Times

One of the most powerful features of Targomo is the ability to quickly get A-to-B travel times for a multitude of source/target combinations. These make for great ‘heatmap’ visuals, or can be used for further analysis and aggregation.

Getting the Data

For the time service, getTargomoTimes() returns a Simple Feature Collection of 4 fields. Each feature is a POINT (corresponding to the target point), and the fields are:

• sourceId, targetId - given IDs for the points, or inferred numeric IDs if none supplied
• travelType - the travel mode (can supply multiple as with routes)
• travelTime - the time taken in seconds to get from the source to the target

# load package
library(TargomoR)

# set source and target data
source <- data.frame(id = "Big Ben", lat = 51.5007, lng = -0.1246)
target <- data.frame(id = c("Tower Bridge", "Covent Garden"),
                     lat = c(51.5055, 51.5117),
                     lng = c(-0.0754, -0.1246))

# query the API
times <- getTargomoTimes(source_data = source, target_data = target,
                         source_lat = ~lat, source_lng = ~lng,
                         target_lat = ~lat, target_lng = ~lng,
                         source_id = ~id, target_id = ~id,
                         options = targomoOptions(travelType = "car"))

# examine the output
times
#> Simple feature collection with 2 features and 4 fields
#> geometry type:  POINT
#> dimension:      XY
#> bbox:           xmin: -0.1246 ymin: 51.5055 xmax: -0.0754 ymax: 51.5117
#> epsg (SRID):    4326
#> proj4string:    +proj=longlat +datum=WGS84 +no_defs
#> # A tibble: 2 x 5
#>   sourceId targetId      travelType travelTime          geometry
#>   <chr>    <chr>         <chr>           <int>       <POINT [°]>
#> 1 Big Ben  Covent Garden car               370 (-0.1246 51.5117)
#> 2 Big Ben  Tower Bridge  car               753 (-0.0754 51.5055)

Integration with Leaflet

As with the polygon and route services, there are three ways to add time data to a map:

• use drawTargomoTimes() to send your times dataset to the map
• use addTargomoTimes() to combine the API call and drawing in one
• write your own drawing function using leaflet::addMarkers or leaflet::addCircleMarkers

In the example below, we’ll generate some random points and use addTargomoTimes() to combine requesting the data and adding it to the map:

# get random target data (source data = Big Ben as before)
targets <- data.frame(id = 1:100,
                      lat = runif(100, min = 51.45, max = 51.55),
                      lng = runif(100, min = -0.17, max = -0.07))

leaflet() %>% 
  addTargomoTiles() %>% 
  addTargomoTimes(source_data = source, source_id = ~id,
                  target_data = targets, target_id = ~id,
                  options = targomoOptions(travelType = "bike"))
#> Assuming "lng" and "lat" are longitude and latitude, respectively
#> Assuming "lng" and "lat" are longitude and latitude, respectively

Drawing Options

Using addTargomoTimes() or drawTargomoTimes() you can customise the way the routes appear on the map with a call to timeDrawOptions() and timeLegendOptions(). The options available are:

timeDrawOptions

Option	Default	Meaning
palette	"viridis"	A colour palette name e.g. “Blues”, “viridis”
type	"numeric"	“numeric” or “bin” - continuous or discrete groupings
maxTime	1800	Maximum time to allow for (in seconds)
reverse	FALSE	Reverse the colour palette?
bins	c(600, 1800)	A number of bins or vector of cut points (only for “bin” type)
legend	TRUE	Add a legend to the map
legendOptions	timeLegendOptions()	A list of legend options - see below
radius	10	Radius of the circle markers used
stroke	TRUE	Whether to draw the marker border
weight	3	Stroke weight in pixels
color	"black"	Stroke colour
opacity	0.5	Stroke opacity
fill	TRUE	Fill the markers with colour (from palette)?
fillOpacity	0.5	Fill opacity

timeLegendOptions

Option	Default	Meaning
position	"topright"	Legend position on map
title	"Travel Times"	Legend title
layerId	NULL	Leaflet layer id for legend

Changing some of these options, we could re-draw the above map with smaller markers, using the inferno palette and white borders, with a different legend title and discrete bins:

leaflet() %>% 
  addTargomoTiles() %>% 
  addTargomoTimes(source_data = source, target_data = targets,
                  options = targomoOptions(travelType = "bike"),
                  drawOptions = timeDrawOptions(
                    palette = "inferno",
                    type = "bin", bins = c(0, 300, 600, 900, 1200, 1800),
                    color = "white", radius = 5,
                    opacity = 1, fillOpacity = 1,
                    legendOptions = timeLegendOptions(
                      position = "bottomleft",
                      title = "Cycling Times"
                    )
                  )
  )
#> Assuming "lng" and "lat" are longitude and latitude, respectively
#> Assuming "lng" and "lat" are longitude and latitude, respectively