Hello Earth! › files › NAGT... · Homework 3 — Data analysisFRS 135, LAB 04 ilillianw, 1 of 1...

Hello Earth!

A grounded introduction to Matlab

Frederik J SimonsChristopher Harig

Adam C. Maloof

Princeton University

(Enter teacher) i

Something canny Matlab can do i

100 200 300 400 500 600 700 800 900 1000

200

400

600

800

1000

100 200 300 400 500 600 700 800 900 1000

200

400

600

800

1000

Something cunning you can do i

The extreme basics — I i

1. help


1. help

2. lookfor


1. help

2. lookfor

3. type


1. help

2. lookfor

3. type

4. who, whos


1. help

2. lookfor

3. type

4. who, whos

6. diary

The extreme basics — II i

7. plot


7. plot

8. xlabel,ylabel,title


7. plot


11. hold on, hold off


7. plot



13. sprintf


7. plot



13. sprintf

14. print


7. plot



13. sprintf

14. print

15. load, imread

Props i

Name Function Exampleimread Reads an image file ix=imread('filename');fullfile Constructs a valid path name ff=fullfile('dirn','fname');size Queries the size of a variable s=size(ix);plot Plots (x, y) values on a graph x=[1 2 3]; y=[10 20 30];

plot(x,y,'o')xlabel Uses a quoted string for an x-axis label xlabel('elevation [m]')ylabel Uses a quoted string for a y-axis label xlabel('roughness')hold on Keeps current axes for next time you plot anything x=[1 2 pi]; y=[10 20 30];

plot(x,y,'bo'); hold on;plot(10*x,3*y,'rs')

linspace Makes an array of N evenly spaced values x=linspace(-3,3,100)between a and b

reshape Changes the dimensions of an array x x=linspace(-3,3,100);to a rows and b columns xr=reshape(x,20,5)

hist Makes a histogram (and plots it) x=linspace(-3,3,10);hist(x)

bar

axis xy

axis ij

Table 1: List of Matlab commands and their function and usage examples.

1

The extreme basics — III i

Addressing:rows, columns, dimensions, range



17. size



17. size

18. transpose



17. size

18. transpose

19. colon



17. size

18. transpose

19. colon

20. linspace



17. size

18. transpose

19. colon

20. linspace

Logic:logical, character, string, double



17. size

18. transpose

19. colon

20. linspace

Logic:logical, character, string, double

21. <, >, ==, ∼, &, |

Going commando i

0 500 1000 1500 2000 2500 3000 3500 4000 4500 500040

60

80

100

120

140

160

180anything 3

column dimension

row

dim

ensi

on

Walkthrough i

colo

r

I, Frederik Simons, am plotting H1W−18.35−test2.jpg

grey

grey

500 550 600 650 700 750 800 850 900 950 1000

diff(

grey

)

Script! i

0 100 200 3000

0.5

1

1.5

2

2.5

3

3.5

4

4.5x 10

6

0 100 200 3000

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5x 10

6

0 100 2000

1

2

3

4

5

6x 10

6

Homework 1 i

Navigate to Course Materials, Software Installation and Templates.

1. Install Matlab as per the instructions.

2. Start Matlab: you will be making a Very Simple Plot.

3. Create ("edit") a new code (*.m) file called "lab01b.m" and in it,

type the following few instructions, or some slight variations

thereof, according to your taste (i.e. vary the numbers):

x=linspace(0,pi,100);

A=1; B=3; f1=0; f2=0;

y1=A*sin(x+f1); y2=B*cos(x+f2); y3=y1+y2;

figure (1)

plot(x,y1,’r’); hold on; plot(x,y2,’g’); plot(x,y3,’b’)

title(’yournetidl01b’)

hold off; axis tight

print(’-dpdf’,’yournetidl01b’)

4. Save this file, see that you can find it again.

5. In step 3, "yournetid" is once again your Princeton netid of course.

6. Now "run" or "execute" this "script" and make sure that something

pops up on your screen - and that a PDF gets made!

7. Find the PDF that you just made (’yournetidl01b.pdf’).

That is your second Assignment! Upload it to Blackboard by the deadline.

Homework 1 i

0 0.5 1 1.5 2 2.5 3 3.5−3

−2

−1

0

1

2

3

4yourpuidl01b

Code hygiene i

1. “If you type it twice, you need to use a variable”

Code hygiene i


2. “If you say it in the absolute, you need to reformulate to the relative”

Code hygiene i



3. “Annotate all graphs completely, and give them meaningful names ”

Code hygiene i




4. “Annotate all code completely, to a ridiculous degree”

Code hygiene i





Documentation/Help/Date

Code hygiene i






Input/Output

Code hygiene i






Input/Output

Computation/Algorithm

Code hygiene i






Input/Output


Figures/Embellishment

Code hygiene i






Input/Output


Figures/Embellishment

Variable Output

Homework 2 — Data collection i

0 50 100 150 200 250 300 3500

50

100

150

200

250

300

350

easting [m] from 528927 in UTM zone 18

north

ing

[m] f

rom

446

6190

in U

TM z

one

18Adrian’s GPS data, their means ±2 standard deviations

CP1CP2CP3CP4CL5

Homework 2 — Data curation i

0 50 100 150 200 250 300 350

0

50

100

150

200

250

300

350

easting [m] from 528927 in UTM zone 18

nort

hing

[m] f

rom

446

6190

in U

TM

zon

e 18

Adrian’s GPS data, their means ±2 standard deviations

CP1CP2CP3CP4CL5

Homework 3 — Data analysis i

FRS 135, LAB 04 lillianw, 1 of 1

TRANSVERSE DUNES IN THE SYRIA PLANUM, MARS1

Motive. By examining transverse dunes on Mars, an environment without disruptive elements such as water and2

vegetation, we can draw conclusions about the initial processes of transverse dune formation on Earth. More3

specifically, we investigate why higher degree slopes correspond with shorter transverse dune wavelengths and4

higher amplitudes.5

Hypothesis . Shorter dune wavelengths appear on steeper slopes because winds are not able to travel far6

before touching the ground and depositing sediment; higher dune amplitudes occur on steeper slopes because7

the distance of the slope to the boundary layer decreases at a quicker rate, resulting in higher velocity sediment-8

carrying winds that can carry and deposit more sediment.9

180 200 220 240

Ele

vatio

n [m

]

6152

6154

6156

6158

6160

A

Meters East230 240 250 260 270 280 290 300

Ele

vatio

n [m

]

6154

6156

6158

6160

B

Dune Wavelength [m]5 10 15 20 25 30

Cou

nt

0

1

2

3

4

5

6A

6B

AB

Bright Dunes in the Syria Planum

Meters0 50 100 150 200 250

Met

ers

0

50

100

150

200

250

Ele

vatio

n [m

]

0

2

4

6

8

10

12

14

16

Figure 1: Transect A crosses 8 transverse dune peaks and transect B crosses 6 dune peaks . Transect B follows a steeperslope than transect A. The average dune wavelength found along transect B was 7.54m; along transect A the average dunewavelength was 12.47m. The average dune amplitudes (not shown in figure) were 1.02m for transect B and 0.82m fortransect A. Image was downloaded from < htt p : //www.uahirise.org/dtm/dtm.php?ID = ESP0328141670>

Acknowledgements. Thank you to Chris Harig, Adam Maloof, and Amber Yin for their help with figure10

drafting in Matlab, and to Gene Li for assiting with the image download.11

Homework 3 — Data analysis iFRS 135, LAB 04 gretam, 1 of 1

INTRA-CRATER DUNES IN IAXARTES THOLUS, MARS1

Motivation. Studying digital elevation models of dunes on Mars can lead to insights about the surface and2

weather on Mars.3

Hypothesis. As the elevation of the dunes in Iaxartes Tholus increases, the dunes increase in size (wavelength4

and amplitude), possibly due to a more abundant sand supply.5

Meters East0 500 1000 1500 2000 2500

Ele

vatio

n [m

]

0

50

100

150

200

A

Meters East0 500 1000 1500 2000 2500

Ele

vatio

n [m

]

0

50

100

150

200

B

Elevation [m]0 50 100 150 200

Dun

e W

avel

engt

h [m

]

0

100

200

300

400

500

600

700

AB

A

B

Intra-Crater Dunes in Iaxartes Tholus, Elevation offset = -5982.44 m

Meters East0 500 1000 1500 2000 2500 3000 3500

Met

ers

Sou

th

0

500

1000

1500

2000

2500

Ele

vatio

n [m

]

0

20

40

60

80

100

120

140

160

180

200

Figure 1: Intra-crater dunes in Iaxartes Tholus vary with elevation. Transect lines show increasing wavelength and amplitude as the elevation increases.Digital elevation model came from http://www.uahirise.org/dtm/dtm.php?ID=ESP_018938_2520.

Acknowledgements. Thank you to Gene Li, Joanna Zhang, Bruce Allen, Devin Blake Kilpatrick, Chris6

Harig and Adam Maloof who helped with figure drafting.7

Homework 3 — Data analysis iBRUCE ALLEN, LAB 04 brucema, 1 of 1

DARK DUNES IN HERSCHEL CRATER OF MARS1

Motivation. Mapping and analyzing sand dunes on Mars allows humans to better understand the environment2

of a place that they’ve yet to step foot on.3

Hypothesis. Based on the geometry in figure 1, the transected dunes are Barchan dunes.4

A

B

Dark Dunes in Herschel Crater of Mars

Meters0 500 1000 1500

Met

ers

0

500

1000

1500

2000

2500

3000

Elev

atio

n [m

]

0

10

20

30

40

50

0 100 200 300 400 500

Elev

atio

n [m

]

0

10

20

30

40

50

A

Meters East0 100 200 300 400 500

Elev

atio

n [m

]

0

10

20

30

40

50

B

Elevation [m]0 20 40 60

Cou

nt

#105

0

2

4

6

8

10

12

14Elevations offset from 1161.76

Mean = 17.90Median = 15.02

Figure 1: The heat map represents the elevation of sand dunes on Mars, with two transects, A and B, drawn over two specificdunes. The elevation, along with the peaks, of those dunes are then graphed as A and B respectively below the heat map.The histogram is a count of how often certain elevations were measured and the mean and median of those measurements.

Acknowledgements. Thank you to Akshay Mehra and Christopher Harig for helping me detect problems in5

my code.6

Homework 3 — Data reduction i

0 10 20 30 40 50 60 70 80 90 100

−10

−8

−6

−4

−2

0

2

4

6

8

10

mynetidl05 − A 1.00 4.00 5.00 P 10.00 30.00 40.00 ph 0.00 1.57 0.00

time [s]

sign

als

(indi

vidu

al p

iece

s an

d th

eir

sum

)


0 10 20 30 40 50 60 70 80 90 100−10

−5

0

5

10

time [s]

sign

al a

nd it

s pr

edic

tion

rms prediction error is 2.78 data unitsvariance reduction 59.56%

0 5 10 15 20 25 30 35 40 450

1

2

3

4

5

period [s]

ampl

itude

[uni

ts o

f the

dat

a]

mynetidl05 − A 0.16 0.69 4.73 P 9.00 20.00 42.00


0 10 20 30 40 50 60 70 80 90 100−10

−5

0

5

10

time [s]

sign

al a

nd it

s pr

edic

tion


0 5 10 15 20 25 30 35 400

1

2

3

4

5

period [s]

ampl

itude

[uni

ts o

f the

dat

a]

mynetidl05 − A 1.00 4.00 5.00 P 10.00 30.00 40.00


0 10 20 30 40 50 60 70 80 90 100−10

−5

0

5

10

time [s]

sign

al a

nd it

s pr

edic

tion


0 5 10 15 20 25 30 35 40 45 500

1

2

3

4

period [s]

ampl

itude

[uni

ts o

f the

dat

a]

mynetidl05 − A 1.04 3.51 4.28 P 10.00 30.00 46.00


0 10 20 30 40 50 60 70 80 90 100−15

−10

−5

0

5

10

15

time [s]

sign

al a

nd it

s pr

edic

tion


0 5 10 15 20 25 30 35 40 450

1

2

3

4

5

period [s]

ampl

itude

[uni

ts o

f the

dat

a]

mynetidl05 − A 0.39 0.63 4.74 P 9.00 20.00 42.00


0 10 20 30 40 50 60 70 80 90 100−15

−10

−5

0

5

10

15

time [s]

sign

al a

nd it

s pr

edic

tion


0 5 10 15 20 25 30 35 400

1

2

3

4

5

period [s]

ampl

itude

[uni

ts o

f the

dat

a]

mynetidl05 − A 1.14 4.22 5.07 P 10.00 30.00 40.00


0 10 20 30 40 50 60 70 80 90 100−15

−10

−5

0

5

10

15

time [s]

sign

al a

nd it

s pr

edic

tion


0 5 10 15 20 25 30 35 40 45 500

1

2

3

4

period [s]

ampl

itude

[uni

ts o

f the

dat

a]

mynetidl05 − A 1.09 3.74 4.27 P 10.00 30.00 46.00


0 10 20 30 40 50 60 70 80 90 100−10

−5

0

5

10

time [s]

sign

al a

nd it

s pr

edic

tion


0 5 10 15 20 25 30 35 40 450

0.5

1

1.5

2

2.5

3

3.5

period [s]

ampl

itude

[uni

ts o

f the

dat

a]

mynetidl05 − A 0.14 0.55 3.55 P 9.00 20.00 42.00


0 10 20 30 40 50 60 70 80 90 100−10

−5

0

5

10

time [s]

sign

al a

nd it

s pr

edic

tion


0 5 10 15 20 25 30 35 400

1

2

3

4

period [s]

ampl

itude

[uni

ts o

f the

dat

a]

mynetidl05 − A 0.74 3.01 3.78 P 10.00 30.00 40.00


0 10 20 30 40 50 60 70 80 90 100−10

−5

0

5

10

time [s]

sign

al a

nd it

s pr

edic

tion


0 5 10 15 20 25 30 35 40 45 500

0.5

1

1.5

2

2.5

3

period [s]

ampl

itude

[uni

ts o

f the

dat

a]

mynetidl05 − A 0.83 2.68 3.13 P 10.00 30.00 46.00

Homework 4 — All of the above i

0 50 100 150 200 250

4.958

4.96

4.962

4.964

4.966

x 104

0 50 100 150 200 250

4.945

4.95

4.955

4.96

4.965

4.97x 10

4

time [s]

sign

al a

nd it

s pr

edic

tion


Hello Earth! › files › NAGT... · Homework 3 — Data analysisFRS 135, LAB 04 ilillianw, 1 of 1...

Documents

Transcript of Hello Earth! › files › NAGT... · Homework 3 — Data analysisFRS 135, LAB 04 ilillianw, 1 of 1...