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Zero to Map · Session 1 · ~75 minutes

Your first map.

By the end of this session you will have installed industry-grade GIS software, loaded two real DC datasets, styled them, and exported a finished map — which goes straight on the Map Wall with your name on it.

Before you arrive (10 min)

Put both files in a folder you can find, e.g. Documents/spl-workshop-1/.

Part 1 — Load the data (10 min)

Open QGIS → Project → New. Then drag wards.geojson from your file browser anywhere onto the QGIS window. A map of DC appears. Drag metro-stations.geojson in the same way.

Look at the Layers panel (bottom-left). Two entries — this is the core idea of GIS: your map is a stack of layers. Drag metro-stations above wards if it isn't already (points draw on top of polygons).

Right-click the wards layer → Open Attribute Table. Every shape on the map is also a row of data. Close it. That table is what makes this a information system and not a drawing.

Part 2 — Style the wards (15 min)

Double-click the wards layer → Symbology (left sidebar of the dialog).

At the top, change Single Symbol to Categorized. Set Value to name, pick a color ramp you like, press Classify, then OK. Eight wards, eight colors.

Too loud? Reopen Symbology, click the Symbol above the classes list, and drop Opacity to ~50%. Subtle beats saturated.

Part 3 — Style the stations + labels (15 min)

Double-click metro-stations → Symbology. Make the marker a white circle, size 2.5–3 mm, with a dark outline (Stroke color). Instant transit map.

Now labels: with the same dialog open, switch to Labels (left sidebar) → change No Labels to Single Labels, set Value to name, font size ~8, and under Buffer tick Draw text buffer (white, 0.7 mm). Press OK. If it's cluttered, that's normal — labels are a craft; keep them or turn them off, your call.

Part 4 — Export your map (15 min)

Project → New Print Layout, name it anything, OK. In the layout window: Add Item → Add Map, then drag a rectangle across the page. Your styled map appears.

Add a title: Add Item → Add Label, drag a box, type a real title (“Metro Stations by Ward” beats “my map”), bump the font in Item Properties. Add another small label with your name and “Data: DC Open Data” — cartographers always sign and cite.

Layout → Export as Image… → save as PNG. Done. That's a map you made.

The trophy

Post it on the Map Wall — the how-to is in ADDING-YOUR-WORK, and any officer will walk you through the pull request. Attend → make → publish, all in one session.

When something breaks (it will — it's fine)

macOS: “QGIS can't be opened” Right-click the app → Open → Open. (Gatekeeper distrusts apps from outside the App Store; QGIS is safe and signed.)
Windows: SmartScreen warning Click “More info” → “Run anyway.” Same story as macOS.
A CRS / “transformation” popup appeared Accept the default and move on. It's asking how to flatten the round Earth; the default is right for us. (CRS = coordinate reference system — Session 2 topic.)
The map is blank Right-click the layer → Zoom to Layer(s). You were probably just looking at the wrong part of the planet.
Panels disappeared View → Panels → tick Layers. Docked panels wander; this brings them home.
Download opened as text in the browser Go back and right-click the link → Save Link As…. GeoJSON is just text — browsers like to show it off.