1. Intro to GGMAP Emmalee Dolfi

2. Ethical Implications of Spatial Analysis  Spatially displaying data can change how it’s interpreted  Locational privacy and ethics  Volunteered Geographic Information System (VGIS)  Location-based services (LBS)  Data is often collected without the subject knowing it  Radio Frequency Identification (RFID)  Crime Mapping

3. What is GGMAP?  Spatial visualization with Google Maps, OpenStreetMaps, StamenMaps and CloudMadeMaps  Combine with GGPLOT2 to spatially display data  Use ggmap() to create basemap layer, use “+” to add ggplot2 layer with data HoustonMap <- qmap("houston", zoom = 13, color = "bw") HoustonMap + geom_point(data=violent_crimes,aes(x = lon, y = lat, colour = offense ) ) HoustonMap <- qmap("houston", zoom = 13, color = "bw") HoustonMap + geom_point(data=violent_crimes,aes(x = lon, y = lat, colour = offense ) )

4. Geocoding Your Data  Data must be spatially referenced in order to display it using ggmap

5. The Process of Geocoding  Assigning a location (latitude, longitude) to an address  Compares elements in the given address the reference data set and finds the best match

6. Getting a Base Map  Get_map() combines get_googlemap(), get_openstreetmap(), get_stamenmap(), get_cloudmademap()  Arguments:  Center, zoom, maptype, color, source

7. Examples of Maptypes

8. Displaying Point Data  Geom_point()  Must specify data  Argument: aes()  x = longitude  y = latitude  color = variable to display  If you have factored levels:  Can scale the points based on these factors

9. Hexagonal Bins  Displays a spatial histogram  Calculates density per bin from point data  Stat_binhex()  Specify data  Need lat and long in aes()  Bins controls the number of bins across the x-axis, which control the size of the bins  Alpha controls transparency

10. Kernel Density  Calculate magnitude per unit area from point data  Creates equal area cells (like a raster) and gives each cell a value based on the number of point in a “search radius”

11. References  Michael Mann, Department of Geography, GWU  http://cran.r-project.org/web/packages/ggplot2/ggplot2.pdf  http://cran.r-project.org/web/packages/ggmap/ggmap.pdf  (Movebank.org) Fuller, M.R., Seegar, W.S., and Schueck, L.S. 1998. Routes and Travel Rates of Migrating Peregrine Falcons Falco peregrinus and Swainson's Hawks Buteo swainsoni in the Western Hemisphere. Journal of Avian Biology 29:433-440.  http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=An_overview_of_ geocoding  http://www.cdc.gov/dhdsp/maps/gisx/training/module3/files/2_spatial_analyst_modul e.PDF