Session 5 [GIS] Feedback

@ramarty Thanks a lot, the materials look very good and enough for the session time. Here are my comments:

high level comments:

if you're not too busy in the next two weeks, consider moving the first part about concepts to slides. I think they will be better understood that way, similar to the API session. But it's okay to leave them there otherwise
add an overview of the contents in the README as the other sessions have
have you thought of your approach for exercises? for this session I'd suggest solving them along with participants but feel free to do what you think will be best

Convex hull: can you include a graphical example? it took me some time to understand what it meant from the concept description. Same for centroid, I think some participants will be new to it
I ran the code on Colab and the optional package installation was actually required. Otherwise the code doesn't run
When the WB Databricks is available, you should try downloading the data there to see that the firewall doesn't block it. If it does, let me know and I'll ask OIS to enable the access. If it can't be done on time, we'll have to ask all participants not to use databricks for this sessions, only colab
path for downloading from GADM and OSM: data folder should be created. Add this in instructions or modify path so that folder creation is not required (preferred, I think). Also, add code comments to explain what each line does in the GADM download and in next blocks
nga2_gdf.explore() produced an error on Colab because package "mapclassify" is not installed. It should be in the required packages
if possible, don't leave spaces between bang and bash commands, the other sessions don't have spaces and participants will ask why
add a line saying what each package loaded/downloaded does, something like: !pip install pandas # <-- for tabular data operations
when running the block to download school data for Lagos there are two warnings, including one from deprecation. This is okay, but remember to say it will show up so participants don't panic