Analysis

I was given two activities with subparts I was supposed to complete for analysis of data collected from 2019-2021.

Time Series Analysis

My task was to examine the data and see if there are differences in Phycocyanin (PC), Chlorophyll-a (Chla), and PC/Chla over time.

  • I examined the variability in PC, Chla, and PC/Chla over the course of the individual summers, as well as between each year.

  • I also examined the comparable data sampled to the continuous data collection buoy on Lake Mendota.

Spatial Analysis

My task was to examine the data to see if there were spatial differences in Phycocyanin (PC), Chlorogphyll-a (Chla), and PC/Chla in the different grid boxes used for sampling (Grids 1 --> 35).

  • I examined the differences between littoral and pelagic zones.

  • I also examined if there were variable difference between two different sides of the lake (the inlet and outlet).

Matlab

To do the analysis of hundreds of lines of collected data, I learned the programming system Matlab.

Here are some of the commands I took note of:

General Commands

  • pwd - present working directory

  • ls - opens programs (list of what is in the working directory)

  • % - comments

  • ; - used after command to make it silent

  • x[ ] - used fro vectors (#s only) row vector

  • y=x' - makes vector column

  • mat= - matrix(ex: [123; 732; -123])

  • ones - gives you ones in the matrix ones

  • zeros - gives you zeros in the matrix zero

  • NaN - missing data (Not a Number)

  • ' ' - empty char array

  • f=[d d] - concatenation

  • array - pure # array (ex: a=[1 2 3])

  • data structure - cell array (ex: a{ 1 'C' 'letus' [1 2]})

  • help ____ - if you write the command after, it will tell you what the command is

  • eval ( ) - evaluated if there are numbers

  • clf - clears figure (ex: figure(1): clf)

  • ~ - NaN

  • strcmp - compares string data

  • {: , 4} - shows everything on data column 4

  • cd - change directory

  • control p - previous command (keeping hitting control p to keep going through previous commands) (if you write something ' ' then control p it finds the previous command that has the same first letters or word)

  • control c - stops the program

  • & - and

  • | - or

Mathematical Commands

  • * - multiplication

  • mat. * mat2 - element wise multiplication

  • mat * mat2 - normal matrix multiplication

  • sin(x) - sin of x

  • x.^2 - squaring

  • sqrt(#) - square root

  • std - standard deviation

  • mean - mean value


Side Notes

  • indent 3 spaces for readability and logic

Graphing Commands

Naming:

  • title('something...') - for titling figures

  • xlabel(' ') - x axis title

  • ylabel(' ') - y axis title

  • zlabel(' ') - z axis title

Commands for Altercation:

  • grid on - turns the grid on in a figure

  • get(gca) - gets current axis

  • get(phandle(l) - shows all properties of line(l)

  • set(gca) - shows all the commands you can do within your graphs

Markers:

  • ':' - solid line

  • '-' - solid line

  • '--' - dash line

  • '-.' dash dotted line

  • 'o' - O

  • '+' - +

  • '*' - *

  • '.' - .

  • '-' - -

  • 'l' - i

  • 's' - square shape

  • 'd' - diamond shape

  • '^' - triangle (point facing upwards)

  • '>' - triangle (point facing right)

  • '<' - triangle (point facing left)

  • 'p' - star shape

  • 'h' - hexagram shape

  • 'x' - x

Example of the Analyzed Data

Time Versus Chlorophyll-a

There are 35 different lines representing the 35 different grids. The lines show the change of Chlorophyll-a present within Lake Mendota during the summer of 2021.

Average of Chla by Year (2019-2021)

Here is the average of Chlorophyll-a within grids 1-35 over the years (2019-2021)

Chlorophyll-a versus Distance from Yahara River inlet

This graph shows the average of the grids on the same row going from the inlet (Yahara River) to the outlet.