Projected coordinates are not being unprojected back to the same coordinates
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- Dominant language
- TypeScript
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Description
`unproject()` seems to be returning the incorrect coordinates when point is off screen. This issue becomes more apparent on higher zoom levels. The objective is to draw multiple lines between two points using only two sets of coordinates.
In the example below, I've removed all calculations I was performing on each zoom event and only projecting then unprojecting the same coordinates.
**mapbox-gl-js version**: version: v2.6.0
**browser**: Tested on Chrome, Safari, Firefox
### Steps to Trigger Behavior
1. Draw a line between using two sets of coordinates by adding a source with a line layer
2. On zoom event, project the each coordinate then unproject each coordinate and update source with resulting coordinates.
### Expected Behavior
**Zoomed out**
**Zoomed in at level 16**
### Actual Behavior
**Zoomed in at level 16**
**I manually added the line at zoom 16 then zoomed out to see the resulting line:**
Contributor guide
First steps
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Research direction
The issue names no source file or test; start by reproducing the project/unproject round trip during zoom events at a high zoom level, using the described two-coordinate line example. Trace the map.project() and map.unproject() entry points and verify that off-screen coordinates remain unchanged after the round trip.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- typescript
- Domain
- frontend, web-dev
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100