This document discusses geographic data and the Leaflet.js JavaScript library for interactive maps. It provides examples of open source web mapping projects and tools for crowdsourcing and displaying spatial data. Leaflet.js is highlighted for its ease of use, support for mobile, performance, open source nature, and active developer community. The document demonstrates adding Chicago building footprint data to an interactive map built with Leaflet.js.

1. Geographic Data and Leaflet.js
Fall 2015 hack@uchicago Hackathon

2. Web mapping tools
democratize spatial
knowledge

3. WhereWeWalk
https://github.com/manleyjster/wherewewalk

6. LargeLots.com
http://largelots.org/
http://datamade.com/

8. MapKnitter
http://mapknitter.org/
https://github.com/publiclab/mapknitter

9. “Maps are often used by those in power to exert
influence over territory, or control territorial
narratives. "Grassroots mapping" attempts to
invert this dynamic by using maps as a mode of
communication and as evidence for an alternative,
community-owned definition of a territory.”
http://publiclab.org/wiki/balloon-mapping

12. iD Editor
https://www.openstreetmap.org/edit
https://github.com/openstreetmap/iD
https://www.mapbox.com/osmdev/

13. Other cool projects
⬝ http://mapmill.org/ - Crowdsourced aerial
image processing
⬝ http://www.geograph.org.uk/ - Aims to collect
geographically representative photos for every
km² in Britain and Ireland
⬝ http://hot.openstreetmap.org/ - OpenStreetMap
Humanitarian

14. In the wild today:
Leaflet*
mapbox.js*
Google Maps JavaScript API
ArcGIS API for JavaScript
OpenLayers*
d3*
mapbox-gl-js*

15. Challenges in web mapping
⬝ Creating and acquiring map tiles.
⬝ Getting data into the browser.
⬝ Rendering large vector data sets.

16. What’s cool about Leaflet?
⬝ Easy to add custom map tiles and data sets
⬝ Supports mobile devices
⬝ Fast!
⬝ Open source
⬝ Good maintainers and active development
community

17. Useful tools for geospatial analysis
⬝ GDAL (Geospatial Data Abstraction Library)
⬝ includes command line tool ogr2ogr, useful for
converting between vector formats.
⬝ QGIS
⬝ Full-featured GIS software with GUI

18. Try it out
Chicago Data Portal - Building Footprints Data Set
http://bit.ly/1Bsoyaf
1 git clone https://github.com/manleyjster/gentrifoo
2 cd gentrifoo
3 npm install
4 git checkout -b <your-name>
5 npm start

19. + + +
Building footprints
Bin building stories
by census tract
Bin building construction
year by census tract

20. Add something
1. Add a panel to the map to show additional data from the GeoJSON file
when the user hovers over a census tract.
2. Add a slider so that the user can advance time forwards and backwards.
3. Improve the property deterioration model - make the condition of
properties in each census tract depend on the conditions in neighboring
census tracts. (Make use of the spatial indexing of the RTree that is built
in to the GentrificationModel).
http://leafletjs.com/reference.html

21. justinmanley.io
@outoftheyards
Justin Manley
manleyjster@gmail.com