Women in Data Meetup, February 2014 The talk introduces a visualisation grammar called spruce-leaf. Spruce-leaf is a declarative format for creating interactive leaflet maps. The talk is aimed at developers and non-developers alike - no programming knowledge is necessary. With spruce-leaf you can describe the visualisation in JSON format: merge your shapefile (e.g. map of CCG areas in the UK) with CSV data, colour the features, add legend and hover-on information box.

1. Visualising data on
interactive maps
Anna Pawlicka
Data Engineer

2. A picture is worth 1000 words

3. A picture is worth 1000 words

4. Leaflet.js
• Open-source Java-Script library
• Mobile phone friendly
• Interactive

5. Spruce-leaf
• Visualisation grammar for choropleth maps
• Uses JSON format to describe data and map
• Joins geography with your data
• Colours the areas according to some values in your data
• Adds legend and info box

6. Data
• You will need:
• Geometry: TopoJSON file
• Data to map: CSV file
• Both need a common identifier

7. Colours
• Things to consider:
• Number of data classes
• Nature of your data: sequential, diverging, qualitative
• Perfect tool for all that: ColorBrewer

8. Specification

9. Example

10. Links
• Spruce-leaf grammar: https://github.com/MastodonC/spruce-leaf
• Spruce-leaf examples: https://github.com/MastodonC/spruce-leaf-examples
• ColorBrewer: http://colorbrewer2.org/
• Geographies:
• http://www.ordnancesurvey.co.uk/
• http://geocommons.com/
• https://github.com/samuelleach/uk-atlas