Module EGM310

Introduction to Remote Sensing and GIS

Module structure Part 1: Geographical Information Systems (GIS) (weeks 1-4) Part 2: Underwater Remote Sensing (weeks 5-8) Part 3: Terrestrial Remote Sensing (GIS) (weeks 9-12)

Aims – URS component of EGM310 1. To examine the principles and methodology of underwater acoustics as applied to seafloor surveying and exploration; 2. To undertake the processing, integration and interpretation of seafloor data; 3. To demonstrate the range of industrial and academic applications of underwater acoustics, and 4. To develop a range of key skills including numeracy, problem solving, presentation and communication appropriate to this area.

Learning outcomes On successful completion of this module you should be able to: 1.  Understand the basic theoretical concepts behind underwater

acoustics;

2. Understand the techniques for the acquisition, processing and interpretation of seabed and sub-surface acoustic data, and 3. Successfully integrate a diverse set of marine geological and geophysical data for the solution of an academic/industrial problem.

A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographically referenced data – used for the spatial mapping and integration of remote sensing data.

Remote sensing is the acquisition of information about an object or phenomenon, without making physical contact with the object. In modern usage, the term generally refers to the use of aerial or underwater sensor technologies to detect and classify objects on Earth by means of propagated signals (e.g. electromagnetic radiation emitted from satellites or acoustic energy transmitted from sonars on ships).

Year 1 EGM101 Skills Toolbox

Year 2 Introduction to GIS and Remote Sensing

Year 3 Advanced GIS

Year 3 Seafloor Mapping

EGM310 Introduction to Remote Sensing and GIS

Lecture Principles of Underwater Acoustics

Geological)Survey)of)Norway,)2004)

Joint Irish Bathymetric Survey (JIBS): 319GB

Background

•  How do we generate these maps of the seafloor?

•  To obtain an image of the seafloor, we need to illuminate or irradiate the study area with an appropriate radiation.

•  To get sufficient returned radiation, its absorption by the environment needs to be small.

•  A practical and simple definition to compare the various types of radiation regarding their individual absorption by seawater is the penetration depth.

Satellite Remote Sensing concentrates on electromagnetic sources for remote sensing.

Why use acoustics for underwater imaging?

Wille, 2005

ADUSurvey,+2006+

Seafloor+scar+off+Sumatra+more+than+10km+

wide+which+resulted+from+the+magnitude+9+

quake+that+occurred+on+December+26th+2004+

(Klein,+2006).++

Iceberg+scour+marks+(Klein,+2006).++ Two+bodies+laying+on+a+Swiss+lake+boKom+

(Klein,+2006).++

MulMbeam+sonar+image+of+a+rocky+reef+at+Stanton+banks+(Brown,+2006).+ Pipeline+(Klein,+2006).++

The acoustic solution •  Echo-sounding from nature – bats and dolphins.

The recent success of marine sonar as an imaging tool is due to:

•  precise global positioning satellite navigation (GPS);

•  advanced computer and data storage capability, and

•  high-tech transceiver hardware.

Historical context

•  World War I – early sonar systems developed by the American, British, and French, were used to find both submarines and icebergs. They were called ASDICs (named for the AntiSubmarine Detection Investigation Committee). These early units were crude if not effective.

•  1925-1927 Grosse Atlantische Expedition German research vessel RV Meteor – ship crossed the Atlantic 13 times in 2 years at 600km line-spacing.

•  World War II - underwater acoustics developed and enemy submarines could be detected more easily by surface ships as they sent a stronger and better formed sound pulse into the water. The pulse would bounce off the submarine's hull and give away their distance from the surface ship.

•  Sonar (an acronym for SOund NAvigation and Ranging), became very important for the detection of the submerged enemy.

•  20th Century - the development of underwater acoustics has brought forth essentially four lines of echo-sounder evolution, stimulated by various emerging applications: the multi-beam echo-sounder (MBES), the side-scan sonar (SSS), the sub-bottom profiler (SBP) and the acoustic doppler current profiler (ADCP).

Klein Associates, 2006

Part 2: Underwater Remote Sensing – assessment

Assignment Underwater cable route selection (33% of module)

[1] Introduction   •  You are an independent consultancy, employed by the Northern

Ireland Environment Agency (NIEA), to recommend a low impact route for a submarine cable from Rathlin Island to Ballycastle.

•  As part of the Government’s commitment to renewable energies, a proposed wind farm is to be located on Rathlin Island.

•  The power scheme is designed to feed electricity to towns in County Antrim. The first supply town on the route is Ballycastle, where the cable makes landfall.

•  NIEA are concerned that the cable route should have minimum impact on the natural and cultural landscapes, in line with EU policy.

•  Your consultancy company is therefore tasked with selecting and justifying a suitable marine cable route (from Rathlin Island to Ballycastle) on the basis of the spatial integration and interpretation of existing marine remote sensing data sets.

 

•  All relevant data sets will be distributed via dropbox and will be introduced and discussed in the practical sessions.

•  You are expected to build your own GIS project from these data (from week 1) during the practical sessions and use this as a decision-making tool.

To achieve a good mark in this assignment (33% of the module), it is therefore essential that you: •  have completed all GIS practicals in weeks 1-4, and

•  that you attend and actively participate in all practical sessions in weeks 5-8.

[2] Group or solo work   •  You should complete the assignment in a group of 2 - you are

responsible for picking and managing your own groups.

•  When submitting the assignment, ensure you include a cover sheet on the front-page of the report that clearly lists members of the group.

•  I suggest therefore you work in your groups in the practical sessions.

•  Weeks 5-8: Practicals will begin at 14.15 in G096

[3] Guidelines   Submission deadline The final report should be submitted to Euan Dawson in the ORC no later than 4:00pm on Thursday of Week 9. Late submissions may be awarded a mark of zero.   Figures All GIS-derived maps and figures in the report should be professionally produced, clearly structured and contain accurate scale bars, graticules, keys, north arrows etc.. Marks will be deducted for omission of these elements. Figures (and tables) should be numbered in order of appearance and should be accompanied by detailed figure captions – of sufficient detail that the figure and caption can stand alone from the main text.   Word count The report should have a maximum of 750 words. This word count does not include figure captions or references. Marks will be deducted for excessive word counts.  

Given that a sub-sea cable will be installed on the seafloor between Church Bay on Rathlin Island and Ballycastle on the north coast of Ireland, the report should clearly outline and justify your chosen cable route using the following guidelines:   •  Installation of the cable will involve trenching to a maximum depth of

2m and post-installation backfilling of the trench. •  The route must avoid all shipwreck sites, as much bedrock as possible,

slopes exceeding 40 degrees and mobile substrates exceeding mean spring flows of 50cms-1.

•  The proposed route, with a 50m buffer, should be clearly illustrated on a map using the bathymetric and/or backscatter data for context.

  It is up to you to decide what maps, figures, text and numbers you think are appropriate to include in the report. Remember – you are dealing with quantitative spatial data, so please quantify as much as possible in the report.

Marking scheme

Maps (20%) Bathy data analysis (20%) Backscatter data analysis (20%) Wreck data analysis (10%) Route justification (10%) Presentation (10%) Referencing (10%)