feat: reprojector initial-triangulation seed + clamp Web Mercator meshes to ±85.051°#574
Merged
Conversation
Design for rendering imagery crossing ±180° in Web Mercator (issues #171, #366). Splits a crossing tile at the antimeridian into west/east pieces so each reprojects as a normal non-crossing tile — avoiding the proj4-rewrap unwrap that prior attempts (#353/#374/#269) stumbled on. Generalizes the RasterReprojector to accept a delaunator-shaped initial-triangulation seed (subsuming #351 uvBounds / pole clamp), splits in _renderSubLayers into two single-mesh RasterLayers, and uses a two-box bounding volume composing with the merged world-copy traversal (#518). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…ted cuts - Use the vendored geotiff-test-data antimeridian.tif fixture (42x42 EPSG:4326, crosses -180 at column 24) as the primary deterministic crossing test. - Handle slanted (rotated-geotransform) cuts, not just vertical: any straight cut yields convex pieces delaunator triangulates exactly; error only on curved/concave cuts. createInitialConditions is therefore part of the MVP crossing path. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…d seed) Add the InitialTriangulation type and a tree-shakeable createInitialConditions helper that builds a Delaunay seed from a UV point set. delaunator is confined to its own module (initial-conditions.ts); delatin.ts does not import it and the package is sideEffects:false, so it tree-shakes out for consumers that don't use it. Foundation for antimeridian cut-in-two and the sub-domain capability in #351. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…hip a wrapper Per review: a one-line delaunator wrapper isn't worth a runtime dependency. Expose only the InitialTriangulation type and show the delaunator one-liner in its docstring. delaunator moves to devDependencies — used by tests to validate winding compatibility, not shipped to consumers. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…esign raster-reproject exposes only the InitialTriangulation type + documents the delaunator one-liner; delaunator is a dev/test dep (winding validation), not shipped. Runtime seed-building for crossing tiles is the deck.gl-raster builder's job (follow-up plan). Mark stage 1 done. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…ulation Generalize the constructor to accept an optional initialTriangulation seed (delaunator's data shape), defaulting to a hardcoded unit-square seed so behavior is unchanged and the package needs no runtime triangulation dep. Refinement only ever splits existing triangles, so a sub-domain seed confines the mesh to that region. Tests build seeds via delaunator (the documented pattern) to validate winding compatibility + sub-domain confinement. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Build an axis-aligned 2-triangle rectangle seed for a UV sub-rectangle (no delaunator, runtime-safe). UNIT_SQUARE_SEED is now rectangleSeed(0,0,1,1). Used to clamp a mesh to a UV band — e.g. the valid Web Mercator latitude band (#182 / #351) — and reused by the antimeridian vertical-cut case. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Pure helper that returns a rectangleSeed clamping a north-up geographic tile's reprojection mesh to the Web Mercator latitude band, or undefined when no clamp is needed/possible (rotated/projected tiles, fully-polar tiles). Avoids the degenerate near-pole triangles from #182 / #351. Unit-tested with synthetic corner latitudes. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Wire the reprojector seed through the render path: RasterLayer gains an initialTriangulation prop (passed to RasterReprojector, regenerated on change); getTileMetadata computes a per-tile _webMercatorReprojectorSeed via webMercatorClampSeed; _renderSubLayers passes it in the Web Mercator branch only (globe shows the poles, full mesh). Fixes the degenerate near-pole triangles for EPSG:4326 imagery reaching ±90° (#182 / #351). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
kylebarron
changed the title
kylebarron
commented
May 27, 2026
Rename webMercatorClampSeed → webMercatorInitialTriangulation and the tile metadata field _webMercatorReprojectorSeed → _webMercatorInitialTriangulation, for consistency with the InitialTriangulation type and the RasterLayer.initialTriangulation prop (drops the ad-hoc 'seed'/'ReprojectorSeed' terms). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…Triangulation Verb-prefixed name for the builder (was webMercatorInitialTriangulation); the tile metadata field stays _webMercatorInitialTriangulation. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Active verb name for the helper that triangulates a UV rectangle into an InitialTriangulation; internal UNIT_SQUARE_SEED -> UNIT_SQUARE_TRIANGULATION; test file renamed to match. Updates the deck.gl-raster clamp caller too. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Completes the rename (a657eb8 only moved the test file): rectangleSeed -> triangulateRectangle in delatin.ts + index export + the renamed test, and the deck.gl-raster web-mercator-clamp caller. UNIT_SQUARE_SEED -> UNIT_SQUARE_TRIANGULATION. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Before:
After:
Closes #351
Summary
Generalizes
RasterReprojectorto start from an arbitrary initial triangulation instead of always the full unit square, and uses that to clamp reprojection meshes to the valid Web Mercator latitude band (±85.051°). This fixes the degenerate near-pole triangles / non-convergence for EPSG:4326 imagery reaching ±90° (#182, #351): beyond ±85.051°makeClampedForwardTo3857collapses every row onto the same edge Y, so the old mesh smeared the polar caps onto the map edge and the reprojector burned all 10k refinement iterations.It's also the foundation for rendering imagery across the antimeridian (cut-in-two): the same seed will let a crossing tile be split into two normal pieces. That implementation is a follow-up PR; the design spec is included here for context.
What's here
@developmentseed/raster-reprojectinitialTriangulationseed ({ uvs, triangles, halfedges }— delaunator's shape), defaulting to the existing unit square (behavior unchanged). Refinement only splits existing triangles, so a sub-domain seed confines the mesh to that region.triangulateRectangle(uMin, vMin, uMax, vMax)for axis-aligned sub-rectangle seeds (no runtime triangulation dependency).InitialTriangulationtype; its docstring shows the delaunator one-liner. delaunator is a dev/test dependency only (validates winding compatibility) — not shipped.@developmentseed/deck.gl-rastercreateInitialWebMercatorTriangulation(cornerLats)— a north-up geographic tile past ±85.051° → a clampedtriangulateRectangle; otherwiseundefined(rotated/projected/in-bounds/fully-polar → full mesh).RasterLayergains aninitialTriangulationprop (mesh regenerates on change).getTileMetadatacomputes a per-tile_webMercatorReprojectorSeed;_renderSubLayersapplies it in the Web Mercator path only (globe renders the full mesh — it shows the poles).Docs
dev-docs/specs/2026-05-27-antimeridian-crossing-tile-design.md— the cut-in-two design (this PR is its foundation; antimeridian rendering follows separately).Test plan
raster-reprojectunit tests — default seed unchanged, delaunator-seed winding, sub-domain confinement,triangulateRectangledeck.gl-rasterunit tests —createInitialWebMercatorTriangulationband math + gatingcog-basic, EOxCloudless global ±90°) — mesh ends cleanly at ±85.051° matching the basemap; "mesh refinement did not converge" warning gone; high-latitude features (northern Norway) align with country outlinesWritten by Claude on behalf of @kylebarron