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fix(analysis): Simplify takes each vertex's tolerance at its own latitude (#1033) - #1808
Simplify converted its tolerance from meters once per feature, at the feature's label point, so a feature spanning many latitudes was simplified more than asked toward the equator. The user guide gave the example: a polar cap from 60°N, at 3 km, could move its 60°N vertices about 17 km. Now each vertex's tolerance is taken where it is (at the latitude nearest the equator between the vertex and the chord it's measured to, still at most 85°'s scale), so no part of a feature is simplified more than asked: no vertex moves farther on the ground than the tolerance. Near a long stretch reaching toward the equator, a feature can be simplified a little less than asked; the guide says so.
It's still Douglas–Peucker: of the vertices beyond their tolerance, the one farthest from the chord on the ground splits the run. At one scale it matches geo's Simplify, including which of two equally far vertices it keeps. The tolerance is also taken 0.34% smaller, the WGS 84 ellipsoid's largest radius of curvature over the sphere's, so the bound holds on the ellipsoid and not only on the sphere. That margin changes every feature's result slightly, wherever it is: a vertex within 0.34% of the tolerance now stays. A tolerance of 0 now leaves every feature exactly as it is; before, it still sent them through the analysis plane and back, which moved a latitude past ±90° to the pole.
Cancel is looked at every 65,536 distances, inside a feature and inside each scan, so one large feature can't hold the run. Where a run can't be canceled, the work is bounded: a run that would take more than 256 distance checks a vertex (only a hostile line, such as a long spiral, comes near it) keeps the vertices of what's left rather than running on, and the tool says how many features that happened to. A run that can be canceled takes no cap, as other tools'. Before, such a line took time growing with the square of its length, with no way to cancel inside the feature.
Things it now says instead of doing silently:
A feature without geometry was left out of the output with no word. It still is, and the tool says how many, as Clip does.
A line or polygon with a missing coordinate, or a longitude too far out for the analysis plane (infinite there, or so large its squared distances would overflow), is left exactly as it was, and the tool says how many.
A latitude past ±90° is taken as the pole, as before, and the tool counts those vertices, as Minimum Bounding Geometry does.
A line part of fewer than 2 vertices beside a longer one was dropped with no word; the tool now says how many.
The polar notice now starts with "Simplify:", like the others. It keeps #1746's parallel structure: each feature is simplified on its own, with Cancel and progress between features.
Testing
simplify_takes_each_vertex_tolerance_at_its_own_latitude: a polygon from 60°N to 89°N with a bump at 60°N. At 3 km, a 5 km bump stays and a 1 km bump goes. It fails on main, where the tolerance taken at the feature's middle is wider than the 5 km bump.
simplify_moves_no_vertex_farther_than_asked_poleward_of_its_chord: along the 80th parallel at 25 km, a vertex 25.15 km north stays (taken at its own latitude alone, it would have gone) and one 24.5 km north goes.
simplify_coords_matches_douglas_peucker_at_one_scale: with every vertex at one scale (beyond 85°), the result equals geo's Simplify on a zigzag at five tolerances, on two peaks exactly as far from the chord (the tie decides which stays), and at a tolerance of 0 with collinear and repeated vertices.
simplify_holds_its_bound_on_wgs84: at 60°N a vertex 999.1 m off on the sphere but about 1,001.6 m on WGS 84 stays at a 1 km tolerance.
simplify_coords_looks_at_cancel_inside_a_feature: canceled, a 200,000-vertex line stops in its first scan and keeps its vertices, without calling it a work cap; under a run that can be canceled there's no cap even with the work cut to one check a vertex.
simplify_coords_keeps_vertices_when_its_work_runs_out: with the work cut to one check a vertex, a 2,000-vertex zigzag keeps more vertices than with the work allowed, every vertex beyond its tolerance among them, and says it ran out.
simplify_says_what_it_leaves_alone_and_out: lines with a NaN vertex or a longitude of 1e308 or 1e200 come out exactly as they went in and are counted; a latitude of 95° and a feature without geometry each give their notice; at a tolerance of 0 every feature comes out exactly as it went in, with no notice about them; a clean layer gives none of them.
simplify_says_how_many_short_line_parts_it_left_out: a one-vertex part and an empty one beside a longer part are counted.
simplify_rings_do_not_grow_with_tolerance now checks each vertex against its own latitude's tolerance.
cargo xtask ci and cargo build --target wasm32-unknown-unknown -p rustgis-web pass.
Geometry simplification now accounts for local ground scale along each line or polygon ring, keeping vertex movement within the requested distance. Simplification may be less aggressive near the equator and beyond 85.05° latitude.
Invalid coordinates leave affected geometries unchanged. Short line parts are omitted when longer parts are simplified, and processing limits prevent excessive work.
Results report capped features, features extending beyond 85.05°, missing geometries, and omitted short line parts.
Documentation
Updated the analysis guide to explain tolerance behavior and result counts.
…tude (opengeos#1033)
Simplify converted its tolerance into the plane once per feature, at its
label point's latitude, and applied it to every vertex, so a feature
spanning many latitudes was simplified farther than asked on its
equatorward side: a cap from 60°N to the pole at 3 km could move vertices
along 60°N some 17 km on the ground. Douglas–Peucker now keeps a vertex
when it lies farther from the chord than its own tolerance, converted at
its own latitude (still at most 85°'s scale, so beyond 85.05° less is
simplified away than asked, as the tool says). Worked with a stack, not
recursion.
Test: a polygon from 60°N to 89°N keeps a 5 km bump along 60°N at 3 km
(which one tolerance at its label point would have taken) and drops a
1 km one. The reference corpus is unchanged.
Simplify now uses iterative Douglas–Peucker simplification with per-vertex ground-distance tolerances and a limit on distance checks. Feature processing reports additional unchanged, omitted, and capped cases. Tests and user documentation cover the updated behavior.
The coordinate simplifier uses per-vertex latitude scales, preserves endpoints, and limits distance checks. Tests cover tolerance bounds, capped work, invalid coordinates, and ring behavior.
Geometry handling and feature reporting crates/analysis/src/tools.rs, docs/user-guide/analysis.md
Geometry and line parts are simplified through a checked path. Feature processing reports capped, invalid, poleward, missing, and omitted geometries. Tests and documentation describe these outcomes.
sequenceDiagram
participant simplify_on
participant simplify_checked
participant simplify_coords
simplify_on->>simplify_checked: simplify each feature
simplify_checked->>simplify_coords: simplify line parts and polygon rings
simplify_coords-->>simplify_checked: return coordinates and cap status
simplify_checked-->>simplify_on: return geometry and cap status
Loading
Possibly related issues
opengeos/RustGIS#1033: The changes address Simplify’s polar behavior, but do not change Clip, Dissolve, or the other tools in the issue.
opengeos/RustGIS#1811: This PR adds the Simplify notices that the issue depends on; its package and layout callers are not changed here.
Possibly related PRs
opengeos/RustGIS#911: This PR changes the same ring-simplification path and related tests.
Suggested reviewers:giswqs
Merge Risk: Low · up to 46ab1
Simplify now uses per-vertex ground tolerances, with a work cap and cancellation checks inside long spans. A single feature made of a very large number of tiny parts can still delay Cancel until that feature finishes. This is a bounded issue and does not affect results; either add a check between parts or document the gap before or after merge.
Pre-merge checks: 4
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The title names the main change: Simplify now takes each vertex's tolerance at that vertex's own latitude, matching the summary's per-vertex tolerance change. It is specific and descriptive. The conve…
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The description is thorough and covers the change. It explains the move from a single label-point tolerance to per-vertex tolerance, the zero-tolerance behavior, the 256-check work cap with cancellati…
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Explanation
The title names the main change: Simplify now takes each vertex's tolerance at that vertex's own latitude, matching the summary's per-vertex tolerance change. It is specific and descriptive. The conventional-commit prefix and issue number are minor noise but do not affect relevance.
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Explanation
The description is thorough and covers the change. It explains the move from a single label-point tolerance to per-vertex tolerance, the zero-tolerance behavior, the 256-check work cap with cancellation every 65,536 distances, and the new notices and counts for features or parts left out or unchanged. It lists named tests and the CI commands run. The template's Summary, Testing, UI evidence, and Related issue sections are all present. The UI evidence section states no visible UI change, which matches the template's allowance. The Related issue section says 'Part of #1033.' The description is mostly complete and clear.
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A rabbit traced the latitude line, Then measured each vertex by design. The endpoints stayed, the checks stayed bound, While careful rings went round and round. “Simplify,” it said, “and keep the ground!”
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Cancel is not looked at inside a feature's run (medium confidence). simplify_coords_within does up to 256 × n distance checks per part (each a hypot), and the only Cancel check is in try_map_on between features. A single 1–2 million vertex feature can therefore run for seconds with Cancel ignored. AGENTS.md asks that a long step without a check be said in its doc comment, and this one is not. Either make the span loop return Result and call crate::control::check()? once per popped span (propagating through simplify_ring and simplify_checked), or add a sentence to the simplify_coords doc comment stating the per-feature bound and that Cancel is only seen between features.
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Fair point. Fixed in 236d71b: a run now looks at Cancel every 65,536 distances, so one big feature doesn't hold the run. When it's canceled, the spans still open keep their vertices and the run stops as canceled. The work per run was already capped at 256 distance checks a vertex.
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Doc contradicts the code (high confidence). "A tolerance of 0 leaves every feature as it is" is not true: a feature without geometry is left out of the output at tolerance 0 too (the test simplify_says_what_it_leaves_alone_and_out gets 4 features back from 5 inputs at 0). The PR body repeats the same claim. Only the geometries are left as they are.
Suggested change
tool says how many features reach that far. A tolerance of 0 leaves every feature as it is.
tool says how many features reach that far. A tolerance of 0 leaves every geometry as it is.
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Right, fixed in 236d71b. The guide now says a tolerance of 0 leaves lines and polygons as they are, and that features without geometry are left out either way.
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Notices stay in simplify_on; public callers get the new partial results silently (low confidence, partly pre-existing). simplify_geometry is pub and is also called by engine/src/cmd/items.rs:736 (mobile package, which already simplifies silently) and engine/src/cmd/layout.rs:1726. Now that it can return a capped result (more vertices kept than asked) or leave a geometry unchanged because of a missing coordinate, those callers have no way to say so. The mobile package path was already silent before this PR, so it is not new, but the capped path is. Consider returning Simplified (or its flags) from a public function and having items.rs pass the counts to Session::notify.
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Agreed it's a gap, but it's older than this PR: the mobile package and the layout locator already simplified without saying anything. I'd rather fix that on its own than widen this one, so I'll file it separately.
I read the diff, the base-branch AGENTS.md, and the surrounding code (geom projection, convert.rs, the engine callers). I could not compile or run the tests here, so the findings rest on reading. Nothing found is a correctness bug in the core Douglas–Peucker logic. I checked the per-vertex scale logic (the equator straddle case and the monotonic-in-|lat| argument), the index and budget arithmetic, the NaN and overflow paths, and the message wiring, and found no defect in them.
Bugs
None confirmed.
Security
None found.
Performance
None found. Work is bounded at 256 × n distance checks per part, and the per-vertex latitude is computed once per vertex.
Quality
Cancel is not checked inside a single feature's run. The Douglas–Peucker loop in simplify_coords_within has no control::check, and the doc comment does not say so. Medium confidence. (crates/analysis/src/tools.rs:3814)
simplify_geometry is public, and its callers (items.rs:736, layout.rs:1726) get the new capped and unchanged results without any notice. Low confidence, partly pre-existing. (crates/analysis/src/tools.rs:3904)
AGENTS.md
The docs say "a tolerance of 0 leaves every feature as it is", but a feature without geometry is still dropped at 0. High confidence. (docs/user-guide/analysis.md:338, suggestion posted)
Nits left for the release quality pass: the five-element tuple in simplify_on, and merc_scale(0.0) being recomputed per vertex in the straddle case.
Prior concerns: none. prior-reviews.json had no threads, so I left 0 earlier concerns alone.
Not verified: I could not confirm the claim that only hostile lines reach the 256-checks-per-vertex cap, and I did not run the new tests.
Note: the first inline comment includes a trailing HTML comment line (<!-- not a quality nit… -->) that I did not intend. It is invisible when rendered.
Change size
Compared with main (merge base ba2be56 to PR head a312236), the whole PR.
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Inline comments:
Review comments at @crates/analysis/src/tools.rs:
- Line 3849: Update the simplification tolerance check at `if d <= tol_m * s` to
use a conservative WGS 84 scale so the bound respects ground distance rather
than spherical projected distance. Verify the resulting deviation using WGS 84
distances and preserve vertices whose ground-distance deviation exceeds `tol_m`.
- Line 4045: Update the pole-conversion notice in the simplify_checked flow to
count only vertices whose geometry was actually converted; short lines retained
unchanged after from_line returns None must not be reported as taken to the
pole. Update the corresponding user guide text to match this behavior.
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…ound on WGS 84, and counts only vertices it takes to a pole
A run looks at Cancel every 65,536 distances, so one large feature no longer
holds the run until it's done. The tolerance is taken 0.34% smaller, the
ellipsoid's largest radius of curvature over the sphere's, so no vertex moves
farther than asked on WGS 84 either. A geometry given back as it was moved
nothing, so its vertices past a pole aren't counted as taken there, and a
line's past-pole vertices are counted only in the parts it keeps. The guide
says a tolerance of 0 leaves lines and polygons as they are; features
without geometry are still left out.
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The WGS 84 factor changes every feature's result, not only multi-latitude ones (high confidence on the fact; the PR text is what's wrong). This line scales every tolerance by about 0.9966, so at the equator, where merc_scale(0) is 1, a vertex 997 m off a chord with a 1,000 m tolerance is now kept, and before it was removed. The PR body says "Results change only for features that span a range of latitudes" and "A feature at one latitude gives exactly what it gave before", and the guide doesn't mention a tighter tolerance. The _matches_douglas_peucker_at_one_scale test already multiplies by SPHERE_TO_WGS84, so the author knows. Either correct the PR body and the guide to say the tolerance is tightened by about 0.34% everywhere (so the ellipsoid bound holds), or say why a single-latitude result should change at all.
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You're right, the description overstated that. I've updated it: the 0.34% margin changes every feature's result slightly, wherever it is. What still matches geo at one scale is the method, ties included.
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The new in-feature Cancel has no test (high confidence). The tests added here cover the work cap (simplify_coords_keeps_vertices_when_its_work_runs_out), but no test cancels a run partway through a feature. simplify also isn't in the long-command list in engine/src/tests.rs::long_commands_stop_when_cancelled_while_they_run, though its work grows with input. Add a unit test that runs a single feature over 65,536 distances with a Control that is cancelled at start and asserts the run ends as cancelled, and add simplify to the engine list. AGENTS.md asks that a long loop's Cancel be shown by a passing test, not only by reading it.
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Added in 46ab1d7: simplify_coords_looks_at_cancel_inside_a_feature cancels a 200,000-vertex run and checks that it stops in its first scan, keeps its vertices, and isn't counted as a work cap. Simplify is also already in the engine's long-commands Cancel test.
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Longitudes whose plane squares overflow pass as "not broken" and are kept silently (medium-low confidence; hostile input only). The check only catches a non-finite plane coordinate, so a longitude near 1e200 passes. There dx * dx (and the numerator of t) overflows to inf, t becomes NaN, d becomes NaN, and every interior vertex is kept with no notice. That contradicts the doc and PR claim that such a feature "is left exactly as it was, and the tool says how many". No panic, but the result is silent. Suggested fix: also treat plane coordinates beyond a bound where the squares stay finite (for example |x| or |y| above 1e150) as broken, and add a test with a longitude of 1e200 expecting the "left as they were" notice.
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Fixed in 46ab1d7. A plane coordinate beyond 1e150 m (a longitude past about 1e143°) now leaves the feature as it was, counted with the others, since its squared distances would overflow. The test covers 1e200.
The WGS 84 factor (SPHERE_TO_WGS84, applied at crates/analysis/src/tools.rs:3808) tightens every tolerance by about 0.34%, not only features that span latitudes. A feature at the equator changes too, which contradicts the PR body's "results change only for features that span a range of latitudes" and "a feature at one latitude gives exactly what it gave before". Confidence: high on the fact. Inline comment posted.
Longitudes around 1e149° to 1e302° pass the "broken" check because their plane coordinates stay finite, but the squared distances overflow to NaN and every interior vertex is kept with no notice. This contradicts the "left exactly as it was, and counted" claim. Hostile input only, no panic. Confidence: medium-low. Inline comment posted at tools.rs:3948.
Security
None found.
Performance
None found. The 256·n distance budget and the 65,536-distance Cancel granularity look bounded. I did not measure them.
Quality
The new in-feature Cancel has no test, and simplify is not in the long-command list in engine/src/tests.rs::long_commands_stop_when_cancelled_while_they_run. Confidence: high. Inline comment posted at tools.rs:3828.
Nit (group): the past_pole comment says counted vertices are "those in what's kept", but the polygon branch counts every input coordinate, including ones simplification drops. Left for the release quality pass.
AGENTS.md
Public simplify_geometry callers (items.rs:736, layout.rs:1726) still return capped or unchanged results silently. The author has already said this will be filed separately. Not repeated here.
Prior concerns left alone: 5. Four are addressed in the current head: the in-feature Cancel (236d71b), the WGS 84 bound (SPHERE_TO_WGS84), the pole notice for unchanged geometry, and the tolerance-0 doc. The fifth is the public callers above, which the author deferred.
Change size
Compared: the whole PR against main (merge base ba2be56 to PR head 236d71b). 2 files changed (0 added, 2 modified, 0 removed, 0 renamed). Size before 912.1 KB, size after 935.5 KB, total change +23.5 KB.
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Fix comments: Fix CodeRabbit comments on this PR
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Inline comments:
Review comments at @crates/analysis/src/tools.rs:
- Around line 3827-3830: Update the span distance-scan loop near since_check to
count completed distance calculations and check cancellation after each block of
65,536 calculations, resetting the counter at each check. Do not rely only on
the existing check before scanning a span; preserve the existing cancellation
behavior elsewhere.
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…p where it can be canceled, and leaves alone longitudes whose squares overflow
Cancel is looked at every 65,536 distances inside a span's scan, not only
between spans, so a long span can't hold the run. A run someone can stop
takes no work cap, as other tools'. A plane coordinate beyond 1e150 m (a
longitude past about 1e143°) leaves its feature as it was and is counted,
as its squared distances would overflow. Tests: a canceled 200,000-vertex
run keeps its vertices without calling it a cap; the WGS 84 bound at 60°N.
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Bug (low impact): the past-pole count includes vertices the simplification removes, so the notice overstates what was "taken as that pole". The count runs over the input geometry's coordinates in parts of 2 or more (and over every coordinate of a polygon), not over the output. A vertex beyond 90° that Douglas–Peucker drops is still counted, and the comment above says the counted vertices are "those in what's kept", which is not what the code does. Example: a line with three collinear vertices at 95°N, where the middle one is removed, reports 3 vertices taken to the pole, but only 2 are in the output.
Suggested fix: count from the output instead. For example, have simplify_checked return the count of kept vertices with |lat| > 90 from the keep flags, or recount the returned s.geometry against past. Then correct the comment. Confidence: high on the code reading, low impact.
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Re-raising a concern with new evidence (the earlier thread was answered with "older than this PR"). The author's answer covers only the gap that already existed in the mobile package and layout callers. This PR adds two new silent results on the same public path. First, a line or polygon with a missing or out-of-range coordinate is returned unchanged with no notice. Second, a run that hits the work cap (when no stoppable control is installed) keeps extra vertices with no notice. Callers in engine/src/cmd/items.rs:736 and engine/src/cmd/layout.rs:1726 cannot report either. Both are results the "Never silent" rule covers, so the fix from the earlier thread still applies: return the Simplified flags, or otherwise pass the counts up, and notify. Confidence: medium. I have not traced whether those callers run under a stoppable control.
The past-pole count in simplify_on counts input vertices, not kept ones, so a removed vertex beyond 90° still counts as "taken as that pole". The comment says the count covers kept vertices, which is wrong. Low impact on the notice, not on the output. Confidence: high on the reading. (Inline, tools.rs:4026)
Security
None found. The new code uses get, let … else, and bounded arithmetic. Coordinates are capped at 1e150, so the squared distances stay finite.
Performance
None blocking. Each vertex is transformed about three times, and the geometry is compared once more with !=. All linear. The work is capped only when no stoppable control is installed, and a stoppable run checks Cancel every 65,536 distances.
Quality
The public simplify_geometry now returns capped or unchanged results with no notice. The earlier thread was answered with "older than this PR," but the capped and broken paths are new, so I re-raised it. Confidence: medium. I did not trace whether items.rs:736 or layout.rs:1726 run under a stoppable control. (Inline, tools.rs:3928)
AGENTS.md
No unwrap, expect, panic, or unsafe in non-test code. Engine simplify is in the long-command Cancel list. In-feature Cancel has a test. Lossy and clean inputs both have tests. The new messages use plain format!, which matches the rest of the analysis crate, which has no i18n.
Checked and found correct
The per-vertex tolerance uses the minimum scale over the vertex and the chord ends, with a straddle check at the equator. This bounds the ground deviation.
The WGS 84 factor, a/c ≈ 0.99665, matches the ratio of the largest radius of curvature to the sphere's radius.
Ties, the cap path, and the cancel path keep the open spans' vertices and mark the run as capped or canceled.
Earlier review threads: 8 concerns left alone because they were already raised and addressed (the WGS 84 margin, the 1e150 overflow, in-feature Cancel, the doc claim for tolerance 0, the pole notice, the WGS 84 test, and the Cancel test). I re-raised one (the public-caller silence) with new evidence.
Change size
Compared with the base branch (merge base ba2be56 to PR head 46ab1d7), the whole PR.
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Fix comments: Fix CodeRabbit comments on this PR
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Inline comments:
Review comments at @crates/analysis/src/tools.rs:
- Around line 3857-3859: Update simplify_checked to check for cancellation
between line parts and polygon rings, rather than relying only on
simplify_coords_within’s per-call counter; if those boundaries cannot support a
check, document the cancellation gap in simplify_checked’s doc comment.
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Summary
Simplify converted its tolerance from meters once per feature, at the feature's label point, so a feature spanning many latitudes was simplified more than asked toward the equator. The user guide gave the example: a polar cap from 60°N, at 3 km, could move its 60°N vertices about 17 km. Now each vertex's tolerance is taken where it is (at the latitude nearest the equator between the vertex and the chord it's measured to, still at most 85°'s scale), so no part of a feature is simplified more than asked: no vertex moves farther on the ground than the tolerance. Near a long stretch reaching toward the equator, a feature can be simplified a little less than asked; the guide says so.
It's still Douglas–Peucker: of the vertices beyond their tolerance, the one farthest from the chord on the ground splits the run. At one scale it matches
geo's Simplify, including which of two equally far vertices it keeps. The tolerance is also taken 0.34% smaller, the WGS 84 ellipsoid's largest radius of curvature over the sphere's, so the bound holds on the ellipsoid and not only on the sphere. That margin changes every feature's result slightly, wherever it is: a vertex within 0.34% of the tolerance now stays. A tolerance of 0 now leaves every feature exactly as it is; before, it still sent them through the analysis plane and back, which moved a latitude past ±90° to the pole.Cancel is looked at every 65,536 distances, inside a feature and inside each scan, so one large feature can't hold the run. Where a run can't be canceled, the work is bounded: a run that would take more than 256 distance checks a vertex (only a hostile line, such as a long spiral, comes near it) keeps the vertices of what's left rather than running on, and the tool says how many features that happened to. A run that can be canceled takes no cap, as other tools'. Before, such a line took time growing with the square of its length, with no way to cancel inside the feature.
Things it now says instead of doing silently:
The polar notice now starts with "Simplify:", like the others. It keeps #1746's parallel structure: each feature is simplified on its own, with Cancel and progress between features.
Testing
simplify_takes_each_vertex_tolerance_at_its_own_latitude: a polygon from 60°N to 89°N with a bump at 60°N. At 3 km, a 5 km bump stays and a 1 km bump goes. It fails on main, where the tolerance taken at the feature's middle is wider than the 5 km bump.simplify_moves_no_vertex_farther_than_asked_poleward_of_its_chord: along the 80th parallel at 25 km, a vertex 25.15 km north stays (taken at its own latitude alone, it would have gone) and one 24.5 km north goes.simplify_coords_matches_douglas_peucker_at_one_scale: with every vertex at one scale (beyond 85°), the result equalsgeo's Simplify on a zigzag at five tolerances, on two peaks exactly as far from the chord (the tie decides which stays), and at a tolerance of 0 with collinear and repeated vertices.simplify_holds_its_bound_on_wgs84: at 60°N a vertex 999.1 m off on the sphere but about 1,001.6 m on WGS 84 stays at a 1 km tolerance.simplify_coords_looks_at_cancel_inside_a_feature: canceled, a 200,000-vertex line stops in its first scan and keeps its vertices, without calling it a work cap; under a run that can be canceled there's no cap even with the work cut to one check a vertex.simplify_coords_keeps_vertices_when_its_work_runs_out: with the work cut to one check a vertex, a 2,000-vertex zigzag keeps more vertices than with the work allowed, every vertex beyond its tolerance among them, and says it ran out.simplify_says_what_it_leaves_alone_and_out: lines with a NaN vertex or a longitude of 1e308 or 1e200 come out exactly as they went in and are counted; a latitude of 95° and a feature without geometry each give their notice; at a tolerance of 0 every feature comes out exactly as it went in, with no notice about them; a clean layer gives none of them.simplify_says_how_many_short_line_parts_it_left_out: a one-vertex part and an empty one beside a longer part are counted.simplify_rings_do_not_grow_with_tolerancenow checks each vertex against its own latitude's tolerance.cargo xtask ciandcargo build --target wasm32-unknown-unknown -p rustgis-webpass.UI evidence
No visible UI change.
Related issue
Part of #1033.
Summary by CodeRabbit