added some resources re openstreetmap as a base map

README.md

@@ -2,4 +2,15 @@
 
 Simple (and not so simple) examples of mapping data with R
 
-You might also like https://git.soton.ac.uk/twr1m15/la_emissions_viz which drives https://rushby.shinyapps.io/LAemissions/
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+You might also like https://git.soton.ac.uk/twr1m15/la_emissions_viz which drives https://rushby.shinyapps.io/LAemissions/
+
+## Resources
+
+### Openstreetmap for base maps (i.e. map tiles/rasters)
+
+ * [Edinburgh green space as an example](https://ourcodingclub.github.io/tutorials/spatial-vector-sf/)
+ * [Madrid supermarkets](https://dominicroye.github.io/en/2018/accessing-openstreetmap-data-with-r/)
+ 
+### Google maps for base maps
+
+They want you to have an API key now. Yeah nah.
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