LAB 1: INTRODUCTION TO REMOTE SENSINGuregina.ca/piwowarj/geog309/Lab1.pdf · Geography 309 Lab 1...

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

LAB 1: INTRODUCTION TO REMOTE SENSING

Due Date: September 22

Objectives

To familiarize yourself with:

o remote sensing resources on the Internet

o some remote sensing sensors and their uses

o the course textbook

o the Geomatica image analysis software

Part A: Remote Sensing Resources

There is a wealth of remote sensing information and data on the Internet. In order to help you

become acquainted with some of the available resources on-line, I would like you to find and

document some of them. Two effective ways of looking for information on the Internet are:

use a search engine (e.g. Google); and

look for links to related sites (once you have found one site dealing with your topic area).

Procedure

A1. Find and visit 5 different sites on the Internet that deal with remote sensing.

• None of your 5 sites can come from the same umbrella organization. For example, you

would not be able to count the Departments of Geography and Environmental Systems

Engineering at UofR as two separate sites.

• You cannot include the Canada Centre for Remote Sensing (CCRS) as one of your sites

(since it has already been described for you, below). You are certainly encouraged to

explore the abundance of information available at CCRS, however.

Create a table with the following entries for each site:

Real-World Location Identify the real-word name for this site.

URL Give the Web location of the site's home page.

Brief Description Provide a short description of the data and information available

at this site. You may provide this in point form, but you must be

reasonably descriptive (e.g., don't just say "imagery", say

"Landsat imagery of Western Africa from 1985 to the present").

Question 1: (2 marks) Submit your table of web sites.

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

For example:

Real-World Location URL Brief Description

Canada Centre for Remote Sensing

www.ccrs.nrcan.gc.ca/ccrs/homepg.pl?e

An extensive site containing information on all aspects of remote sensing from a Canadian perspective. On-line information includes:

a comprehensive summary of remote sensing satellites & sensors, including RADARSAT;

current research issues;

education al resources, including an on-line tutorial, remote sensing glossary, and FAQ;

a remote sensing image "tour" of Canada

A2. The text chosen for this course also contains a lot of useful information. Scan through the

text and identify 5 different remote sensing instruments (sensors). For each sensor, list one

application for which the authors suggest it can be used.

Create a table with the following entries for each sensor:

Sensor Remote sensors are frequently identified with both their satellite

name and the sensor name, e.g. Landsat 7 (satellite) Enhanced

Thematic Mapper (sensor) - try to separate the sensor name from

its satellite name.

Satellite sometimes called spacecraft or platform

Application The images in the book are a good source of example

applications.

Question 2: (2 marks) Submit your table of Sensors and Satellites.

For example:

Sensor Satellite Application

Enhanced Thematic Mapper (TM)

Landsat 7 monitoring forest re-growth after logging or burns

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

Part B: Selecting an Image for Class Presentation

One of the requirements for this course is to find a remote sensing image on the Web and present

it to the class. A "suitable" image is one which:

you personally find interesting;

(mostly) fits on one screen without scrolling;

does not originate on the Geography 309 web site;

is not from Google Earth;

you are able to provide the following details:

earth location

URL

satellite name

sensor name

sensor bands or channels shown in the image

image acquisition date

If you are unclear about the suitability of an image, feel free to check with me.

Question 3: (5 marks) Present your image to the class at your scheduled time. Limit your presentation to about 5 minutes. Important:check the on-line course schedule to find out when you are presenting – no marks will be given if you miss your presentation date or fail to hand in your presentation description. You do not need to hand in your presentation description until your actual presentation date.

Image presentations will take place at some time during the lecture period. Presentation marks

will be assigned as follows:

1 mark for having a "suitable" image

this includes providing the requested details (as defined above) about the image

3 marks for a description of the "significance" of the image for:

physical geography; and

human geography.

For your "significance" discussion, you could address such topics as: Did you learn

anything new? Or, How can these data be used by decision-makers? Include at least 3

points for each of the human and physical geography descriptions.

1 mark for your oral presentation:

did you speak loudly, clearly, enthusiastically, and succinctly?

did you try to engage the class in discussion?

Procedure

B1. Search the web and find a remote sensing image suitable for presenting to the class. Be sure

that you can also provide the required details for the image.

B2. Click on the image with the right mouse button and select Save Picture As ... from the pop-

up menu. Save the image to your local disk.

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

B3. Create a description page for your image.

Be sure your page includes:

the image

earth location

URL

satellite name

sensor name

sensor bands or channels shown in the image

image acquisition date

your name, e-mail address, and ID number

the descriptions of the "significance" of the image for physical geography and human

geography.

You may use point form.

B4. At least ONE DAY before you are scheduled to present your image (sooner, if you wish), e-

mail a copy of the image (just your image, not your description page) to me. I will post it on

the course web site for you to access during your presentation.

B5. At the start of class on your presentation day, please hand in a printed copy of your

description page for marking.

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

Example Description

Earth Location Hamilton, Ontario, Canada

URL http://www.city.hamilton.on.ca/Hamilton.jpg

Satellite Landsat 5

Sensor Thematic Mapper

Sensor Channels/Bands Shown in Image

2, 3, 4

Image Acquisition Date September 20, 1985

Geographic Significance (Human)

This is a medium-size city (by Canadian standards).

A large industrial complex is evident by infilling along the south shore of the harbour, as well as piers for large ships.

Shipping might be an important mode of transportation – although no ships are visible, a canal can be seen joining the harbour to the lake.

There does not appear to be much agriculture.

Geographic Significance (Physical)

There are 2 bays/harbours separated from the main lake by natural barriers.

The innermost bay seems to have a lot of suspended sediment (lighter blue colour).

The Niagara Escarpment is visible as a band of trees (shown in red) cutting horizontally across the city.

The land appears to be relatively flat, given the grid layout of the city streets

The strong NIR reflectance suggests that this area receives adequate rainfall to support photosynthetically active plant growth.

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

Part C: Visual Interpretation of Colour Composite Imagery

You will now examine a Landsat Thematic Mapper image of Regina using the PCI Geomatica

Image Analysis System.

Notes

A course disk has been set up where I can put data sets for your use. On the University

computer systems, you will find this disk on the T:\ drive in the folder

\Class\Geography\geog309. Note that it is not necessary to copy the file(s) from this

disk unless I give you explicit instructions to do so.

Tables 1, 2, and 3 (referred to in Questions 3, 4, and 5) are listed at the end of the lab.

You may use Geomatica FreeView for this lab … see the link at the bottom of the course

homepage.

Procedure

C1. From one of the systems in CL 109 click on the PCI Geomatica icon.

C2. In a few moments, the Geomatica toolbar should appear on your screen:

C3. There are many functions available from the toolbar, but in this course we will be primarily

using the Focus image viewer. Focus should start automatically after about 10 seconds when

you start Geomatica, but if it doesn't you can start it by licking once on the left toolbar button

and after a few moments, the Focus window will appear.

C4. Click on the Open File button and a File Selection window will be presented.

a) The image you want to use in this lab is called ReginaTM2010.pix. You will find it on

the Geography 309 course disk.1 Double-click on this file and the image should be

displayed in the Focus window.

C5. You will be looking at a Landsat TM image centred on the City of Regina but also showing

some of the surrounding urban and agricultural areas. This image was acquired on

September 7, 2010.

1 The course disk can be found on your T: drive in the folder \Class\Geography\geog309\.

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

C6. Use the zoom and pan tools (and scrollbars) to move around the image to get a feel for the

software.

C7. Now position your cursor in the middle of the UofR campus and click 2 or 3 times on the

zoom in tool . You should see the campus zoom up in the middle of your screen.

although it may be difficult to distinguish very much, especially if you get too close.

C8. Image displays commonly have 3 basic colours: red, green and blue. Remotely sensed

images may have many more channels. We are interested in exploring different ways of

showing the remote sensing data channels on an image display. Of particular note is that we

can show data acquired in spectral bands which the human eye cannot see in display colours

that we can see.

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

Athough there are many different band combinations possible, the two most common are:

For a true colour composite image,

display the:

For a standard false-colour composite image,

display the:

Sensor's Blue band in display Blue

Sensor's Green band in display Green

Sensor's Red band in display Red.

Sensor's Green band in display Blue

Sensor's Red band in display Green

Sensor's Near IR band in display Red.

Lets change the colour assignments used for the display in order to make the image a little

clearer. Select RGB Mapper… from the Layers menu. In the RGB Mapping window you

will notice 3 columns labeled Red, Green, and Blue corresponding to the three principal

additive colours used by computer monitors to portray colour. Also notice that there is a red

check next to the image layer TM 1, a green check next to the image layer TM 2, and a blue

check next to the TM 3 layer. This is the default method that Focus uses to display colour

imagery. As it turns out, this isn't a very useful combination.

Change the check marks so that TM 4 is shown in red, TM 3 in green , and TM 2 in blue, as

shown in the graphic, below. This, standard false-colour composite, is a common way of

displaying remote sensing imagery. Since we are showing the near infrared band (TM 4) in

red, healthy green vegetation appears red in this image.

Close the RGB Mapping window.

C9. The next step is to brighten the image up a bit by applying a contrast enhancement. You will

learn more about this technique in a later lab, but for now click on the enhancements button

(click on the main part of the button, not on the little downward arrow along its right edge)

.

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

C10. Study the satellite image. You should be able to identify Wascana Lake, the Campus

Green between the Library and the Education buildings, and – with some imagination -

several of the buildings on campus.

C11. Now lets have a look at a true colour composite image of the same data. Create a new

view of the image by clicking on the Launch the Add Layer Wizard button .

C12. When the Add Layer Wizard appears specify that you wish to add an RGB layer and then

click Next >.

C13. Now select the channels you wish to display in Red, Green, and Blue to create a True

Colour Composite image (refer to the table above):

a) Click on the Red button and then select the image channel you wish to show in red;

b) Click on the Green button and then select the image channel you wish to show in green;

c) Click on the Blue button and then select the image channel you wish to show in blue;

d) Click Finish to display the image.

Note that the new layer is drawn on top of your original view thereby obscuring it. You can

toggle back and forth between your colour composites by turning the RGB Layer off and on

(off to show the lower true colour composite; on to overlay the false colour composite). You

change a layers visibility by clicking on its visibility check box:

Further, if you zoom or pan around the image in one colour mode, your actions are

mirrored in the other colour composite.

Question 4: (3 marks) (a) Complete Table 1 for the Landsat TM. (b) Is it possible to create a true colour composite display of SPOT HRV data? Why/Why

not? (c) Is it possible to create a standard false colour composite of SPOT HRV data?

Why/Why not?

Clearly, it is not possible to observe everything about Regina in a Landsat TM image. Table 2 is

a list of the typical types of surface features that we can identify in Landsat imagery (see

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

http://landcover.usgs.gov/classes.php for a description of the feature types). You might also find

the 2010 Field Photographs link on the course website useful for viewing some of the crop

types in Google Earth or Google Maps.

Question 5: (1 mark) Locate and identify good examples of the land covers and land uses listed in Table 2 and describe their tone/colour in each composite image. You may not find examples of every land cover / land use class listed in Table 2 in the image. Only complete the parts of the table that you can see in the image. Refer to http://landcover.usgs.gov/classes.php for a description of each land use / land cover type class.

Question 6: (2 marks) You were able to identify the land use / land cover classes in Table 2 largely because you know Regina and you knew where to find them. How do you think you could find these classes in an area that you were not familiar with?

Question 7: (1 mark) For each Task listed in Table 3, which colour composite image do you think provides the most information? Why do you think so?

Note the annotation along the bottom of the Focus window:

In particular, the cursor location coordinates let you know the current location of your cursor

and the pixel values tell you the pixel data for the channels currently in the display. Note how

these values change as you move your cursor across the screen. The pixel values readings can be

quite useful, but you need to remember which image bands you have loaded into the

corresponding red, green, and blue display channels. If the displayed image in the above

example was a true colour composite Landsat TM scene, then I could read that at the pixel

location (UTM 522500E 5581900N) TM 1 has a value of 15, TM 2 has a value of 12, and TM 3's

value is 12.

If you wanted to navigate to a particular location on your image, you could use the cursor

control button to open a window where you can enter your cursor coordinates directly.

Since the image you are working with has been georeferenced to the Universal Transverse

Mercator (UTM) projection, you can enter locations in UTM coordinates by typing them into the

Geocoded section of the window:

display

scale

display

magnification

cursor location

coordinates

pixel values at the cursor for the

Red, Green and Blue bands

http://landcover.usgs.gov/classes.php


Geography 309 Lab 1

J.M. Piwowar 2010.09.10

Question 8: (4 marks) Use the cursor control panel to position your cursor to the following UTM locations: (a) What is the dark feature at 529000E 5586000N? (b) What is the dark feature at 517700E 5591100N? (c) What is the dark feature at 517000E 5583800N? (d) What is the dark feature at 522500E 5581900N?

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

NAME: ID #

LAB 1: INTRODUCTION TO REMOTE SENSING

Answer Sheets

Due Date: September 22

Question 4: (3 marks) (a) Complete Table 1 for the Landsat TM. (b) Is it possible to create a true colour composite display of SPOT HRV data? Why/Why

not? (c) Is it possible to create a standard false colour composite of SPOT HRV data?

Why/Why not?

Table 1: Common Colour Combinations for Composite Displays

Band Spectral Name [blue, green, red, near IR, middle IR, thermal IR]

True Colour Composite Display Colour [red, green, blue]

Standard False Colour Composite Display Colour [red, green, blue]

TM 1

TM 2

TM 3

TM 4

(b) Is it possible to create a true colour composite display of SPOT HRV data? Why/Why

not?

(c) Is it possible to create a standard false colour composite of SPOT HRV data? Why/Why

not?

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

Question 5: (1 mark) Locate and identify good examples of the land covers and land uses listed in Table 2 and describe their tone/colour in each composite image. You may not find examples of every land cover / land use class listed in Table 2 in the image. Only complete the parts of the table that you can see in the image. Refer to http://landcover.usgs.gov/classes.php for a description of each land use / land cover type class.

Table 2: Surface Feature Appearance in Two Common Colour Composite Displays

Land Cover / Land Use True Colour Composite

Standard False Colour Composite

1 Water

11 Open Water

12 Perennial Ice/Snow

2 Developed

21 Low Intensity Residential

22 High Intensity Residential

23 Commercial/Industrial/Transportation

3 Barren

31 Bare Rock/Sand/Clay

32 Quarries/Strip Mines/Gravel Pits

33 Transitional

4 Forested Upland

41 Deciduous Forest

42 Evergreen Forest

43 Mixed Forest


Geography 309 Lab 1

J.M. Piwowar 2010.09.10

5 Shrubland

51 Shrubland

6 Non-Natural Woody

61 Orchards/Vineyards/Other

7 Herbaceous Upland Natural/Semi-natural Vegetation

71 Grasslands/Herbaceous

8 Herbaceous Planted/Cultivated

81 Pasture/Hay

82 Row Crops

83 Small Grains

84 Fallow

85 Urban/Recreational Grasses

9 Wetlands

91 Woody Wetlands

92 Emergent Herbaceous Wetlands

Question 6. (2 marks) You were able to identify the land use / land cover classes in Table 2 largely because you know Regina and you knew where to find them. How do you think you could find these classes in an area that you were not familiar with?

Geography 309 Lab 1

J.M. Piwowar 2010.09.10

Question 7: (1 mark) For each Task listed in Table 3, which colour composite image do you think provides the most information? Why do you think so?

Table 3: Applications of Colour Composite Displays

Task

Which Composite

Image is Better?

Why do you Think So?

differentiating water from land

delineating the residential street network

differentiating the built environment from the natural environment

Question 8: (4 marks) Use the cursor control panel to position your cursor to the following UTM locations: (a) What is the dark feature at 529000E 5586000N? (b) What is the dark feature at 517700E 5591100N? (c) What is the dark feature at 517000E 5583800N? (d) What is the dark feature at 522500E 5581900N?

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