Sawgraph Explorer

A web-based interface for querying the SAWGraph knowledge graph — a PFAS contamination dataset linking water samples, industrial facilities, and hydrological features across the United States.

What it does

The app lets you ask spatial analysis questions in plain English:

"What water samples are downstream of [22 - Utilities] facilities in Ohio?"

It translates those questions into multi-step SPARQL pipelines, executes them against SAWGraph's knowledge graph endpoints, and renders the results on an interactive map.

Stack

• React 19 + TypeScript + Vite 7
• Zustand — application state
• React Query — filter dropdown data with staleTime: Infinity
• react-leaflet — map rendering
• S2 Level 13 cells — spatial bucketing for all geo queries

Getting started

cd sawgraph-query-editor
npm install --legacy-peer-deps   # react-leaflet has a peer dep mismatch with React 19
npm run dev

Other commands:

npm run build    # TypeScript check + Vite build
npm run lint     # ESLint
npm run preview  # Preview production build

How queries work

An Analysis Question has three parts:

[Block A — target entity]  [Relationship]  [Block C — anchor entity]
     water samples            downstream       facilities in Ohio

When you click Apply, the query engine:

1. Plans the question (engine/planner.ts) → array of PipelineStep
2. Executes steps sequentially (engine/executor.ts), threading S2 cell sets between steps
3. Renders results as map layers (resultTransformer.ts → MapFeature[])

Supported entity types: samples, facilities, water bodies Supported relationships: near (~1–2 km), downstream, upstream

SPARQL endpoints

All hosted at frink.apps.renci.org:

Endpoint	Used for
sawgraph	Sample data, substances
fiokg	Facility industry codes
federation	Facility spatial queries (kwg-ont:sfContains)
spatialkg	S2 cell lookups, region/county boundaries
hydrologykg	Upstream/downstream tracing

Filter dropdowns

Dropdown	Data source
Industry (NAICS)	Live SPARQL → fiokg, fallback to hardcoded list
Substance	Live SPARQL → sawgraph, fallback to hardcoded list
Material type	Live SPARQL → sawgraph, fallback to hardcoded list
State	Static — all 50 states; 13 with SAWGraph data are selectable
County	Live SPARQL → spatialkg, fetched on state selection

Docs

Inside docs/:

File	Contents
ARCHITECTURE.md	System design, module boundaries, data flow
SCHEMA.md	Predicate inventories, class counts, endpoint roles
DEBUGGING.md	Documented bugs with root causes and fixes
CONVENTIONS.md	Coding standards, endpoint selection rules
changelog/	Weekly changelogs (YYYY-Www.md)
plans/	Feature planning: drafts/ → active/ → done/