[Pessimistress]

For #10739

Background

Major conceptual clean up of projection pipeline. Now explicitly separates:

• Layer's data coordinate system
• Layer's packed positions attribute coordinate system
• View's target CRS coordinate system
• Shaderlib's common space

For example, MVTLayer in v9.4 creates sublayers with coordinateSystem: 'cartesian' in MapView and coordinateSystem: 'lnglat' in GlobeView. After this PR, it creates sublayers with coordinateSystem: 'OSMTile512' in all viewports.

Antarctica, coordinateSystem: 'EPSG:3031' (Stereographic) + GlobeView

France regions, coordinateSystem: 'EPSG:2154' (Lambert-93) + MapView

Switzerland cantons, coordinateSystem: 'EPSG:2056' (LV95) + CustomProjectionView toCrs: 'EPSG:8857' (Equal Earth)

Change List

• Accept arbitrary CRS strings in Layer.coordinateSystem
• Resolve source CRS before initializing or updating layers
• Track per-layer preprojection and packed-coordinate CRS
• Keep shader-supported coordinates untransformed during attribute packing
• Load MVT geometry consistently in OSMTile512
• Derive subdivision steps from source CRS units and viewport resolution
• Tessellate polygons in the viewport’s target CRS
• Unit tests, render tests, docs, and upgrade guide

---

Note

High Risk
Breaking v10 changes across projection, layer initialization, multi-view filtering, and exported constants, with broad impact on aggregation, picking, and tiled layers.

Overview
Layers can declare data CRS with strings (EPSG/PROJ, legacy aliases like 'meter-offsets') instead of the removed COORDINATE_SYSTEM export. The layer manager resolves CRS asynchronously, blocks init/update until ready, and tracks source vs packed attribute CRS plus CPU preproject / unpreproject when the view shader cannot consume the source CRS directly. coordinateOrigin applies in source CRS before conversion for absolute CRSs.

Projection pipeline refactor: viewport getPreprojection(sourceCrs) replaces ad-hoc preproject flags; shader uniform coordinateSystem → coordinateFrame (identity/geodetic/projected/geocentric). Multi-view: first viewport allowed by layerFilter (screen pass) seeds a layer’s projection context; draw activates viewport once per layer. resolution subdivision is earth-circumference–based (opt-in, including Globe); layers use getSubdivisionStep(sourceCrs).

Aggregation, tiles, picking: aggregation/custom-projection paths use project.isCustomProjection and layer preprojection state; hexagon pick adds position in source CRS (nullable); PickingInfo.coordinate may be null. MVT documents/uses tile-local OSMTile512; v10 examples switch to string coordinate systems.

Docs/upgrade guide cover v10 viewport CRS, Globe position, and migration from constants.

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[cursor]

Stale Bugbot comment from a previous run.

[greptile-apps]

Confidence Score: 3/5

[High impact] The changes reach deck.gl’s shared projection path across views and layer types.

Fix the stale polygon transforms and the outstanding binary globe tile winding issue before merging.

Findings

1.  Polygon transforms stop working ▶

Summary

Layers can declare arbitrary source CRSs, with CPU conversion when the view cannot use those coordinates directly.

• Layers can use a source coordinate system that differs from the viewport.
• Viewport resolution controls geometry detail across coordinate systems.
• MVT sublayers use tile-local coordinates in every viewport.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart LR
  A[Source coordinates] --> B[Apply layer transforms]
  B --> C{View accepts source CRS?}
  C -->|Yes| D[Keep native attributes]
  C -->|No| E[Convert positions on CPU]
  D --> F[Triangulate with transformed coordinates]
  E --> F
  F --> G[Draw polygon]

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_{Reviews (8) · Last reviewed commit: "Invalidate triangulation when modelMatri..." · Reviewed by Greptile}

[coveralls]

coverage: 84.132% (+0.4%) from 83.717% — codex/source-crs-resolution into master

[kylebarron]

• Accept arbitrary CRS strings in Layer.coordinateSystem

The typedef of CRS definition should at least include objects to support PROJJSON, a more modern description of CRS than the relatively fickle and outdated proj strings

[cursor]

Stale Bugbot comment from a previous run.

[cursor]

Stale Bugbot comment from a previous run.

[cursor]

Stale Bugbot comment from a previous run.

[ibgreen]

Thanks for the substantial work on the CRS refactor. I’m requesting one correctness fix before approval: globe polygon triangulation still becomes invalid when a shader-side layer transform moves the polygon across the globe. The current code even documents this assumption, but modelMatrix and coordinateOrigin are public layer props and can change without rebuilding indices. Please make the temporary coordinates used for geocentric winding include the same transforms as rendering, and invalidate/retriangulate when those transforms change. A north-to-south move is a concrete case where triangles become inward-facing and disappear under back-face culling.

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

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