A step-by-step series for the analysis graph — the dataflow language that answers questions about the GIS explorer's Earth data ("is sea temperature correlated with wind?", "how fast is the ocean warming?"). The tutorials focus on the graph editor, the visual front end where you build and edit analysis programs node by node.
These tutorials are the guided path; the Analysis module guide is the reference — every node type, param, and statistical convention is documented there. The story of the explorer sample itself is in the book deep-dive Geo GIS Explorer.
Setup. Everything runs inside Earth Explorer, the standalone open source explorer built on this engine: clone it,
npm run dev, and click the ⚗ Analysis button in the top bar. No build steps, no API keys (only tutorial 5's Ask tab wants one), and the data streams from public NOAA/NASA feeds — nothing to install.
The path#
| # | Tutorial | You'll learn |
|---|---|---|
| 1 | Your First Graph | The editor itself: right-click to add nodes, drag ports to connect, set params, run, read the map + answer, share a link. Builds a "how fast is the ocean warming" trend map. |
| 2 | Correlation Maps | Temporal vs spatial correlation — the same formula asking two different questions. Builds SST × wind, flips it to a single spatial number, and reads both honestly. |
| 3 | El Niño Composites | Branching graphs: filter one stack two ways by ENSO phase, average each branch, subtract. The classic ENSO dipole from first principles. |
| 4 | Series, Charts & Lag | From maps to time series: regions, areaMean, the chart sink, and correlateSeries with lags — does ENSO lead global ocean warmth? |
| 5 | Ask, Then Edit | The AI front end: let Claude write the program, inspect it in the Graph tab, tweak it yourself, and keep the conversation in sync. |
Each tutorial ends with the finished program as JSON — compare against yours, or use it to recover if you get lost (the Graph tab's built-in dropdown also carries finished versions of several of these).
Cheat sheet#
- Right-click empty canvas → add a node (grouped by sources / transform / reduce / combine / sinks). Right-click a node → delete / disconnect.
- Drag an output dot (right edge) onto an input dot (left edge) to connect. Ports that would reject the connection dim while you drag.
- Drag empty canvas (or middle-mouse anywhere) to pan, wheel to zoom, ⟲ to reset the view.
- Click an input dot or an edge to disconnect it.
- Port colors are the value types: stack blue, field lavender, series teal, scalar amber, region green.
- Red-bordered nodes have validation errors — hover for the message; the line above the canvas shows the first few.
- ▶ Run executes; results appear below the panel and (for
displaysinks) on the map itself. Pick any layer or view in the top bar to hand the map back. - 🔗 Copy link produces a URL that reopens and reruns the exact program
(
?prog=); 💾 saves it as a named preset in the browser.