matplotlib / matplotlib/basemap
Polygons and tissot across the edge in Mollweide:
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- Dominant language
- Python
- Stars
- 817
- Forks
- 395
- PR merge metrics
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Description
There seems to be a known problem with `tissot` and `Polygon` in the 'Mollweide' projection with basemap when these objects cross the 'limb' (180 degree line if the central longitude is 0. which is both the East and West edges of the map). The obvious solution is of course to split this into two polygons split at the limb. I realized that this was actually already available in examples (for tissots):
https://github.com/matplotlib/basemap/blob/master/examples/allskymap.py
and am wondering if there are plans to eventually replace `Basemap.tissot` or if there are deeper problems with this.
Contributor guide
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with Basemap.tissot and Polygon handling for the Mollweide projection, then compare the existing tissot-related approach in examples/allskymap.py. Reproduce the case where an object crosses the limb and determine the expected behavior; the issue does not define a concrete acceptance condition beyond addressing the edge-crossing problem.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- data-visualization
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100