectively using satellite and airborne imagery. The relatively simple techniques involved seem under-utilised. They use the same imagery to provide considerable additional information to coastal managers. This makes much better use of the imagery although some additional field survey work is required.

Hopefully, the lessons will stimulate better use of existing imagery and a better understanding of the processing steps required to achieve habitat maps of useful accuracy. The issue of accuracy of outputs is more fully explored in the Remote Sensing Handbook for Tropical Coastal Management.

To carry out the lessons successfully you need to have a good working knowledge of Bilko for Windows (obtainable by working through the Introduction and/or Introductory Tutorials - a few hours work which also serves to introduce you to a range of image processing techniques). Also for many of the lessons, a working knowledge of the spreadsheet Excel (or another Windows compatible spreadsheet) is required. Such knowledge is indispensable for anyone thinking of carrying out remote sensing.

Photographic credits:

A number of photographic images are made available in this module as .GIF files. Photographs were provided by Alasdair Edwards, Edmund Green, Peter Mumby and Jonathan Ridley. Those provided by Jonathan Ridley (Coral Cay Conservation) have image names prefixed with "CCC".

Acknowledgements:

The research that underpins the lessons for this module was funded by the UK Department for International Development's Environment Research Programme. The Turks and Caicos Islands' Department of Environment and Coastal Resources provided invaluable logistical assistance during the field survey work required to ground-truth the images. Our thanks go in particular to Mr Christie Hall, Mr Chris Ninnes, Dr Paul Medley, Mr Perry Seymore, Mr John Ewing, the staff and students of the School for Field Studies, and Ms Angie Ellis for their support in the field.

The module was field tested at the IOC-UNEP Regional Training Course on Seagrass mapping using Remote Sensing held at the Institute of Marine Sciences (IMS), Zanzibar, 24-28 November 1997. We would like to thank Ms Agneta Nilsson, UNEP Water Branch, Nairobi and Dr Julian Barbière, IOC, Paris for their organisation of this workshop and to thank all the Tanzanian and Kenyan participants at the workshop for their enthusiasm and valuable feedback on the module. This feedback from potential users was extremely useful in redesigning some elements of the software and improving the lesson materials. We thank the staff at IMS for their excellent technical support and hospitality which helped ensure the success of the training workshop. For further testing of the software and lessons we are grateful to Mr Mark Busby (Sheffield University), MSc Tropical Coastal Management students (Newcastle University), and members of the Bilko Project Steering Committee.

Comments or suggestions relating to these lessons should be sent to:

Dr Alasdair J. Edwards
Centre for Tropical Coastal Management Studies
Department of Marine Sciences and Coastal Management
University of Newcastle
Newcastle upon Tyne
Fax: +44 (0)191 222 7891 NE1 7RU, UNITED KINGDOM

a.j.edwards@ncl.ac.uk


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