feat(analysis): add Identity and Union overlay tools

GEOLIBRE_PARITY.md

@@ -166,8 +166,8 @@ _GeoLibre: docs/features.md › Attribute data and expressions; docs/arcgis-edit
 _GeoLibre: docs/features.md › Processing and analysis; docs/user-guide/processing.md,
 model-builder.md, segmentation.md, obia.md_
 
-- [ ] **Spatial join, intersect, union**. Partial: spatial join, clip, erase and intersect are
-  built in; union, identity and near are missing (_Roadmap: solid ground_).
+- [ ] **Spatial join, intersect, union**. Partial: spatial join, clip, erase, intersect, identity
+  and union are built in; near is missing (_Roadmap: solid ground_).
 - [ ] **More built-in vector tools**: attribute join, merge, extract vertices, points along lines,
   fix/check geometry, random extract, buffer options. Partial (_Roadmap: solid ground_).
 - [ ] **Routing services**: isochrones, service areas, OD matrix, multi-stop routing,

README.md

@@ -99,7 +99,7 @@ Every screenshot is RustGIS itself, rendered offscreen by `cargo run -p rustgis-
 | **Web tiles** | XYZ/TMS/WMS raster tiles, Mapbox Vector Tiles and MapLibre styles (sprites, patterns, expressions), cached and fetched in the background |
 | **Cartography** | Single symbol, unique values, graduated colours, proportional symbols; label classes with SQL queries, straight and curved line placement, installed font families, scale ranges and annotation; stacked and dashed line strokes, symbol levels, reference scales and polygons without fill; masking, display filters, aggregation bins, 2.5D extrusion; graphics and dynamic text |
 | **Editing** | Create, move, rotate, scale, merge, split and explode features; snapping, templates, elevation, traverse, topology rules; domains, subtypes, attribute rules, relationships, archiving; undo for everything |
-| **Analysis** | Selection by attributes (SQL) and location; Buffer, Clip, Erase, Intersect, Dissolve, Summarize Within, Summary Statistics, Spatial Join, Zonal Statistics, A5 grids and a geometry calculator; viewshed, line of sight, IDW, ordinary kriging, shortest path, suitability modelling; ModelBuilder on a node canvas and scripts with command, parameter and value completion; 1,000+ [GeoLibre](https://github.com/opengeos/geolibre-rust) and Whitebox raster, vector, LiDAR, hydrology and terrain tools |
+| **Analysis** | Selection by attributes (SQL) and location; Buffer, Clip, Erase, Intersect, Identity, Union, Dissolve, Summarize Within, Summary Statistics, Spatial Join, Zonal Statistics, A5 grids and a geometry calculator; viewshed, line of sight, IDW, ordinary kriging, shortest path, suitability modelling; ModelBuilder on a node canvas and scripts with command, parameter and value completion; 1,000+ [GeoLibre](https://github.com/opengeos/geolibre-rust) and Whitebox raster, vector, LiDAR, hydrology and terrain tools |
 | **Imagery** | Ortho and reality mapping, pixel classification (k-means, minimum distance, a trainable neural network), mensuration, hosted imagery tiles |
 | **Layouts and reports** | Page layouts with map frames, legends, scale bars, grids and map series; publication sheets and figures in one command, format panes, guides, snapping and element locks; reports with groups, statistics, charts and subreports; presentations (HTML slideshow, PDF); notebooks (Jupyter in and out) |
 | **Sharing** | PNG export at any DPI; PDF; web map pages, OGC API Features collections, MapLibre styles, glTF scenes, locators; project, map and mobile map packages; offline areas with sync |

ROADMAP.md

@@ -63,8 +63,7 @@ Correct, robust and recoverable, with the foundations other themes stand on.
   administrator can fix for a managed install (no AI Assistant, plugins or web services).
 - Extend the OS keychain secret store to service connections (database passwords, S3 keys,
   AI provider keys and the ChatGPT sign-in's tokens are already kept there).
-- Overlay tools beside Clip, Erase and Intersect: union, identity and near
-  ([#959](https://github.com/opengeos/RustGIS/issues/959)).
+- A Near tool beside the overlay tools ([#959](https://github.com/opengeos/RustGIS/issues/959)).
 - Spatial Join by distance, closest, centre in and largest overlap, with merge rules (sum, mean,
   first…) for one-to-one joins ([#851](https://github.com/opengeos/RustGIS/issues/851)).
 - Vector tools, each writing a new layer: join field (a one-off attribute join), merge (append
@@ -220,11 +219,11 @@ Open questions rather than plans; discuss before building.
   templates, elevation, topology; domains, subtypes, attribute rules, contingent values,
   relationships, archiving.
 - Analysis: selection by attributes and location; polygon, lasso and radius on the map; overlay
-  (clip, erase, intersect), proximity (buffer) and summary tools, spatial join, zonal statistics,
-  A5 grids, kriging and Calculate Geometry with metric or imperial units; guided workflows
-  (viewshed, line of sight, IDW, shortest path, suitability); ModelBuilder on a node canvas,
-  scripts with command, parameter and value completion, and history copied as code; the GeoLibre
-  and Whitebox suite (1,000+ tools) natively and in the browser.
+  (clip, erase, intersect, identity, union), proximity (buffer) and summary tools, spatial join,
+  zonal statistics, A5 grids, kriging and Calculate Geometry with metric or imperial units; guided
+  workflows (viewshed, line of sight, IDW, shortest path, suitability); ModelBuilder on a node
+  canvas, scripts with command, parameter and value completion, and history copied as code; the
+  GeoLibre and Whitebox suite (1,000+ tools) natively and in the browser.
 - Layouts (map frames, surrounds, map series, publication sheets and figures in one command,
   format panes, guides, snapping, element locking and PDF), reports, presentations and
   notebooks; the web app embeddable in a page (`?embed`).