Figure.choropleth: Plot a choropleth map.

[seisman]

This issue serves as the central place for discussing and tracking the implementation of the choropleth method in PyGMT, which is a thin wrapper for plot. The issue will be closed when the initial implementation is complete. Progress is tracked at PyGMT: Wrapping GMT modules.

Documentation

• GMT: https://docs.generic-mapping-tools.org/dev/plot.html
• GMT.jl: https://www.generic-mapping-tools.org/GMTjl_doc/documentation/modules/plot
• PyGMT: https://www.pygmt.org/dev/api/generated/pygmt.Figure.choropleth.html

GMT Option Flags and Modifiers

☑️: Implemented; ⬜: To be implemented/discussed; Strikethrough: Won't implement.

• data
• -A: straight line. Doesn't work here.
• -B: frame
• -C: cmap
• -D: Offsetting lines/symbols. Makes no sense
• -E: Error bar. Makes no sense.
• -F: Connecting points. Makes no sense
• -G: Used internally as -G+z
• -H: Scale symbol sizes. Makes no sense.
• -I: intensity
• -J: projection
• -L: Always set to True.
• -M: Implemented as Figure.fill_between
• -N: no_clip
• -S: For plotting symboles. Makes no sense.
• -R: region
• -U: Use Figure.timestamp instead.
• -V: verbose
• -W: pen
• -X/-Y: Use Figure.shift_origin
• -Z: Likely makes no sense
• -a: Implemented as the column parameter to specify the column name used for filling
• -b
• -c: panel
• -d
• -e
• -f
• -g
• -h
• -i
• -l
• -p: perspective
• -q
• -t: transparency
• -w
• -:
• --PAR=<value>: Use pygmt.Figure.

Notes on Input Formats

• Accepts geo-like objects implementing __geo_interface__ (e.g., GeoDataFrame) or OGR_GMT files.
• Uses aspatial to map the column to Z for fill.

Linked Pull Requests

• Initial feature implementation Add Figure.choropleth to plot choropleth maps #2798
• Add a tutorial or gallery example #choropleth

Related Issues and Discussions

• Add links to related wrapper discussions, API design threads, or upstream GMT changes here.