Fix #220: antimeridian wrap in point-mode loadViewportSamples()

EXPLORER_STATE.md

@@ -525,27 +525,30 @@ the page and count queries now include
 dateline-crossing handling, including the post-padding wrap case
 where a non-wrapping rect spills past ±180 after the 30% expansion).
 
-**Known pre-existing wrap bug NOT fixed in this PR.**
+**Antimeridian wrap bug — FIXED in #220 (was scoped out of #219).**
 `loadViewportSamples()` in `zoomWatcher` (the point-mode sample
-loader) has its own padding logic that does *not* split the
+loader) previously had its own padding logic that did *not* split the
 longitude predicate when the padded rectangle wraps the
 antimeridian — `bounds.east - bounds.west` is meaningless for a
-wrapping viewport, and the resulting single `BETWEEN` clause can
-return zero matches. This PR's table queries now route through
+wrapping viewport, and the resulting single `BETWEEN` clause
+returned zero matches. #219's table queries route through
 `viewerBboxSQL()` and split the wrapped predicate correctly, so the
-**table is fine** at the dateline; the bug is now only in the
-point-mode count (phase-msg "Samples in View"). At wrapping
-viewports the two surfaces will therefore diverge: table shows the
-correct row set, phase-msg can read zero or undercount. Scoped out
-as a follow-up because the user's primary complaint (table=6M vs
-phase-msg=153 at Crete) is unrelated to the dateline. Right fix is
-to share the `viewerBboxSQL`-style normalization with point-mode.
+**table was already fine** at the dateline; the bug remained only in
+the point-mode loader + its count (phase-msg "Samples in View",
+computed off the same WHERE). #220 fixes it by routing
+`loadViewportSamples()` through the SAME `viewerBboxSQL('latitude',
+'longitude', VIEWPORT_PAD_FACTOR)` helper, so point mode, the
+"Samples in View" count, and the table now all use the identical
+wrap-aware, post-padding-normalized bbox. (Originally scoped out of
+#219 because the user's primary complaint — table=6M vs phase-msg=153
+at Crete — was unrelated to the dateline.)
 The shared `VIEWPORT_PAD_FACTOR` (0.3) is applied by the table query,
 the point-mode loader, and the cluster-mode `countInViewport()` call
 sites, so all three surfaces use the same padded bbox for their "in
 view" counts in the non-dateline, non-facet-filtered case. Caveats
-called out below: point mode still has the antimeridian padding bug
-(#220), cluster counts are H3-cell-granularity approximations, and
+called out below: the antimeridian padding bug is now fixed (#220 —
+point mode shares `viewerBboxSQL`), cluster counts are
+H3-cell-granularity approximations, and
 cluster H3 loads don't apply the material/context/object-type facet
 filters — so under those conditions the counts can still diverge
 independent of this PR. Issue #221 was three sources of divergence:

explorer.qmd

@@ -1323,6 +1323,8 @@ function paddedViewportBounds(padFactor) {
 // - tableView (PR #219): scopes the samples table to the current viewport
 //   so "samples in view" in cluster/point mode == table row count.
 // - doSearch('area') (#178 light path): exact-viewport text search.
+// - loadViewportSamples() (#220): point-mode sample loader + "Samples in View"
+//   count, so point mode uses the same wrap-aware bbox as the table.
 function viewerBboxSQL(latCol, lngCol, padFactor) {
     const b = paddedViewportBounds(padFactor);
     if (!b) return null;
@@ -3024,17 +3026,19 @@ zoomWatcher = {
         const bounds = getViewportBounds();
         if (!bounds) return;
 
-        // Fetch with VIEWPORT_PAD_FACTOR (30%) padding so this fetch
-        // covers the same bbox as the table query and the cluster-mode
-        // "Samples in View" count (issue #221).
-        const latPad = (bounds.north - bounds.south) * VIEWPORT_PAD_FACTOR;
-        const lngPad = (bounds.east - bounds.west) * VIEWPORT_PAD_FACTOR;
-        const padded = {
-            south: bounds.south - latPad,
-            north: bounds.north + latPad,
-            west: bounds.west - lngPad,
-            east: bounds.east + lngPad
-        };
+        // #220: bbox via the shared `viewerBboxSQL()` (VIEWPORT_PAD_FACTOR padding),
+        // the SAME helper the table uses (since #219). The previous inline padding
+        // emitted a single `longitude BETWEEN padded.west AND padded.east`, which is
+        // WRONG at the antimeridian: a viewport that wraps the dateline has
+        // west > east (and, post-padding, `bounds.east - bounds.west` is negative, so
+        // the inline lngPad math was meaningless too), so `BETWEEN a-larger AND a-
+        // smaller` matched ZERO rows — point mode + the "Samples in View" count
+        // (computed off the same WHERE) read 0 / undercounted near the dateline while
+        // the table (via viewerBboxSQL) showed the correct set. viewerBboxSQL emits
+        // the split `(lng BETWEEN west AND 180 OR lng BETWEEN -180 AND east)` for the
+        // wrap case and also normalizes post-padding overflow back into [-180,180].
+        const bboxSQL = viewerBboxSQL('latitude', 'longitude', VIEWPORT_PAD_FACTOR);
+        if (!bboxSQL) return;  // off-globe (rare) — same bail as the !bounds guard
 
         updatePhaseMsg('Loading individual samples...', 'loading');
 
@@ -3047,8 +3051,7 @@ zoomWatcher = {
             // POINT_BUDGET-worth of rows the LIMIT returns is undefined and
             // can differ across browsers/sessions for the same query.
             const whereClause = `
-                WHERE latitude BETWEEN ${padded.south} AND ${padded.north}
-                  AND longitude BETWEEN ${padded.west} AND ${padded.east}
+                WHERE 1=1${bboxSQL}
                   ${sourceFilterSQL('source')}
                   ${facetFilterSQL()}
                   ${searchFilterSQL('pid')}