Final Exam (Based on Review on Canvas)

Lecture 6 - 11

How many scans can the ETM+ Optical Chain Scan Mirror do per second?

7 Scans per second

When mapping the vector data, the water sampling location will be mapped as

points

Which sensor among the following has a 12 bit radiometric resolution?

Landsat 8

What is the difference between landsat 8 and 9?

Landsat 8 has 12 bit radiometric resolution while Landsat 9 has 14 bit

The image enhancement technique that produces “contrast rich images” is

principal component analysis

What is the range of band 1 in the Landsat ETM+?

450-515

What is the range of band 2 in the Landsat ETM+?

525-605

What is the range of band 3 in the Landsat ETM+?

630-690

What is the range of band 4 in the Landsat ETM+?

750-900

What is the range of band 5 in the Landsat ETM+?

1550-1750

The enhanced image will look worse than the original image after Low pass filtering. (T/F)

True

What is the range of band 6 in the Landsat ETM+?

10400-12500

What is the range of band 7 in the Landsat ETM+?

2090-2350

What is the range of Pan in the Landsat ETM+?

520-900

Out of Landsat 5, 7, 8, and MODIS, which one has the bands with the highest spatial resolution?

Landsat 8

Normalized Difference Vegetation Index (NDVI) for Landsat 5 image is computed by using which 2 bands?

Bands 4 and 3

For a dense vegetation canopy the SAVI (Soil Adjusted Index) value will be equal to which value?

NDVI

Out of ASTER, Landsat, SeaWIFS, MODIS, and Hyperion which one has the most spectral resolution? Which one has the least?

Hyperion has the most spectral resolution (220 bands) and SeaWIFS has the least (8 bands)

Out of ASTER, Landsat, SeaWIFS, MODIS, and Hyperion which one has the most spatial resolution? Which one has the least?

Landsat has the most (30m) and SeaWIFS has the least (1100m)

Out of ASTER, Landsat, SeaWIFS, MODIS, and Hyperion which one has the most temporal resolution? Which one has the least?

MODIS has the most (2 days) while Landsat and ASTER has the least(16 days)

What is a Whiskbroom?

Scanners that record side to side and record one pixel at a time with several bands simultaneously. It needs 1 sensor per band and requires dwell time of a microsecond

Give examples of a whiskbroom

LANDSAT MSS and TM, AVHRR

Give examples of a pushbroom

SPOT, MOMS

Give examples of a framing camera

RBV (Return Beam Vidicon), 2-D array \n camera (like the latest home video cameras)

What is a pushbroom linear array?

Scanner that records using forward motion and records 1 line at a time, with different spectral bands being recorded simultaneously.

What are framing cameras?

They expose all detectors in a 2d array at the same time, collects the entire frame at one time, and uses millions of detectors with dwell times of milliseconds or longer.

What is prism used for in EM Radiation Splitting?

Uses refraction to separate different wavelengths of light; one per several bands.

What is a transmission filter used for in EM Radiation Splitting?

Transmits only those wavelengths between upper and lower bounds of filter; one per spectral band.

What is a Dichroic mirror used for in EM Radiation Splitting?

reflects short wavelengths, passes long wavelengths; one per several bands.

What are Silicon detectors best operated in?

Operate in visible and NIR wavelength regions; uncooled.

What are Indium Antimonide (InSb) Detectors best operated in?

Best in 1.0-5.0 μm infrared region; cooled

What are Mercury:Cadmium:Telluride (Hg:Cd:Te) detectors best operated in?

best in 8-14 μm region; cooled

What are Quantum Ferroelectric Material detectors best operated in?

about 0.6-25 μm capability; experimental

What is Dark Object Subtraction? (DOS)

removes atmospheric scattering in an image and assumes that the darkest part of an image is black

What is raster data?

A digital picture/representation of an object that’s consisted of only numbers, with each data file values being called pixels (smallest part of a picture).

What is vector data?

It consists of points (x,y coordinate), lines (set of line segments), and polygons (closed line/closed set of lines) that creates vector layers

What are the different resolutions raster data can record?

Spectral Res.

Spatial Res.

Radiometric Res.

Temporal Res.

What is spectral resolution?

wavelength intervals that sensors record (band 1 records 0.45-0.52)

narrow/smaller intervals = fine res

wide/larger intervals = coarse res

What is spatial resolution?

area on ground represented by each pixel (e.g. 80m)

The smaller the number, the finer/better the resolution is

What is radiometric resolution?

number of data file values in each band (e.g. 8 bit goes from 0-255 for each pixel)

What is temporal resolution?

how often a sensor obtains imagery of an area (e.g. landsat can view the same area every 16 days)

What are examples of vector data sources?

\
ArcInfo GENERATE format files

AutoCAD Digital Exchange Files (DXF)

United States Geological Survey (USGS) Digital Line Graphs (DLG)

MapBase digital street network files (ETAK)

U.S. Department of Commerce Initial Graphics

Exchange Standard files (IGES)

U.S. Census Bureau Topologically Integrated

Geographic Encoding and Referencing System files (TIGER)

What are examples of raster data sources?

visible/infrared satellite data

radar imagery

airborne sensor data

scanned or digitized maps and photographs

digital terrain models (DTMs)

What are some advantages of satellite data?

digital data can be transmitted thru radio/microwave comms & stored on magnetic tapes, which can be easily processed by a computer

the same area can be covered on a regular basis for change detection

cost for data acquisition < aircraft data

less chance for distortion in the final image

What do Landsat and spot satellites have in common in terms of characteristics

\-Sun synchronous (data’s collected in the same time of day over same region)

\-both can record electromagnetic radiation in 1 or more bands

\-both can record nadir views

What is band 123 in Landsat Data?

Visible portion of the spectrum

What is band 432 in Landsat Data?

false color composite

Veg = red

Water = navy/black

What is band 542 in Landsat Data?

psuedo color composite

Roads = red

Water = yellow

Veg = blue

What is band 457 in Landsat Data?

reflective infrared portion of spectrum and used in land/water discrimination

What is Band 1 in Landsat TM Data?

Blue

What is Band 2 in Landsat TM Data?

Green

What is Band 3 in Landsat TM Data?

Red

What is Band 4 in Landsat TM Data?

Reflective Infrared

What is Band 5 in Landsat TM Data?

Mid Infrared

What is Band 6 in Landsat TM Data?

Thermal Infrared

What is Band 7 in Landsat TM Data?

Mid Infrared

What are the advantages of spectral ratio imaging?

can better relate images to land spectra

more robust/less environmentally dependent

better separation of composition from grain size effects in rocks and soils

can mix thermal IR with vis/nir ratios

What are the disadvantages of spectral ratio imaging?

Diminishes contrast due to brightness diff. and is noisier than single band images.

What is the Advantage of Spectral Ratioing, after DOS?

gets rid of the shadow/slope factor, leaving chemical composition of the target as the main controller of the resulting spectral ratio image.

What can Temporal ratio imaging do?

consists of time1/time2 ratio image of any spectral parameter, which includes measuring robustness of a spectral parameter and change detection

What is the formula of Temporal Ratios of Spectral Ratios

TRt1,t2 = \[{q(i,j)C(i,j)}t1/{q(i,j)C(i,j)}t2\] \[{p(i)/p(j)}t1/{p(i)/p(j)}t2\]

What is image enhancement?

Improvement of contrast between target and background in the form of a nearly continuous-toned image (each spectral band with 0-255 DN values)

What is decorrelation stretch image?

Inverse form of PC transformation by transforming image to PC space, stretching image in PC space, and transformation of image back to n spectral space

What is principal component transformation?

Image enhancement method for displaying maximum spectral contrast from n spectral bands with 3 primary colors.

What is multispectral classification? (What is unsupervised/supervised classification?)

“Supervised” implies that the user knows a “training set” of pixels on the ground for each of the classes to be categorized.

“Unsupervised” implies no prior knowledge of the ground before classification.

What are the advantages in pc images?

can display data from all n spectral bands in 3 display colors

What are the disadvantages in pc images?

it’s scene dependent and not robust. the different display colors represent different materials in different images.

What are the advantages of classification methods?

It can search for spectrally unique target classes better, count classified pixels automatically, and can cluster vegetation

What are the disadvantages of classification methods?

surface exposure of materials you wish to map aren’t always available

Max Likelihood Algorithm needs several pixels of exposure for each class which isnt always available

Materials grade into one another in area coverage making discrete classes less likely

What’s the formula for NDVI?

(NIR-Red)/(NIR+Red)

Landsat TM: (Band 4 – Band 3) / (Band 4 + Band 3)

What are the advantages of NDVI?

It can monitor seasonal/inter-annual changes in vegetation growth and activity

Ratioing reduces many forms of atmospheric noise

What are the disadvantages of NDVI?

It is highly correlated with Leaf Area Index and is sensitive to canopy background variations

What’s the formula for SR?

NIR/Red

Landsat TM: Band 4 / Band 3

What are the advantages of SR?

SR can enhance the contrast between soil and \n vegetation

What are the disadvantages of SR?

SR is much slower to saturate than NDVI when a \n canopy is very dense and soil/vegetation contrast is reduced by variable soil reflectance

What’s the formula for GNDVI?

NIR - Green / NIR + Green

Landsat TM: (Band 4 - Band 2) / (Band 4 + Band 2)

What are the advantages of GNDVI?

The use of green band in vegetative index was found to be more useful than red band for assessing canopy variation in biomass.

What’s the formula for NDMI/NDWI?

(NIR – Mid IR) / (NIR + Mid IR)

Landsat TM: (Band 4 – Band 5) / (Band 4+ Band 5)

What are the advantages of NDMI/NDWI?

Highly correlated to canopy water content and was closely related to plant biomass and water stress than the NDVI.

What’s the formula for SAVI?

(1+ L) (NIR – Red) / (NIR + Red + L)

\

In the formula for SAVI, what is L?

L varies with vegetation density and it ranges from 0 for very high vegetation cover to 1 for low vegetation cover.

What are the advantages of SAVI?

minimizes the soil brightness variations and eliminate the need for additional calibration for different soils

What is the Algebra change detection technique?

uses methods such as image differencing, image ratioing, and vegetation index differencing

What is the transformation change detection technique?

Reduces data redundancy between bands and \n emphasizes different information in derived \n components and uses PCA

What is the classification change detection technique?

Reduces external impact of atmospheric and \n environmental differences and uses post classification comparison and unsupervised change detection

What is the visual analysis detection technique?

Visually interprets the color composite image to \n identify the changed areas

What is a spatial filter?

a filter where the brightness value in the output image is a function of some weighted average of brightness values located in the input image

What is 2-dimensional convolution filtering?

evaluating weighted neighboring pixel values

What are some examples of convolution masks/kernels?

3x3, 5x5, 7x7, 9x9

What are some characteristics of healthy green vegetation?

chlorophyll absorption bands and atmospheric water absorption bands

In healthy green vegetation, what occurs from 0-0.7 micrometers in wavelength?

leaf pigments (chlorophyll a, b, Beta-carotene, etc)

In healthy green vegetation, what occurs from 0.7-1.3 micrometers in wavelength?

scattering in the spongy mesophyll

In healthy green vegetation, what occurs from 1.3-2.6 micrometers in wavelength?

leaf water content

When it comes to surface impression, what’s the most important part of detecting and identifying things?

making sure the surface isnt disturbed much by human activities and knowing the general area and the nature of the feature

What is one of the key elements of visual interpretation for radar image interpretation?

texture

What are the interpretation elements that are used when interpreting forest cover types

tone, texture, shape, pattern, size, and association

How can floods be predicted using remote sensing?

create topographic models of the glaciers and extensive outwash plains to use as baseline maps for multitemporal change detection and mapping studies