The goal of tvmeasures is to aid ARC staff and their consultants in generating project evaluation reports for transit projects under the Concept 3 / Transit Vision program. It contains functions and libraries to post-process outputs from the third-party tools Remix and Conveyal, along with ARC’s own GIS-based cultural and environmental sensitivity calculator.
You can install tvmeasures from github with:
# install.packages("devtools")
devtools::install_github("transportfoundry/tvmeasures")To use the functions in tvmeasures, you need to load the library.
library(tvmeasures)There is a Shiny application that will aid non-programmers in using these functions for multiple projects. Start the application with the following command:
run_evaluation_app()The app will open in Chrome, and it contains its own documentation.
The library contains functions to compute the percentile and summed accessibility contained in project tiff files written out by Conveyal.
base <- read_tiff(system.file("extdata/base_am_jobs.tiff", package = "tvmeasures"))
pop <- read_tiff(system.file("extdata/pop_total_4326.tiff", package = "tvmeasures"))
beltline <- read_tiff(system.file("extdata/beltline_am_jobs.tiff", package = "tvmeasures"))
# percentile accessibility
compute_pctaccess(beltline, pop, probs = c(0.7, 0.9))
#> 70% 90%
#> 4324 30624
# percent difference between project and base
(sum_access(beltline) - sum_access(base)) / sum_access(base) * 100
#> [1] 0.2049587