Astro 3310 Fall 2015
LAB #5
-----Please copy this document to the REPORT sub-directory from the
expanded LAB5_Data_Package_FA15.tar.gz. Then, edit it to write your
answers in all the "______" areas. When finished, create a tar.gz
archive of the REPORT directory and all of its contents, then scp
the file to datafarm.astro.cornell.edu and place it in:
/data/Courses/A3310/FA15/”your netid”/LAB5/
Remember that you will only get credit for the files that you put in
the REPORT sub-directory and copy to datafarm. Please make sure
that you keep a Matlab workbook with all of the commands you used to
answer the questions in the lab. Feel free to comment and organize
your workbook so that it will be easy for us to follow your
algorithms when we execute the doe. If you generate any functions
for the lab, ensure that they are also in the REPORT sub-directory
and properly called from the workbook file. For you convenience,
there is a template for the workbook file already in the REPORT subdirectory.
YOUR NAME: _______________________________
Your NetID: __________
Problem 1:Playing with ArcGIS and Titan (and a little Matlab)
1. Load the Synthetic Aperture Radar (SAR) mosaic of Titan’s north
polar terrain(SAR_POLA_MOSAIC_S0C_180W180E_55N90N_256PPD_v11.cub)
into a new ArcGIS project and stretch it so that you can clearly
see the borders of the three large seas (Kraken Mare, Ligeia
Mare, and Punga Mare). Switch your project to “layout view” and
export an image centered around the three seas. Place a copy of
that image below.
Hint: Make use of the tutorials listed in the Course Website and
included in the BACKGROUND sub-directory of the lab data package.
Answer:
Insert your figure of the three seas below.
2. Create a shapefile using ArcCatalog and map the borders of all
three seas. Export an image centered around the three seas with
your shapefiles overlying the image. Place a copy of the image
below.
Hint: Make use of the tutorials listed in the Course Website and
included in the BACKGROUND sub-directory of the lab data package.
Answer:
Insert your figure of the three seas below.
3. Load your sea shapefile into Matlab using the shaperead function
and then use the areaint function to determine the area of each
sea.
Hint: Be sure to properly define the ellipsoid when calculating
the area (Titan’s ellipsoid parameter is [2575,0] in kilometers)
Answers:
Area of Kraken Mare = ______________ km2
Area of Ligeia Mare = ______________ km2
Area of Punga Mare = ______________ km2
4. Load the Synthetic Aperture Radar (SAR) mosaic of Titan’s south
polar terrain(SAR_POLA_MOSAIC_S0C_180W180E_90S55S_256PPD_v10.cub)
into a new ArcGIS project and stretch it so that you can clearly
see the borders of the three four paleo-Mare basins and Ontario
Lacus. Switch your project to “layout view” and export an image
centered around the paleo basins. Place a copy of that image
below.
Hint: Make use of the tutorials listed in the Course Website and
included in the BACKGROUND sub-directory of the lab data package.
Answer:
Insert your figure of the south polar terrain below.
5. Create a shapefile using ArcCatalog and map the borders of the
four paleo basins. Export an image centered around the basins
with your shapefiles overlying the image. Place a copy of the
image below.
Hint: Make use of the tutorials listed in the Course Website and
included in the BACKGROUND sub-directory of the lab data package.
Answer:
Insert your figure of the three seas below.
6. Load your paleo-mare basin shapefile into Matlab using the
shaperead function and then use the areaint function to determine
the area of each sea. How do the areas of the paleo basins
compare to the areas of the northern seas?
Hint: Be sure to properly define the ellipsoid when calculating
the area (Titan’s ellipsoid parameter is [2575,0] in kilometers)
Answers:
Area
Area
Area
Area
of
of
of
of
Basin
Basin
Basin
Basin
1
2
3
4
=
=
=
=
______________
______________
______________
______________
km2
km2
km2
km2
Problem 2: Playing with Shapefiles in Matlab
1. Using the shaperead function, load earth_lakes.shp into Matlab.
Step through each of the structure elements (i.e., lake
shapefiles) and populate a vector of the lake areas.
Hint: Some of the shapefiles are complex, so you can sum the
output of areaint in the event that a single lake shapefile
returns multiple area results:
area_val = sum(areaint(lat,lon,[2575,0]));
where lat is shp(i).Y and lon is shp(i).X (shp is the variable
name used when the shapefile was read into matlab and i is the
loop position). Make a histogram of the area values and insert it
below.
Answer: Insert your histogram figure below.
2. Using the shaperead function, load mars_lakes.shp into Matlab.
Step through each of the structure elements (i.e., lake
shapefiles) and populate a vector of the lake areas.
Hint: Some of the shapefiles are complex, so you can sum the
output of areaint in the event that a single lake shapefile
returns multiple area results:
area_val = sum(areaint(lat,lon,[2575,0]));
where lat is shp(i).Y and lon is shp(i).X (shp is the variable
name used when the shapefile was read into matlab and i is the
loop position). Make a histogram of the area values and insert it
below.
Answer: Insert your histogram figure below.
3. Using the shaperead function, load titan_lakes.shp into Matlab.
Step through each of the structure elements (i.e., lake
shapefiles) and populate a vector of the lake areas. Add the
three areas your calculated for Titan’s seas to the vector of
Titan lake areas.
Hint: Some of the shapefiles are complex, so you can sum the
output of areaint in the event that a single lake shapefile
returns multiple area results:
area_val = sum(areaint(lat,lon,[2575,0]));
where lat is shp(i).Y and lon is shp(i).X (shp is the variable
name used when the shapefile was read into matlab and i is the
loop position). Make a histogram of the area values and insert it
below.
Answer: Insert your histogram figure below.
4. Now, generate a cumulate distribution for each of your lake areas
vectors. First, generate the area bins (x axis) for your
cumulative distribution using the following line of code:
x = logspace(log10(100),log10(1e5),100); km^2
Now, for each of your area vectors, determine the cumulative
number of lakes that are have an area of x(i) or larger. In other
words:
Y_earth(i) = numel( area_earth( area_earth > x(i) );
After generating the cumulative distributions for lakes on Earth,
Mars, and Titan, plot them alongside each other and export a copy
of your plot to place below.
Do you notice anything interesting about the plots? What are the
differences? Can you think of what those difference may mean in
terms of lake formation or destruction (via erosion)?
Answer:
Put your cumulative distribution plot below.