ENV 617 Assignment 6
Spring 2023
Introduction:
In this assignment, we’ll make a map of water basins in the African continent. We’ll map the
change in the mean annual air temperature of each water basin, and include major lakes on the
map for reference.
The learning objectives of this assignment are to:
– Practice creating your own Colab
– Practice reading in spatial data
– Practice combining related (spatial) datasets
– Practice fine tuning maps.
We haven’t provided you a Colab template for this assignment. Instead, you will create your own
Colab (go to https://colab.research.google.com/ and click “New Notebook”) and commit it back
to your assignment 5 repository. (You may need to login and authenticate GitHub.) Make sure
your colab is organized, runs top to bottom, and is easy to follow. Detailed instructions are
below:
Goal:
Your goal is to replicate the map at the bottom of this document as closely as possible using the
datasets below. (Don’t worry if your colors, scales, or aspect ratios are slightly different.)
Data:
Use the three data sources below to create your map:
1. HydroLAKES
○ Summary: Developed by the WWF, HydroLAKES is a database providing the
shoreline polygons of all global lakes with a surface area of at least 10 ha. We’ll
be using the global dataset. Read more here.
○ Documentation:
https://www.hydrosheds.org/images/inpages/HydroLAKES_TechDoc_v10.pdf
○ Data link: Download zip file of shapefiles here:
https://97dc600d3ccc765f840c-d5a4231de41cd7a15e06ac00b0bcc552.
ssl.cf5.rackcdn.com/HydroLAKES_polys_v10_shp.zip
○ Citation:
Messager, M.L., Lehner, B., Grill, G., Nedeva, I., Schmitt, O. (2016): Estimating
the volume and age of water stored in global lakes using a geo-statistical
approach. Nature Communications: 13603. doi: 10.1038/ncomms13603. Data is
available at www.hydrosheds.org
ENV 617 Assignment 6
Spring 2023
2. HydroBASINS
○ Summary: Developed by the WWF, HydroBASINS is a series of polygons that
depict watershed boundaries and sub-basin delineations globally. We’ll be using
the dataset of Africa only. Boundaries are given for 12 different levels of
geographic granularity: Level 1 is all of Africa, and level 12 is…a very small area.
Read more here
○ Documentation:
https://www.hydrosheds.org/images/inpages/HydroBASINS_TechDoc_v1c.pdf
○ Data link: Download zip file of shapefiles here:
https://www.dropbox.com/sh/hmpwobbz9qixxpe/AACiujdXJ5DfsaK7zcK
OJyZpa/HydroBASINS/customized/af/hybas_lake_af_lev01-12_v1c.zi
p?dl=0
○ Citation:
Lehner, B., Grill G. (2013): Global river hydrography and network routing:
baseline data and new approaches to study the world’s large river systems.
Hydrological Processes, 27(15): 2171–2186. Data is available at
www.hydrosheds.org.
3. Water Basin Mean Annual Temperature
○ Summary: This is a dataset for scientific use that includes annual attribute data
for global lake and water basins between 1995 and 2015.
■ We will be using the data on mean annual air temperature (K) by water
basin by year.
■ The water basin identifiers are the same as those in HydroBASIN.
■ The basins included in this data span many basin levels (1-12) and do
overlap. (If you’re interested, the basins selected form a 1:1 mapping to
the HydroLAKES data)
■ This is an enormous dataset (>5 GB) so we’ve filtered the relevant
information for you and loaded it into our GitHub repository. We’ve only
included data for the African continent for 2000 and 2014.
○ Documentation: (Paper)
https://www.nature.com/articles/s41597-020-0517-4#Sec15
○ Data link: CSV on GitHub here:
https://raw.githubusercontent.com/envirodatascience/ENVS-6
17-Class-Data/main/basin_temp_africa_2000_2014.csv
○ Citation:
Labou, S.G., M.F. Meyer, M.R. Brousil, A.N. Cramer, and B.T. Luff. 2020. Global
lake area, climate, and population dataset ver 4. Environmental Data Initiative.
https://doi.org/10.6073/pasta/834e2d4e8ee7eb2fa9a5a5b32d759683 (Accessed
2021-10-06).
ENV 617 Assignment 6
Spring 2023
Suggested Steps:
● Read in Data:
a. Read in the HydroLAKES dataset into a geodataframe. (This may take a few
minutes, it’s really big)
b. Read in HydroBASIN data. You will see .shp shapefiles for basin levels 1-12 in
Africa. Read in the files for levels 1-9 into separate geodataframes. Use
.append() to combine the 9 different geodataframes into a single
geodataframes. Important: Make sure you append such that the basin levels are
in order: the level 1 geometry should be at the top of the geodataframe and the
level 9 geometry is at the bottom. This will ensure that the bigger polygons don’t
cover the smaller ones when plotted.
c. Read in the Water Basin Mean Annual Temperature data into a dataframe
● Calculate the change in mean annual temperature between 2000 and 2014
a. Pivot the Water Basin Mean Annual Temperature data wide. Calculate the
change in average annual temperature between 2000 and 2014 in a new column.
Be thoughtful about your units.
● Merge water basin temperature data onto water basin geometries
a. Join the Water Basin Mean Annual Temperature data with the HydroBASINS
data. Not every basin in the HydroBASINS data will have temperature data. Just
include the records that exist in both datasets.
● Check CRS
a. If you haven’t already, check the CRS of your two geodataframes. To plot, you
will want to be in them to use the same CRS
● Create Plot
a. Replicate the map below as best as you can (don’t worry about the exact coloring
or aspect ratio). The .png for this map is in your repo if you’d like a closer look.
b. Think about the order of the layers
c. Make your figure size big enough to see things. This is high resolution data – it
won’t get grainy.
ENV 617 Assignment 6
Spring 2023
Target Map: