MapathonQA – JOSM Plugin

Post-mapathon data quality checker. The goal of this plugin is to give a quick, rough overview of the data quality output after a mapathon and create a report that can be shared with mapathon organisers/trainers so they are aware which issues they should highlight next time during training.

"Run QA on Current Layer" detects only objects created/modified during the mapathon's time window, as defined in "Run Full QA Check". The Individual Checks submenu detects all objects.

Workflow

1. MapathonQA → Run Full QA Check...
   • Step 1 – Project & Time Window: enter the mapathon name (optional), the HOT Tasking Manager project ID and the mapathon's UTC time window (defaults to the last 2 hours). Optionally tick "Include this report in MapathonQA_history.csv" to log the results in an Excel file for future tracking and comparing with later mapathons.
   • Click Find Mapathon Tasks →. The plugin queries the HOT TM API for all tasks touched in that time window and builds a JOSM search query matching them.
   • Step 2 – Load & Select Tasks: Click "Copy Search Query to Clipboard".
2. Load the task grid into JOSM — happens automatically on Close & Continue if you leave the checkbox ticked.
3. Edit → Search (Ctrl+F), paste the copied search query to select the tasks touched during the mapathon's time window
4. Download OSM data for the selected tasks using File → Download Along...
5. MapathonQA → Run QA on Current Layer — runs the 7 checks against the downloaded data, restricted to the mapathon's time window. Flagged objects are selected in the editor, an HTML report is generated, and (if enabled in Step 1) a row is appended to the history CSV file.
6. Review the flagged selection in JOSM, and share the HTML report with organisers/trainers.

Other entry points from the menu:

• Generate Demo Report — produces a sample HTML report with simulated issue counts, for previewing the report format without running it against real data.
• Set Report Save Folder... — choose where reports and the history CSV are saved; if unset, falls back to your Downloads folder, then Desktop, then the home folder.
• Individual Checks submenu — run any of the 7 report checks standalone against the whole current layer with no time filter
• 3rdPass Checks (Not in Report) submenu — extra checks for HOT TM Third Pass Validation; not part of the QA report.

Credits

The non-orthogonal building check (CheckNonOrthogonalBuildingsAction.java) ports the classification logic from Mapathoner's Helper.that_building() — same thresholds, same branch structure — reimplemented here using JOSM's own Way.getAngles(). Mapathoner is by qeef: https://mapathoner.mapathon.cz/

This plugin was built with the help of Claude, Anthropic's AI chatbot, used throughout for design, implementation, and debugging.

Menu structure

MapathonQA
├── Run Full QA Check...
├── Run QA on Current Layer
├── ───────────────
├── Generate Demo Report
├── Set Report Save Folder...
├── ───────────────
├── Individual Checks ▸
│   ├── Select Non-yes Building Tags
│   ├── Select Overlapping Buildings
│   ├── Select Buildings on Highways
│   ├── Select Non-orthogonal Buildings
│   ├── Select Buildings with Layer Tag
│   ├── Select Buildings with Shared Nodes
│   └── Select Untagged Objects
└── 3rdPass Checks (Not in Report) ▸
    ├── Select Highway Classification Mismatch
    ├── Select Residential With Multiple Place Nodes
    └── Select Residential Without Highway

All items in both submenus run with no time filter, independent of the full QA Check/report.

Architecture

File	Purpose
MapathonQAPlugin.java	Entry point, builds menu (see Menu structure below)
RunFullQAAction.java	Wizard: HOT TM API → task IDs → JOSM search query
RunQAOnCurrentLayerAction.java	Runs all 7 checks with progress dialog, generates report
GenerateDemoReportAction.java	Demo report with realistic simulated issue counts across all 7 checks
SetReportFolderAction.java	Lets the user override where HTML reports are saved (JOSM preference mapathonqa.reportDir)
HistoryLogger.java	Appends one row per real QA run to a persistent MapathonQA_history.csv for tracking quality trends over time — opt-in, off by default
CheckNonYesBuildingTagsAction.java	Check 1: building ≠ yes (menu: "Select Non-yes Building Tags")
CheckOverlappingBuildingsAction.java	Check 2: overlapping/contained buildings (matches JOSM's own built-in validator classification — see below), including exact-duplicate ways (GeometryUtil.isExactDuplicate) (menu: "Select Overlapping Buildings")
CheckBuildingsOnHighwaysAction.java	Check 3: buildings crossing roads, excluding building=roof (menu: "Select Buildings on Highways")
CheckNonOrthogonalBuildingsAction.java	Check 4: non-square corners (ported from Mapathoner's Helper.that_building(), see Credits) (menu: "Select Non-orthogonal Buildings")
CheckBuildingLayerTagAction.java	Check 5: buildings with layer=* tag (menu: "Select Buildings with Layer Tag")
CheckBuildingsWithSharedNodesAction.java	Check 6: shared nodes between buildings and other objects (menu: "Select Buildings with Shared Nodes")
CheckUntaggedWaysAction.java	Check 7: untagged objects — ways, plus standalone untagged nodes not used as a way vertex (multipolygon members excluded) (menu: "Select Untagged Objects")
GeometryUtil.java	Ray-casting, segment intersection, exact-duplicate detection, time filter, building-overlap classification via JOSM's own Geometry.polygonIntersection
ResidentialArea.java	Collects landuse=residential areas (closed ways + multipolygon relations, outer/blank-role members stitched into rings; holes ignored) — shared by the two residential checks below
SelectResidentialWithoutHighwayAction.java	Ported from 3rdPassMM: residential areas with no highway way touching/crossing them
SelectResidentialWithMultiplePlaceNodesAction.java	Ported from 3rdPassMM: residential areas containing more than one place=* node
SelectHighwayClassificationMismatchAction.java	Ported from 3rdPassMM: a highway way whose two endpoints each connect end-to-end to a different, but mutually consistent, highway= class (e.g. path–unclassified–path)
QAResults.java	Data container for all check results
ReportWriter.java	Generates branded HTML report (MM logo embedded as base64 SVG)

HOT TM API

GET https://tasking-manager-production-api.hotosm.org/api/v2/projects/{ID}/activities/latest/

Returns latest action per task. Plugin filters by actionDate within the time window. All taskStatus values included (MAPPED, VALIDATED, INVALIDATED, BADIMAGERY, READY).