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CSE 163

Geopandas�

Suh Young Choi

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Announcements

THA 4 Peer Reviews due tonight

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Checkpoint 4 (Stats, ML, and Maps) open now; due next Monday

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Project/Portfolio Part 2 due tomorrow

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THA 5: Mapping due next Thursday

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No resubmissions on the Creative Component (unless… 👀)

  • Possibility of a Bonus Resubmission Period from 3/11 – 3/13
  • Submit any ONE Technical Component and any ONE Creative Component
  • Doesn’t have to be for the same THA!
  • Course eval goes out on March 2; 65% response rate by 3/9 and everyone gets a bonus resub!

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This Time

  • Geospatial data
  • Using Geopandas

Last Time

  • Machine Learning
  • Model Evaluation

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Geospatial Data

  • Simply put, maps!
  • Represents places in the world and accompanying data

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Shapes

  • These live in the geometry column
  • Lines and/or points that indicate shapes
  • Some examples are given here:

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zip

  • zip is a helpful built-in function to help you combine lists

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  • Note: zip does not return a list! It returns a generator
    • Can only access the values by iterating over them
    • Can only be used once! Iterating “consumes” the series

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x = [1,2,3]

y = [4,5,6]

zip(x, y)

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Geopandas

  • Exactly like pandas, but with some extra features for geo data
  • Types
    • GeoDataFrame
    • GeoSeries

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import geopandas as gpd

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df = gpd.read_file('data_file.shp')

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df.plot(column='some_col', legend=True)

plt.savefig('plot.png')

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Matplotlib

  • Before, we were using a lot of matplotlib stuff blindly
  • Default plots gets plotted on a global figure (think canvas)
    • Multiple plots would overwrite each other
  • You have to do extra work to get more information on the same set of axes.

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fig, ax = plt.subplots(1)

<plot1>(ax=ax)

<plot2>(ax=ax)

fig.savefig('plot_together.png')

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Matplotlib

  • Before, we were using a lot of matplotlib stuff blindly
  • Default plots gets plotted on a global figure (like a canvas)
    • Multiple plots would overwrite each other
  • You have to do extra work to get more information on the same set of axes.

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fig, ax = plt.subplots()

<plot1>(ax=ax)

<plot2>(ax=ax)

fig.savefig('plot_together.png')

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fig, [ax1, ax2] = plt.subplots(1, 2) # width, height

<plot1>(ax=ax1)

<plot2>(ax=ax2)

fig.savefig('plot_separate.png')

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Matplotlib

  • Before, we were using a lot of matplotlib stuff blindly
  • Default plots gets plotted on a global figure (like a canvas)
    • Multiple plots would overwrite each other
  • You have to do extra work to get more information on the same set of axes.

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fig

ax1

ax2

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Matplotlib

  • Before, we were using a lot of matplotlib stuff blindly
  • Default plots gets plotted on a global figure (like a canvas)
    • Multiple plots would overwrite each other
  • You have to do extra work to get more information on the same set of axes.

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fig

ax1

ax2

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Matplotlib

  • Before, we were using a lot of matplotlib stuff blindly
  • Default plots gets plotted on a global figure (like a canvas)
    • Multiple plots would overwrite each other
  • You have to do extra work to get more information on the same set of axes.

​

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fig

ax1

ax2

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Hurricane Florence

Demo

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Hurricane Florence

Demo

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Before Next Time

● Complete Lesson 17

○ Remember not for points, but do go towards Weekly Tokens

● THA 4 Peer Reviews due tonight

● Complete Project/Portfolio Part 2!

● Go to section tomorrow!!

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Next Time

  • Two special Geopandas functions

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