Update README.md

Author: fkeck

README.md

@@ -17,19 +17,21 @@ First, load the package and the cholera dataset.
 
 The package provides a collection of simple `*Map` functions to easily get interactive maps.
 
-For example, you can use `quickMap` to quickly represent points and polygons and set colors and sizes using a column of the dataframe linked to the `sp` object.
+#### quickMap
+You can use `quickMap` to quickly represent points and polygons and set colors and sizes using a column of the dataframe linked to the `sp` object.
 
     quickMap(cholera$deaths, col.by="Count", size.by="Count")
 
 ![quickmap](https://cloud.githubusercontent.com/assets/9269625/7374091/9fc6c160-edd0-11e4-8d42-5cdf01face3e.png)
 
-
+#### heatMap
 You can use the `heatMap` function to get an heat map (raster image and/or contour lines) from a `SpatialGridDataFrame`.
 
     heatMap(cholera$deaths.den)
 
 ![heatmap](https://cloud.githubusercontent.com/assets/9269625/7374266/81d155a2-edd1-11e4-846e-6a2a12c80de7.png)
 
+#### netMap
 You can use `netMap` to map spatial networks from an `igraph` object. For example we can create a network of pumps in Snow's London by connecting pumps which are geographically close. Note that you need to set explicitly geographical coordinates to the graph vertices with the `lat` and `lon` attributes.
 
     pump.adj <- as.matrix(dist(coordinates(cholera$pumps)))