A Map with a Narrower View

We can limit users' ability to pan away from the map's focus using the options argument in the leaflet() function. By setting minZoom anddragging, we can create an interactive web map that will always be focused on a specific area.

leaflet(options = 
        leafletOptions(minZoom = 14, dragging = FALSE))  %>% 
  addProviderTiles("CartoDB")  %>% 
  setView(lng = -73.98575, lat = 40.74856, zoom = 14)

Alternatively, if we want our users to be able to drag the map while ensuring that they do not stray too far, we can set the maps maximum boundaries by specifying two diagonal corners of a rectangle.

You'll use dc_hq to create a map with the "CartoDB" provider tile that is centered on DataCamp's Belgium office.

Cet exercice fait partie du cours

Interactive Maps with leaflet in R

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Instructions

Use a minimum zoom level of 12.
Set the dragging option to TRUE.
Use maximum bounds of .05 decimal degrees from the headquarters.

Exercice interactif pratique

Essayez cet exercice en complétant cet exemple de code.

leaflet(options = leafletOptions(
                    # Set minZoom and dragging 
                    minZoom = ___, dragging = FALSE))  %>% 
  addProviderTiles("CartoDB")  %>% 
  
  # Set default zoom level 
  setView(lng = dc_hq$lon[2], lat = dc_hq$lat[2], zoom = 14) %>% 
  
  # Set max bounds of map 
  setMaxBounds(lng1 = dc_hq$lon[2] + ___, 
               lat1 = dc_hq$lat[2] + .05, 
               lng2 = dc_hq$lon[2] - ___, 
               lat2 = dc_hq$lat[2] - .05)

Modifier et exécuter le code

Interactive Maps with leaflet in R

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Chapter 1 will introduce students to the htmlwidgets package and the leaflet package. Following this introduction, students will build their first interactive web map using leaflet. Through the process of creating this first map students will be introduced to many of the core features of the leaflet package, including adding different map tiles, setting the center point and zoom level, plotting single points based on latitude and longitude coordinates, and storing leaflet maps as objects. Chapter 1 will conclude with students geocoding DataCamp’s headquarters, and creating a leaflet map that plots the headquarters and displays a popup describing the location.

Exercise 1: Introduction to leaflet Exercise 2: Loading the leaflet Library Exercise 3: Creating an Interactive Web Map Exercise 4: Map Tiles Exercise 5: Provider Tiles Exercise 6: Adding a Custom Map Tile Exercise 7: Setting the Default Map View Exercise 8: A Map with a View I Exercise 9: A Map with a Narrower View

Exercice en cours

Exercise 10: Plotting DataCamp HQ Exercise 11: Mark it Exercise 12: Adding Popups and Storing your Map

In Chapter 4 students will learn to map polygons, which can be used to define geographic regions (e.g., zip codes, states, countries, etc.). Chapter 4 will start by plotting the zip codes in North Carolina that fall in the top quartile of mean family incomes. Students will learn to customize the polygons with color palettes and labels. Chapter 4 will conclude with adding a new layer to the map of every college in America that displays every zip code with a mean income of $200,000 or more during the 2015 tax year. Through the process of mapping zip codes students will learn about spatial data generally, geoJSON data, the @ symbol, and the addPolygons() function. Furthermore, students will have an opportunity to practice applying many of the options that they learned about in the previous chapters, such as popups and labels, as well as new ways to customize their maps, such as the highlight option in addPolygons().

Exercise 1: Spatial Data Exercise 2: Introduction to Spatial Data Exercise 3: Exploring Spatial Data Exercise 4: Joining Spatial Data Exercise 5: Mapping Polygons Exercise 6: addPolygons() Function Exercise 7: NC High Income Zips Exercise 8: addPolygon() Options Exercise 9: Let's do some Logging Exercise 10: Putting it All Together Exercise 11: Wealthiest Zip Codes in America Exercise 12: Final Map Exercise 13: Thank you!