NEWS

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explodemap 0.2.0 (2026-05-27)

New features

• Added a three-level grouped layout engine via explode_grouped(), supporting "auto", "auto_collision", and "manual" anchor modes for multi-region and national-scale layouts.
• Added layout_regions() to compute region anchors as a standalone step for custom grouped-layout workflows.
• Added estimate_block_radii() to estimate per-region block radii using the 85th percentile of unit-to-centroid distances.
• Added export_topojson() for optional TopoJSON export via the external mapshaper CLI tool, for downstream tools such as Power BI.
• Added summary.grouped_exploded_map() for grouped-layout diagnostics, including local displacement parameters, anchor parameters, and block radii.
• Added optional bounded collision refinement to explode_sf() and explode_state() for dense municipal cores, with diagnostics stored in the returned refinement component.
• Added explode_section() for drill-down dashboards that explode one selected section while keeping the remaining geography as faded or hidden context for focus_map().

Improvements

• Centroid handling was refactored throughout the package to avoid sf attribute warnings during centroid calculations.
• compute_stats() now accepts centroid_fun so geometry statistics and displacement use the same centroid semantics.
• explode_sf() and explode_state() now respect partial manual overrides: users may set only alpha_r or only alpha_l while deriving the other parameter from geometry.
• Direction vectors and distance scaling now handle true zero-distance cases without suppressing sub-metre coordinate differences.
• Grouped anchor collision refinement is now deterministic for coincident anchors, improving reproducibility.
• Manual grouped anchors now validate that every region has one anchor and that regions are not duplicated in the anchor table.
• Grouped objects now inherit from both grouped_exploded_map and exploded_map, improving method consistency.
• Grouped S3 methods were consolidated and cleaned up for more consistent printing, plotting, and summary output.
• Distance formatting in diagnostic output now adapts between metres and kilometres, improving readability for both small synthetic examples and real-world datasets.
• Focus maps now support non-blocking info cards, selected-area sizing controls, and denser-layer performance tuning for Shiny workflows.
• Focus maps now support named group_palette values, allowing Shiny apps to align widget colouring with dashboard legends or domain-specific palettes.
• Focus maps now support context features via context_col, context_mode, context_opacity, and context_clickable, enabling selected-region focus maps with muted background geography.
• Focus maps now support adaptive tiny-feature focus controls via min_focus_width, min_focus_height, tiny_feature_threshold, and tiny_feature_boost, improving municipal drill-down maps with very small selected polygons.
• Focus maps now support selected-feature origin context via origin_context and origin_context_position, including an overview inset that keeps small municipal focus views anchored to the broader geography. The cue is opt-in by default.
• Focus maps now expose focus_context_opacity to tune how strongly the non-selected background geography recedes during focused views.
• Focus maps now support opt-in drag zoom via show_drag_zoom. Users can use the button or Shift-drag to draw a marquee rectangle and smoothly zoom into dense clusters before selecting individual features.
• Drag zoom behaves as a navigation layer over focus maps: plain clicks still focus polygons while the toggle is active, and turning the tool off no longer resets the current focus.
• explode_grouped() now accepts visual aliases (anchor_expand, anchor_buffer, density_scale, and block_sep) for the corresponding grouped-layout solver controls.
• Shiny workflows now have quieter geometry builders, automatic plot suppression safeguards, and selection events for linked side panels.
• Public-facing dashboard examples now show clear Shiny validation messages for failed boundary downloads, empty data, map-generation failures, and widget-rendering failures.
• TIGER/Line downloads and TopoJSON export now fail with clearer, actionable error messages when external services, files, or tools are unavailable.
• validate_input() now returns visibly, making repaired geometries less fragile in internal workflows.

Documentation

• Added three vignettes: getting started, grouped layouts, and paper replication.
• Added small installed examples for the basic sf workflow, optional collision refinement, lookup-table grouping, and manual parameter tuning.
• Added a workflow-selection vignette for release-oriented user guidance.
• Added Shiny-oriented guidance for exploding a visible section while preserving the rest of the map as context in focus_map().
• Added an inst/CITATION entry for academic citation.
• Added pkgdown site configuration and GitHub Pages support.

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explodemap 0.1.0

Initial release

• Added the core two-level displacement engine for exploded-view cartography of dense administrative boundary data.
• Added three public entry points: explode_sf(), explode_sf_with_lookup(), and explode_state().
• Added analytical parameter derivation via derive_params(), implementing Analytical Results 1 and 2.
• Added geometry statistics via compute_stats().
• Added the exploded_map S3 class with print(), plot(), and summary() methods.
• Added calibration_row() for cross-dataset calibration tables.
• Added TIGER/Line download and caching support via explode_state().
• Added a state registry with New Jersey, Pennsylvania, Ohio, and New York configurations.
• Added example workflows for cross-state calibration, Canada validation, and HHS grouped layouts.