GIS and Remote Sensing Katerina Tzavella Project Researcher PhD - - PowerPoint PPT Presentation

GIS and Remote Sensing

Katerina Tzavella

Project Researcher – PhD candidate

Technology Arts Sciences TH Köln – Technische Hochschule Köln Institute of Rescue Engineering and Civil Protection Betzdorfer Straße 2 50679 Köln T: +49 221-8275-2354 F: +49 221-8275-2202 E-Mail: katerina.tzavella@th-koeln.de Web: https://riskncrisis.wordpress.com/the-team/tzavella_katerina/ Spring School Land use and the vulnerability of socio-ecosystems to climate change: remote sensing and modelling techniques

Overview

GIS Geographical Information Systems

Raster data

Vector data DEM

(Digital Elevation Model)

Satellites Remote Sensing

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What is G I S ?

Geographic

+

Information + Systems

Katerina Tzavella | Risk and Crisis management

Katerina Tzavella | Risk and Crisis management

VIDEO

GIS

Is an organised collection of : 1. Hardware 2. Software 3. Network 4. Data 5. Procedures and 6. People!

Visualize Analyze Plan Store Information Decision Making Collect More Map

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With GIS :

put important

information

• f the real world
• n maps…

Geographical features

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Representing Geographical Features

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How do we describe geographical features?

• by recognizing two types of data:

– Spatial data which describes location (where) – Attribute data which specifies characteristics at that location (what, how much, and when) How do we represent these digitally in a GIS?

• by grouping into layers based on similar characteristics and

using either: – Vector Data – Raster Data

The discrete object view represents the real world as objects with well defined boundaries in empty space

(vector data)

 country borders  land parcels  locations  streets

The field view represents the real world as a surface divided into a regular grid of cells. They are continuous surfaces of data. (raster data)

 aerial photograph  a satellite image  a surface of chemical concentrations  an elevation surface.

(x1,y1) Points Polygons Lines

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Representing Geography

Point Line Polygon Vector Raster

Raster data are described by a cell grid, one value per cell Zone of cells

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Katerina Tzavella | Risk and Crisis management

Raster and Vector Data

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Katerina Tzavella | Risk and Crisis management

Cities Rivers Roads Lakes States

17

Information is organized into layers

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Many ways to use GIS in the real-world!

Carbon Management Aviation Safety Energy Forecasting Agricultural Efficiency Disaster Management Public Health Community Growth Homeland Security Coastal Management Invasive Species Water Management Air Quality Katerina Tzavella | Risk and Crisis management

Remote sensing (RS) is the collection of information about an object without being in direct physical contact with the object.

What is Remote Sensing?

• 1. Energy Source or Illumination (A)
• 2. Radiation and the Atmosphere (B)

3. Interaction with the Object (C)

• 4. Recording of Energy by the Sensor (D)
• 5. Transmission, Reception and Processing (E)

6. Interpretation and Analysis (F)

• 7. Application (G)

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Electromagnetic Radiation (EMR)

Remote sensing is concerned with the measurement of EMR returned by the earth’s natural and cultural features that first receive energy from the sun or an artificial source such as a radar transmitter.

Wavelength Frequency (how many times peak passes per second)

Light - can be thought of as a wave in the 'electromagnetic field' of the universe A wave can be characterized by its wavelength or its frequency

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• Because different objects return different types and amounts of

EMR, the objective in remote sensing is to detect these differences with the appropriate instruments (sensors).

• This makes it possible for us to identify and assess a broad range
• f surficial features and their conditions.

The Electromagnetic (EM) Spectrum

Electromagnetic Radiation (EMR)

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Sensors

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Sensors

Active Sensors

• LIDAR
• RADAR

Passive sensors

• Landsat
• ASTER
• Quickbard
• Ikonos

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Platforms

Platforms are:

• Ground based
• Airborne
• Spaceborne

Sensing from 1 meter to 36,000 km height

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Aerial Camera

Multispectral Satellite Radar Satellite (SAR) Hyperspectral Sensor

Landsat/Ikonos/Quickbard

Hyperion

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Application of Remote sensing

22

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• Urbanization & Transportation

– Updating road maps – Asphalt conditions – Wetland delineation

• Agriculture

– Crop health analysis – Precision agriculture – Compliance mapping – Yield estimation

Natural Resource Management

 Habitat analysis  Environmental assessment  Pest/disease outbreaks  Impervious surface mapping  Lake monitoring  Hydrology  Landuse-Landcover monitoring  Mineral province  Geomorphology  Geology 23

National Security

• Targeting
• Disaster mapping and monitoring
• Damage assessment
• Weapons monitoring
• Homeland security
• Navigation
• Policy

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What is a Digital Elevation Model (DEM)?

Devil’s Tower in Wyoming

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Katerina Tzavella | Risk and Crisis management

a. By digitizing contours

This is a ‘second hand’ digital, as contours are abstract and may result in ‘artifacts’ in the model.

b. Digital stereo photogrammetry

This is a better option, as it refers to the real surface captured from aerial photographs.

b. Direct image grid DEM from satellites / radars

U.S. Releases Enhanced Shuttle Land Elevation Data through the Shuttle Radar Topography Mission SRTM

DEM creation

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Shuttle Radar Topography Mission SRTM

• The Shuttle Radar Topography Mission produced the most

complete and highest resolution digital elevation model of the Earth.

• The project was a joint endeavor of NASA,

the National Geospatial-Intelligence Agency, the German and Italian Space Agencies, and flew in February 2000.

• It used dual radar antennas to acquire data

processed to digital topographic data of very good resolution.