Podcast
Questions and Answers
What type of map displays the numerical aspect of spatial data?
What type of map displays the numerical aspect of spatial data?
Which of the following is NOT a method of representing map scale?
Which of the following is NOT a method of representing map scale?
What is a limitation of a map compared to a globe?
What is a limitation of a map compared to a globe?
An Isopleth map typically represents which of the following?
An Isopleth map typically represents which of the following?
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Which of the following is a correct example of a verbal statement scale?
Which of the following is a correct example of a verbal statement scale?
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What is the first requirement for remote sensing to function effectively?
What is the first requirement for remote sensing to function effectively?
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Which of the following best describes the interaction of energy with the atmosphere during remote sensing?
Which of the following best describes the interaction of energy with the atmosphere during remote sensing?
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What is the role of a sensor in remote sensing?
What is the role of a sensor in remote sensing?
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Which software is NOT mentioned as a tool for remote sensing and GIS?
Which software is NOT mentioned as a tool for remote sensing and GIS?
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The process of transforming recorded energy into usable data occurs during which phase?
The process of transforming recorded energy into usable data occurs during which phase?
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What does the term 'radiation and the atmosphere' imply in remote sensing?
What does the term 'radiation and the atmosphere' imply in remote sensing?
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What is the first stage in the remote sensing process?
What is the first stage in the remote sensing process?
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What type of classification is used to identify land cover with known categories?
What type of classification is used to identify land cover with known categories?
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Which of the following is true regarding the interaction of energy with the target?
Which of the following is true regarding the interaction of energy with the target?
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Which method is NOT considered active remote sensing?
Which method is NOT considered active remote sensing?
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What does the process of application in remote sensing involve?
What does the process of application in remote sensing involve?
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In data acquisition, which of the following is an example of in situ measurement?
In data acquisition, which of the following is an example of in situ measurement?
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What is the ultimate purpose of data analysis in the remote sensing process?
What is the ultimate purpose of data analysis in the remote sensing process?
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Which type of remote sensing does NOT utilize reflected or emitted electromagnetic energy?
Which type of remote sensing does NOT utilize reflected or emitted electromagnetic energy?
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What is the correct sequence of converting energy into a usable form described in the remote sensing process?
What is the correct sequence of converting energy into a usable form described in the remote sensing process?
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What aspect contributes to different terrain objects producing varied electromagnetic responses?
What aspect contributes to different terrain objects producing varied electromagnetic responses?
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What is one of the primary advantages of using GIS?
What is one of the primary advantages of using GIS?
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Which of the following components is NOT a key component of a GIS?
Which of the following components is NOT a key component of a GIS?
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In GIS, which type of data is primarily used to differentiate it from other information systems?
In GIS, which type of data is primarily used to differentiate it from other information systems?
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Which aspect of GIS involves the integration of spatially referenced data?
Which aspect of GIS involves the integration of spatially referenced data?
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Which of the following fields does NOT contribute to the development of GIS?
Which of the following fields does NOT contribute to the development of GIS?
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According to Burrough (1986), what capability does GIS provide?
According to Burrough (1986), what capability does GIS provide?
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What characterizes the data collection in GIS compared to other systems?
What characterizes the data collection in GIS compared to other systems?
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Which function of GIS involves the systematic organization of data?
Which function of GIS involves the systematic organization of data?
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What is the primary function of the Eliminate operation?
What is the primary function of the Eliminate operation?
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What does the Dissolve operation achieve?
What does the Dissolve operation achieve?
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What is a characteristic of the Buffer operation?
What is a characteristic of the Buffer operation?
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Which of the following processes does spatial modeling involve?
Which of the following processes does spatial modeling involve?
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When is the Eliminate command particularly useful?
When is the Eliminate command particularly useful?
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Which statement best describes incremental buffers?
Which statement best describes incremental buffers?
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What is one outcome of using the Dissolve operation on polygons?
What is one outcome of using the Dissolve operation on polygons?
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In the context of Buffer operations, which type of buffer can be created?
In the context of Buffer operations, which type of buffer can be created?
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What is the role of pixel values in raster data?
What is the role of pixel values in raster data?
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How is location typically identified in a raster dataset?
How is location typically identified in a raster dataset?
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What happens when two classes run across the middle of a pixel?
What happens when two classes run across the middle of a pixel?
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Which of the following best describes the function of arithmetic operations in raster data?
Which of the following best describes the function of arithmetic operations in raster data?
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What is the purpose of the regrouping operation in raster GIS?
What is the purpose of the regrouping operation in raster GIS?
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What type of display method is the simplest in raster GIS?
What type of display method is the simplest in raster GIS?
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In what situation are values in pixels coded as integers explored in raster data?
In what situation are values in pixels coded as integers explored in raster data?
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Which statement is true regarding the storage requirements of raster data?
Which statement is true regarding the storage requirements of raster data?
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Study Notes
Remote Sensing and GIS
- Remote sensing is the science of acquiring information about the Earth's surface without physical contact.
- It involves sensing and recording reflected or emitted energy.
- Remote sensing processes include: illumination source, radiation from atmosphere, interaction with the target, recording of energy by the sensor, transmission, reception, processing, interpretation and analysis and application.
- Remote sensing has applications in agriculture, bathymetry, cartography, climatology, coastal erosion, disaster monitoring, forestry, glaciology, geology, oceanography, meteorology, pollution monitoring, and snow resources. It is used for urban mapping, infrastructure/construction management, and water resources mapping and monitoring.
Outline of talk
- Part One: Basics of Remote Sensing and GIS
- Part Two: Applications of Remote Sensing and GIS
Resolutions
- Spatial Resolution: measure of detail in an image, how closely lines can be resolved.
- Spectral Resolution: width of the spectral band.
- Radiometric Resolution: fineness of representing intensity differences. Expressed in bits.
- Temporal Resolution: revisit time.
Software for RS and GIS
- ERDAS Imagine
- PCI Geomatica
- Idrisi (for window)
- GRASS
- ENVI
- ILWIS
- MapInfo
- Arc GIS
- QGIS
- Intergraph
- GRAM++
Stages in Remote Sensing
- Electromagnetic energy reflected/emitted by Earth surface features
- Received by remote sensors
- Converted to electrical signals
- Converted to digital form
- Transmitted to ground station
- Organized data on CDs/DVDs
- Distributed to users
- Analyzed by users producing information
Remote Sensing Process
- Problem Statement
- Data Acquisition
- In-situ measurements (GPS, biomass, soil moisture, spectro-radiometer, etc.)
- Remote Sensing Data (passive and active remote sensing)
- Data Analysis
- Visual interpretation
- Digital Image Processing
- Scientific Visualization
- Information Presentation
Basis of Remote Sensing
- Different terrain objects/phenomena radiate/reflect electromagnetic energy differently at different wavelengths.
- Interaction with terrain features generates multispectral responses at different wavelengths.
- Images are available with various resolutions for different purposes.
Orbits of Satellites
- Polar orbit: altitude ~705 km (nominal)
- Inclination - 98.2˚
- Time of Day-9:45 A.M
- Orbit period - 98.9 min
- Geo-Synchronous Orbit: 36000 km
- Spectral bands VIS 0.55-0.75 μm, IR 10.5-12.5 μm.
- Resolution at sub-satellite point: VIS 2 km, IR 8 km.
- Data rate: 526.5 kbs
Digital Image Processing
- Image rectification: geometric correction
- Image enhancement: contrast manipulation
- Image classification: supervised/unsupervised classification, NDVI (NIR-Red/(NIR+Red))
- Post-classification smoothing: majority filter
- Accuracy assessment: Kappa coefficient
Steps in Digital Image Processing
- Image Acquisition
- Image Corrections
- Image Enhancement
- Feature Selection
- Image Transforms
- Final Interpretation
Data Sources in GIS
- Analog Maps
- Topographic Maps
- Aerial Photographs
- Satellite Images
- Ground Surveys
- Ground Surveys with GPS
- Government of India - Primary Survey Depts.
- State Government - Primary Survey Depts.
- City, Town, and Village level maps and Records
- Reports and Publications
What Does a GIS Do?
- Location - What is at a given location?
- Condition - Where does it occur?
- Routing - What is the best way?
- Trend - What has changed?
- Pattern - What is the pattern?
- Modeling - What happens if?
Reasons for Success of GIS
- Great proliferation of information about cultural and natural environments.
- Remote sensing satellites and other data sources provide large amounts of digital data with geographical references.
- High commercial applications.
- Addresses global, national, local, social and scientific problems.
- Rapid reduction of computer hardware and software costs.
Development of GIS Applications
- Initial phase: assembling, organizing and understanding inventories. (e.g., forest resources maps, soil types, utility networks)
- Second phase: data queries, e.g., location questions, condition questions, and simple analyses
- Third phase: decision support systems for complex analytical operations involving several layers and statistical/spatial techniques. (e.g. determining land suitability for a retail store or monitoring regional changes).
GIS Data Model
- Data Model - set of guidelines for logical representation of data, consisting of logical units and relationships.
- Raster Model - divides study area into regular grid cells (e.g., soil layers, elevation)
- Vector Model - represents features (points, lines, or polygon areas) using coordinates.
Typical Spectral Reflectance curve
- For water, vegetation, and bare soil. Reflectance (%) plotted against Wavelength (µm).
Other Relevant Information
- Flood Simulation: showing flood stages (e.g., 1 m, 2 m, 3 m, 4 m, 5 m, 6 m, 8 m, 10 m, 12 m, 14 m, 16 m)
- Thermal infrared image: obtained using a linescanning radiometer (e.g., 8-13 micron band).
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