Add lasso spatial selection tool to map charts

[lhawkman27]

Summary

• Add a lasso tool to GeoSet map charts enabling users to draw spatial selections (freehand, polygon, circle, rectangle) and export selected features as CSV or Excel
• Supports multi-layer maps with per-layer targeting and a lassoSelectable admin config toggle
• Spatial filtering handles all GeoJSON geometry types: point-in-polygon, geometric intersection for lines, and area-overlap (≥50%) for polygons
• Self-intersecting polygons (common with freehand drawing) are automatically split into valid parts via @turf/unkink-polygon
• Small datasets (≤5000 features) filter synchronously; larger datasets use async batched filtering to prevent UI freezes
• Results bar clamped within map bounds, menu flips when near edge, anchor tracks pan/zoom via geo-coordinate projection
• Export uses an allowlist of Hover Data + Feature Info columns only — internal styling properties are excluded
• Toast notifications for export success/failure
• Draw mode preference persists in sessionStorage across activations
• ARIA attributes on all lasso controls for screen reader accessibility
• Formula injection protection on both CSV and Excel export paths

Focus Score

8/10 — All changes serve the single goal of adding the lasso selection tool. The slight breadth comes from necessarily touching integration points (DeckGLContainer.tsx, Multi.tsx, GeoSetLayer.tsx, DeckSlicesControl) and adding shared infrastructure (hooks, types, utilities) that the feature depends on. Wiki and documentation updates are scoped to the lasso feature.

Detailed Summary of Each File Changed

New Source Files

File	Description
src/components/useLassoLayer.ts	Hook wrapping @deck.gl-community/editable-layers for draw interaction + completed polygon display layers
src/components/LassoDropdown.tsx	Layer picker + draw mode toggle dropdown with ARIA roles
src/components/LassoResultsBar.tsx	Selection count display with export menu (CSV/Excel), clamped positioning, menu flip logic
src/components/icons.tsx	SVG icon components for lasso, freehand, polygon, circle, rectangle, radio, kebab, close, download
src/hooks/useLassoActivation.ts	Activation state: active flag, draw mode (sessionStorage-persisted), layer selection, auto-select
src/hooks/useLassoResults.ts	Results state: selected features, polygon, geo-coordinate anchor
src/hooks/useLassoSelection.ts	Composition hook combining activation + results with Escape key handling
src/hooks/useClickOutside.ts	Generic click-outside hook used by MapControls and LassoResultsBar
src/utils/lassoSelection.ts	Spatial filtering (filterFeaturesInLasso with unkink + sync/async batching), buildLassoResult, handleLassoPolygonComplete, projectAnchorToScreen, normalizeCategoryKey
src/utils/lassoExport.ts	exportToCSV / exportToExcel (lazy-loaded xlsx) with allowlisted columns and formula injection protection

Modified Source Files

File	Description
src/DeckGLContainer.tsx	Integrates lasso layers, disables drag only while actively drawing, adds highlight layer for selected features, dims unselected layers
src/GeoSetMultiMap/Multi.tsx	Wires useLassoSelection hook, passes lasso props to MapControls/DeckGLContainer/LassoResultsBar, computes export column allowlist per layer, uses live viewport for anchor projection
src/layers/GeoSetLayer/GeoSetLayer.tsx	Same lasso integration for single-layer map view
src/components/MapControls.tsx	Adds lasso toggle button with dropdown, imports types from shared types.ts
src/GeoSetMultiMap/multiUtils.ts	Adds lassoSelectable field to normalized deck slice config
src/transformProps.ts	Builds exportColumnNames allowlist from Hover Data + Feature Info columns
src/types.ts	Adds shared LassoDrawMode and LassoLayer type definitions
src/declarations.d.ts	Type declarations for turf packages and @deck.gl-community/editable-layers
DeckSlicesControl/index.tsx	Adds lassoSelectable toggle checkbox to the admin slice configuration panel
package.json	Adds @turf/area, @turf/boolean-intersects, @turf/boolean-point-in-polygon, @turf/centroid, @turf/helpers, @turf/intersect, @turf/unkink-polygon, @deck.gl-community/editable-layers

New Test Files

File	Tests
test/components/LassoDropdown.test.tsx	13 tests — layer radio selection, ARIA attributes, draw mode toggles, shape sub-buttons
test/components/LassoResultsBar.test.tsx	14 tests — count display, export menu, CSV/Excel calls with allowlist, toast notifications, anchor positioning
test/components/useLassoLayer.test.ts	11 tests — layer creation, polygon completion callback, draw mode configs, completed polygon layers
test/components/MapControls.test.tsx	14 tests — toolbar buttons, lasso dropdown integration, layer selection
test/hooks/useLassoActivation.test.ts	10 tests — activation, deactivation, reset, auto-select, sessionStorage persistence
test/hooks/useLassoResults.test.ts	4 tests — initial state, polygon complete, clear selection, stale closure
test/hooks/useLassoSelection.test.ts	12 tests — composed behavior, escape key, toggle, layer selection
test/utils/lassoSelection.test.ts	16 tests — all geometry types, self-intersecting polygon, line-through-lasso, sync threshold, edge cases
test/utils/lassoExport.test.ts	15 tests — escapeCSV, sanitizeExcelValue, featuresToRows with allowlist
test/GeoSetMultiMap/multiUtils.test.ts	Added lassoSelectable normalization test

Documentation

File	Description
wiki/GeoSet-Map-Layer.md	Adds full "Lasso Select Tool" section with usage guide, selection behavior table, export details
wiki/GeoSet-Multi-Map.md	Adds lasso section with multi-layer specifics, links to main docs
wiki/Development-Guide.md	Adds lasso component entries to key utilities table, notes export allowlist
wiki/Home.md	Updates feature list
README.md	Minor update

Test Plan

• Manual: Freehand draw — Activate lasso, draw a freehand polygon around point features, verify correct features are selected and count is displayed
• Manual: Polygon draw — Switch to point-to-point mode, click vertices to form a polygon, verify selection
• Manual: Circle/Rectangle — Switch to circle and rectangle modes, drag to draw, verify selection
• Manual: Multi-layer — On a multi-layer map, verify the layer picker dropdown appears and targets the correct layer
• Manual: Export CSV — Select features, open export menu, click CSV, verify file downloads with correct data columns (Hover Data + Feature Info only)
• Manual: Export Excel — Same for Excel export, verify formula characters are prefixed with '
• Manual: Pan/zoom after selection — Draw a lasso, then pan/zoom the map, verify the results bar follows the polygon and map is pannable
• Manual: Draw mode persistence — Select rectangle mode, toggle lasso off and on, verify rectangle is still selected
• Manual: Escape key — While drawing or after selection, press Escape, verify lasso deactivates
• Manual: lassoSelectable toggle — In the Explore panel, uncheck lassoSelectable for a layer, verify it doesn't appear in the lasso layer picker
• Manual: Toast notifications — Verify success/error toasts appear for CSV and Excel exports
• Automated — 108 lasso-specific tests passing across 8 test suites

🤖 Generated with Claude Code

[jmeegan2]

Empty selection leaves you stuck

Drawing a shape that selects 0 features gives no results bar to dismiss and no way to redraw — have to toggle lasso off and back on. Should auto-reset to draw mode on 0 results or show a "0 selected" bar that can be cleared, this may be expected behavior but seems annoying.

Can't pan after selection

Test plan says "pan/zoom after selection, verify results bar follows polygon" — but dragPan: false stays active the whole time lasso is on, so panning (click-and-drag) is blocked even after drawing completes. Scroll-zoom works fine and the results bar tracks correctly when zooming. May not be an issue

Export includes internal fields

CSV/Excel export leaks internal property keys (fillColor, strokeColor, geojson, legendName) into the output. fillColor is null/empty in excel seemingly but not csv. Could clean up column filtering in a follow-up — not necessarily a blocker for this PR.
csv-xlsx-export.pdf

Results bar is cut off

[lhawkman27]

@jmeegan2 I made updates to fix those issues you found. I addressed each one.

[jmeegan2]

Export includes styling columns

Some styling columns are still leaking into the export (e.g. color_max_gust_mph). Currently
only Additional Details and Hover-Over Data columns should appear alongside _geometry_type,
_longitude, _latitude.

Suggestion: Rather than maintaining a blocklist of internal keys to exclude, switch to an
allowlist approach — only include the columns the user explicitly configured (Additional
Details + Hover-Over Data) plus the three geo columns. This is more maintainable since any new
styling/computed properties would be excluded by default.

[lhawkman27]

[lhawkman27]

Add lasso area size ti items selected panel

[jmeegan2]

looks good, good job