feat: generate h3 polygons and create webmap

[ioalexei]

Addresses issue #25

Adds files:

• points_to_h3.py
• create_webmap.py
• templates/maplibre_template.html

Points to H3

Input:

• Input file: point layer with GVI scores
• Output file
• (Optional) H3 cell resolution (see here)

Output:

• File containing h3 polygons at the specified resolution with mean GVI score as an attribute

Example usage:

• python3 -m src.points_to_h3 data/processed/gvi_score_layer.gpkg data/processed/h3_polygons.gpkg 11

Create webmap

Input:

• Input file: H3 polygon file
• Output: HTML file to display MapLibre webmap
• (Optional) filename for HTML file
• (Optional) default zoom level for webmap

Output:

• HTML file that contains javascript to generate a webmap showing the H3 polygons, styled by mean GVI score

Example usage:

• python3 -m src.create_webmap ./data/processed/h3_polygons.gpkg ./outputs gvi_webmap.html 10

[danbjoseph]

• When I generate the web map and then open the file in a browser the map is blank and there is an error is in the console. is it possible to have it generate the overlay but just not show the basemap if there's no API key? can you add details to the Readme about the API key (where to get it, where to put it)?
  

• hex grids look good, although trying to generate with resolution 9 results in an error

[ioalexei]

Added a note to the ReadMe re. MapTiler API key - will look into the other comments and come back to you

[danbjoseph]

also, i added a MapTiler API key to the .env file but it doesn't seem to be reading it in.

[ioalexei]

2e3586c fixes the Maptiler API issue by adding load_dotenv() to the create_webmap script and correcting an error in the HTML template

the error above is because the function expects zoom level to be the 4th of 4 arguments (input data, output folder, output filename, zoom level) - because only 3 were passed, it interpreted zoom level as the file name. I've made a mistake in the example in the documentation.

Is it better to not ask for a separate folder and filename and just take a path to a file for the output? Or should I just update the readme to give a code sampe that will work with this pattern

[danbjoseph]

yeah, i think a path to the file (instead of separate path and filename) matches the other steps?

[ioalexei]

Updated with ioalexei@b42316d

[danbjoseph]

this is looking good, except for it to render the hex layer when there isn't a MapTiler API key, it seems that the .env file has to have...

MAPTILER_API_KEY = "None"

if the user copies the template and doesn't touch the line then it will be MAPTILER_API_KEY = "MY_MAPTILER_API_KEY" and it doesn't work? or if they delete the line and the MAPTILER_API_KEY key isn't present, it doesn't work?

[danbjoseph]

if there is no MAPTILER_API_KEY line it works (shows the hex grid without a base map)

MAPTILER_API_KEY = "MAPTILER_API_KEY"  # doesn't work 
MAPTILER_API_KEY = ""  # doesn't work 

i guess we could just put a commented note in the .env.example file to remove the line if not used?

[ioalexei]

Added a new commit to account for a blank variable - but think it makes sense to put a note in the example .env file too as it might be hard to account of all the ways it could be invalid

[danbjoseph]

• functionality seems good to me for a merge
• as @ioalexei notes, ruff flags h3pandas as unused but it's used in line 79 of the hex creation file ( gdf.h3.geo_to_h3()) - is there an edit that will let the check pass?

[danbjoseph]

i don't thinkviridis is ideal for this because of the green for the mid values and then yellow and purple on the extremes. i added a commit to change it Greens.

[ioalexei]

Added fix for #88 :

• changed int to float for legend generation, so that it handles smaller ranges
• changed rounding in the legend labels to 2 decimal places rather than 0