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Linearize latitude-longitude GPS points on a provided route shape

Source: R/avl_cleaning.R
get_linear_distances.Rd

This functions projects raw AVL data, as GPS latitude-longitude points, onto a provided route geometry, returning each point's distance of that point along the shape its the beginning terminal.

Usage

get_linear_distances(
  avl_df,
  shape_geometry,
  clip_buffer = NULL,
  original_crs = 4326,
  project_crs = 4326
)

Arguments

avl_df

A dataframe of raw AVL data. Must include at least longitude and latitude columns. See validate_tides().

shape_geometry

The SF object to project onto. Must be only one shape. See get_shape_geometry().

clip_buffer

Optional. The distance, in units of the chosen spatial projection, to clip the GPS points. Only points within this distance of the shape_geometry will be kept. Default is NULL, where no clip will be applied.

original_crs

Optional. A numeric EPSG identifier. If a dataframe is provided for points, this will be used to define the coordinate system of the longitude / latitude values. Default is 4326 (WGS 84 ellipsoid).

project_crs

Optional. A numeric EPSG identifer indicating the coordinate system to use for spatial calculations. Consider setting to a Euclidian projection, such as the appropriate UTM zone. Default is 4326 (WGS 84 ellipsoid).

Value

The input avl_df with latitude and longitude columns replaced by a distance column, in the units of the spatial projection used (e.g., meters if using WGS UTM).

Examples

# Set my parameters
my_buffer <- 50 # meters
my_crs <- 32611

# Get input data
lineE_avl <- new_transittraj_data("lineE_avl")
lineE_shape <- new_transittraj_data("get_shape_geometry")
dim(lineE_avl)
#> [1] 3318   11

# Run function
lineE_dists <- get_linear_distances(avl_df = lineE_avl,
                                    shape_geometry = lineE_shape,
                                    clip_buffer = my_buffer,
                                    project_crs = my_crs)
dim(lineE_dists)
#> [1] 3268   10
head(lineE_dists)
#>                   location_ping_id service_date trip_id_performed    speed
#> 1 4af122e0b668d6821335d641a89ad312   2026-05-27          63383915 1.743456
#> 2 ef3b602e52fe3556a7539491e7792c74   2026-05-27          63383915 3.308096
#> 3 a940808be7f3a59066c981bffe3e537a   2026-05-27          63383915 2.145792
#> 4 6df05dfca51b44f25d403356de5a3e0a   2026-05-27          63383915 0.000000
#> 5 5326947f997dad696a09f510d4857d2c   2026-05-27          63383915 0.000000
#> 6 0eeafa189aab82fe0bff169a9dc587f7   2026-05-27          63383915 0.000000
#>       vehicle_id     event_timestamp direction_id        shape_id route_id
#> 1 1047-1048-1185 2026-05-27 05:48:58            0 804EB_RC_221121      804
#> 2 1047-1048-1185 2026-05-27 05:49:19            0 804EB_RC_221121      804
#> 3 1047-1048-1185 2026-05-27 05:49:40            0 804EB_RC_221121      804
#> 4 1047-1048-1185 2026-05-27 05:49:59            0 804EB_RC_221121      804
#> 5 1047-1048-1185 2026-05-27 05:50:20            0 804EB_RC_221121      804
#> 6 1047-1048-1185 2026-05-27 05:50:40            0 804EB_RC_221121      804
#>    distance
#> 1 197.58271
#> 2  99.22546
#> 3  98.72317
#> 4  62.66861
#> 5  83.11011
#> 6  31.67278