2.0 Modules¶
Visualizing data using matplotlib¶
In the last lesson, you learned about lists and using indexing to access the data within them. Data can be strings of characters or it can be numerical. You can even create a list of lists!
In this lesson we will be learning about how to visualize data using a module called matplotlib. Modules in Python are sets of functionalities that allow you to complete complex tasks with ease. Most importantly, they are a group of functions that can allow you to achieve specific goals. One of the most popular and useful modules is matplotlib, which allows you to visualize data.
In the video below, you will learn how to load matplotlib and use its functions to plot an example dataset of averaged grapevine leaf shapes from 15 species in the genera Vitis and Ampelopsis. You can learn more about this data and the species from which it is derived in the following publication: Bryson, Brown, Mullins, Dong et al., Composite modeling of leaf shape along shoots discriminates Vitis species bettern than individual leaves, Applications in Plant Sciences, 8(12): e11404, by the students of the MSU NRT-IMPACTS class from Fall 2019. Figure 1 shows the diversity of leaf shapes among grapevine species measured, and Figure 2 shows landmarks, x and y coordinates found on every leaf that can be used to measure shape. The average values of superimposed landmarks were used to create the shapes that you will be visualizing today.
Today’s lesson is all about exploring and creativity: designing aesthetically pleasing plots! Some links below to websites allowing you to choose colors in matplotlib and a gallery of example plots to explore more:
A list of named colors in matplotlib
In the cell below are the data that we will be working with in this lesson that are used in the video. These are lists of x and y coordinate values for 15 different Vitis and Ampelopsis species. Execute the cell below, read over the learning objectives, and then follow along in the video tutorial to start making plots using matplotlib!
# This cell contains lists of x values and y values for
# leaf outlines of 15 Vitis and Ampelopsis species.
# Each list has the abbreviated first initial of the genus and species epithet
# Ampelopsis "acoutifolia" (actually aconitifolia)
# NOTE: There is a transcription error for this species, which is actually
# Ampelopsis aconitifolia (it is not A. "acoutifolia")
# The mistake is propagated in the videos, narration, text, and notebooks
# but it does not affect the lesson at hand for plotting in matplotlib
Aaco_x = [13.81197507,-14.58128237,-135.3576208,-3.48017966,-285.0289837,-4.874351136,-126.9904669,10.54932685,170.4482865,40.82555888,205.158889,124.6343366,13.81197507]
Aaco_y = [27.83951365,148.6870909,157.2273013,35.73510131,-30.02915903,9.54075375,-280.2095191,0.200400495,-234.1044141,20.41991159,41.33121759,96.75084391,27.83951365]
# Ampelopsis brevipedunculata
# NOTE: This species is now referred to as A. glandulosa var. brevipedunculata
Abre_x = [40.00325135,-81.37047548,-186.835592,-139.3272085,-287.5337006,-89.61277053,-134.9263008,47.43458846,144.6301719,163.5438321,225.9684307,204.719859,40.00325135]
Abre_y = [96.8926433,203.3273536,134.0172438,99.7070006,-81.35389923,-17.90701212,-335.624547,-80.02986776,-262.0385648,-27.31979918,-42.24377429,82.08218538,96.8926433]
# Ampelopsis cordata
Acor_x = [41.26484889,-99.68651819,-203.5550411,-181.4080156,-226.4063517,-174.1104713,-142.2197176,81.25359041,113.9079805,205.9930561,230.8000389,226.6914467,41.26484889]
Acor_y = [105.1580727,209.8514829,131.8410788,111.9833751,-70.79184424,-60.25829908,-326.5994491,-170.6003249,-223.0042176,-44.58524791,-45.80679706,71.64004113,105.1580727]
# Vitis acerifolia
Vace_x = [47.55748802,-102.1666218,-218.3415108,-183.5085694,-234.8755094,-152.1581487,-113.8943819,53.48770667,84.83899263,206.557697,240.589609,243.5717264,47.55748802]
Vace_y = [111.9982016,241.5287104,125.6905949,110.350904,-108.1932176,-74.67866027,-283.2678229,-161.1592736,-243.1116283,-54.52616737,-68.953011,95.74558526,111.9982016]
# Vitis aestivalis
Vaes_x = [34.13897003,-59.06591289,-192.0336456,-169.5476603,-261.8813454,-154.4511279,-132.6031657,56.04516606,119.9789735,205.0834004,246.928663,209.2801298,34.13897003]
Vaes_y = [80.26320349,227.2107718,155.0919347,123.2629647,-86.47992069,-70.12024178,-317.80585,-156.8388147,-247.9415158,-31.73423173,-28.37195726,120.2692722,80.26320349]
# Vitis amurensis
Vamu_x = [36.94310365,-63.29959989,-190.35653,-180.9243738,-255.6224889,-172.8141253,-123.8350652,60.05314983,113.598307,218.8144919,238.6851057,210.9383524,36.94310365]
Vamu_y = [87.06305005,230.9299013,148.431809,128.4087423,-88.67075769,-84.47396366,-298.5959647,-181.4317592,-241.2343437,-37.53203788,-30.63962885,115.7064075,87.06305005]
# Vitis cinerea
Vcin_x = [41.13786595,-78.14668163,-195.0747469,-185.81005,-238.1427795,-181.5728492,-127.6203541,65.24059352,103.8414516,214.1320626,233.1457326,222.7549456,41.13786595]
Vcin_y = [98.40296936,233.6652514,136.6641628,117.9719613,-86.41814245,-86.14771041,-310.2979998,-190.9232443,-230.5027809,-50.27050419,-42.94757891,107.8271097,98.40296936]
# Vitis coignetiae
Vcoi_x = [36.29348151,-51.46279315,-183.6256382,-176.7604659,-253.3454527,-191.8067468,-123.413666,66.11061054,111.4950714,215.7579824,236.7136632,197.5512918,36.29348151]
Vcoi_y = [86.42303732,222.7808161,150.0993737,127.4697835,-85.23634837,-93.3122815,-301.819185,-203.7840759,-239.8063423,-35.30522815,-25.15349577,121.1295308,86.42303732]
# Vitis labrusca
Vlab_x = [33.83997254,-63.35703212,-191.4861127,-184.3259869,-257.3706479,-179.056825,-124.0669143,68.23202857,123.213115,222.8908464,243.056641,205.2845683,33.83997254]
Vlab_y = [81.34077013,222.8158575,153.7885633,132.4995037,-80.2253417,-80.67586345,-296.8245229,-185.0516494,-238.8655248,-38.2316427,-29.21879919,111.424232,81.34077013]
# Vitis palmata
Vpal_x = [31.97986731,-68.77672824,-189.26295,-164.4563595,-260.2149738,-149.3150935,-131.5419837,65.86738801,127.3624336,202.6655429,240.0477009,219.0385121,31.97986731]
Vpal_y = [78.75737572,232.9714762,149.7873103,124.8439354,-71.09770423,-56.52814058,-329.0863141,-149.308084,-231.1263997,-33.22358667,-33.0517181,114.3110289,78.75737572]
# Vitis piasezkii
Vpia_x = [18.70342336,-28.68239983,-133.7834969,-32.76128224,-305.3467215,-7.429223951,-146.2207875,21.81934547,163.1265031,65.21695943,203.4902238,139.6214571,18.70342336]
Vpia_y = [41.05946323,160.3488167,157.9775135,64.93177072,-59.68750782,18.85909594,-362.1788431,7.556816875,-253.8796355,21.33965973,17.69878265,93.72614181,41.05946323]
# Vitis riparia
Vrip_x = [44.65674776,-85.47236587,-205.1031097,-174.088415,-239.9704675,-161.1277029,-125.4900046,58.08609552,89.2307808,204.9127104,236.0709257,229.8098573,44.65674776]
Vrip_y = [106.5948187,235.8791214,130.341464,116.8318515,-110.5506636,-76.73562488,-300.1092173,-169.0146383,-247.0956802,-42.2253331,-54.23469169,103.9732427,106.5948187]
# Vitis rupestris
Vrup_x = [51.29642881,-132.9650549,-227.6059714,-201.31783,-207.965755,-149.2265432,-98.64097334,48.33648281,75.91437502,208.7784453,237.4842778,263.3479415,51.29642881]
Vrup_y = [123.7557878,233.5830974,109.6847731,95.43848563,-95.82512925,-80.06286127,-236.7411071,-163.7331427,-213.2925544,-77.04510916,-86.40789274,69.86940263,123.7557878]
# Vitis thunbergii
Vthu_x = [22.61260382,-3.204532702,-150.3627277,-79.39836351,-271.8885204,-70.74704134,-168.6002498,36.68300146,172.978549,116.9174032,227.8346055,148.3453958,22.61260382]
Vthu_y = [50.82336098,194.3865012,181.2536906,86.8671412,-57.33457233,-23.85610668,-334.279317,-67.36542042,-234.1205595,7.151772223,28.16801823,138.9705667,50.82336098]
# Vitis vulpina
Vvul_x = [39.44771371,-83.62933643,-194.2000993,-175.9638941,-227.8323987,-180.8587446,-135.986247,71.94543538,99.8983207,207.0950158,231.7808734,222.7645396,39.44771371]
Vvul_y = [96.44934373,230.0148139,136.3702366,119.8017341,-83.09830126,-75.38247957,-332.9188424,-184.4324688,-222.8532423,-41.89574792,-44.70218529,101.9138055,96.44934373]
# Average grape leaf
avg_x = [35.60510804,-67.88314703,-186.9749654,-149.5049396,-254.2293735,-135.3520852,-130.4632741,54.4100207,120.7064692,180.696724,232.2550642,204.8782463,35.60510804]
avg_y = [84.95317026,215.7238025,143.85314,106.742536,-80.06000256,-57.00477464,-309.8290405,-137.6340316,-237.7960327,-31.10365842,-30.0828468,103.1501279,84.95317026]
🐍 Python learning objectives¶
Lists can store numerical data that can be plotted (1:12)
How to load in modules, sets of functionalities that allow us to do tasks in Python (2:37)
How to create plots, scatter plots, filled polygons (4:21)
How to manipulate shape, size, and color in plots (8:20)
How to plot data on top of each other and use a legend (17:10)
How to create subplots (19:16)
🌻 Plant learning objectives¶
Phenotype is what a plant is
Phenotype can be measured
Genetic differences between closely related species results in variation
Morphology is one aspect of phenotype that can be measured using geometry
How to load in modules, sets of functionalities that allow us to do tasks in Python¶
Watch this video from 0:00 to 4:09
# To load the video, execute this cell by pressing shift + enter
from IPython.display import YouTubeVideo
from datetime import timedelta
start=int(timedelta(hours=0, minutes=0, seconds=0).total_seconds())
end=int(timedelta(hours=0, minutes=4, seconds=9).total_seconds())
YouTubeVideo("PJ1dvAgOAj0",start=start,end=end,width=640,height=360)
The following is a transcript of the video.
Before we plot anything, we have to learn how to load in modules. Modules are sets of functionalities that allow us to do common tasks in Python.
The module that most people use to plot is matplotlib and it’s used quite often. The way we load in matplotlib is that we use import. So we type out import and then we type matplotlib. We also type dot pyplot (“.pyplot”) because this is a sub module that we’ll be using for plotting. When you use the functions in a module you have to refer to them by name. So you’ll say “something module dot function”. It would be a lot to write “matplotlib” or “pyplot” every single time you use a function so we import matplotlib as plt, because as you’ll see, all we have to do is write plt dot function, which makes things very simple.
For matplotlib, specifically, there’s a second line of code. It’s percentage (“%”) matplotlib space inline and this allows us to display plots inline. matplotlib is so commonly used that a lot of people will execute these two lines of code to import matplotlib everytime they use a Jupyter notebook, because it is used that often. You can just copy and paste these lines of code every time you use a Jupyter notebook and matplotlib will be there for you to use.
# import will load in the module
# pyplot is the submodule of matplotlib that we will be using
# 'as plt' refers to how we will refer to the module to use it
# for example, plt.plot()
# %matplotlib inline
# You will almost always use matplotlib
# You can copy and paste this code into every notebook!
import matplotlib.pyplot as plt
%matplotlib inline