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README.md

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+- What kind of data do you have?
+  - Points
+    - How much data?
+      - Just enough
+        - Convert the data to GeoJSON & make a simple Leaflet map
+      - Too much in a confusing way, but each point's data is important?
+        - Cluster your points with Leaflet.markercluster
+      - Too much and the points have some value that can be aggregated
+        - Create hexbins of your points with the QGIS hexbin plugin, to make
+          polygons. Start again at Polygons
+      - Too much and the points just represent presence - like tweets
+        - Create a heatmap with Leaflet.heat or QGIS heatmap plugin. If you
+          use QGIS heatmap, start again at Raster.
+  - Polygons
+    - How much data?
+      - Just enough
+        - Convert the data to GeoJSON & make a simple Leaflet map
+      - Too much, the polygons have necessary detail
+        - Use TileMill to render an interactive map with UTFGrid
+      - Too much, the polygons have unnecessary details
+        - Simplify them with TopoJSON or QGIS
+    - What kind of attributes do they have?
+      - Absolute numbers
+        - Convert the points to centroids with QGIS and start from Points
+        - Normalize absolutes to rates by dividing over polygon area,
+          and start from Rates
+      - Rates or Categories
+        - Make a choropleth map with Leaflet for small data, TileMill
+          for big data
+  - Raster
+    - Render a map with TileMill and use the tiles in Leaflet
+  - Names of places, like countries
+    - With IDs, like ISO3 codes
+      - Download Natural Earth data at the right level, join with QGIS,
+        and start again at Polygons
+    - Without IDs
+      - Find data with IDs, or manually join with polygons
+  - Addresses
+    - You can't map addresses directly. Geocode them with OpenRefine or
+      Geo for Google Docs, and then start at Points
+  - A format that I can't read
+    - Install GDAL and use ogr2ogr to convert the file
+    - Ask your source for a better file format
+  - I don't have data yet
+    - Contact the town or federal GIS dept you need
+    - Use FOIAMachine.org to request data via FOIA
+
+- Visualization defaults
+  - Projection:
+    - If it's a web map with tiles, use Mercator
+    - If using d3 and not using tiles anywhere, use whatever fits best
+  - Colors:
+    - When in doubt, use ColorBrewer
+  - Scales:
+    - For any data
+      - Try linear first
+      - Then quantile
+    - For data of rates or compounding
+      - Try log and power scales
+  - Points:
+    - Start with normal circles with no strokes
+    - Scale points by area, not diameter