Feature suggestion: track and output secondary variables in ttm and attm

[HarryRobertsITS]

A useful feature for the travel_time_matrix() and arrival_travel_time_matrix() functions (and perhaps others which I don't use) would be to keep track of secondary variables and provide them as an additional output in the data table.

In particular it would be useful to know the following for each o-d pair:

• total distance
• total fare
• time spent using each mode and waiting
• no. of transfers
• gross elevation gain (i.e. amount of uphill - ideally by mode)
• gross elevation loss (i.e. amount of downhill - ideally by mode)

(I know that distance is an output of detailed_itineraries(), but it would be useful to have it as an output of the faster functions)

My (limited) knowledge of graph theory leads me to believe that it would be theoretically possible to do this without increasing complexity, and it would greatly increase the usefulness of the package and underlying software to economists and statisticians with an interest in obtaining explanatory variables for modelling travel choices.

Is this achievable in r5r with the existing features of R5, or is this something I should take upstream?

[BardyBard]

Hi @HarryRobertsITS,

time spent using each mode and no. of transfers is already reported by expanded_travel_time_matrix() which uses the same process as travel_time_matrix() under the hood.

As for the two elevation questions, I am fairly certain that this would not be possible to extract from existing R5 processes. If you are interested in obtaining these variables you could calculate them from the path geometry which is returned by detailed_itineraries().

As for total distance and total fare perhaps these are possible and we are looking at the possibility of it's implementation in #464. But it is a low priority issue since the possibility already exists in detailed_itineraries().