| track_query {traipse} | R Documentation |
Query track data for arbitrary locations
Description
Latent positions may be queried using arbitrary date-time values. The only method (for now) is 'linear', but default should be 'geodesic'. In time we include more methods to match the GeoPandas implementation.
Usage
track_query(x, y, date = NULL, query, type = "linear")
Arguments
x |
longitude |
y |
latitude |
date |
date-time in POSIXct (or can be ignore, for relative index-time) |
query |
required argument, date-time values to return inferred x, y positions for |
type |
linear, geodesic, rhumb, forward, backward, nearest (also need open/closed intervals) |
Details
If date is not included, time itself is treated as the obvious index on n-locations so
simple relative time, and query is expected to match this.
We use group_modify to keep the id groups:
trips0 %>% group_by(id) %>% group_modify(~track_query(.x$x, .x$y, query = c(4.5, 6.7)))
Value
data frame of 'x,y,date' of inferred positions
Examples
track_query(trips0$x[1:10], trips0$y[1:10], query = c(4.5, 5.5, 6.5))
track_query(trips0$x[1:10], trips0$y[1:10], trips0$date[1:10], query = trips0$date[1:10] + 10)
s <- seq(min(trips0$date), max(trips0$date), by = "1 hour")