shapes tableR/convert_sf_to_shapes.R
convert_sf_to_shapes.RdConverts a LINESTRING sf object into a GTFS shapes table.
convert_sf_to_shapes(sf_shapes, shape_id = NULL, calculate_distance = TRUE)A LINESTRING sf associating each shape_ids to a
geometry. This object must use CRS WGS 84 (EPSG code 4326).
A character vector specifying the shape_ids to be
converted. If NULL (the default), all shapes are converted.
A logical. Whether to calculate and populate the
shape_dist_traveled column. This column is used to describe the distance
along the shape from each one of its points to its first point. Defaults to
TRUE.
A data.table representing a GTFS shapes table.
data_path <- system.file("extdata/spo_gtfs.zip", package = "gtfstools")
gtfs <- read_gtfs(data_path)
# first converting existing shapes table into a sf object
shapes_sf <- convert_shapes_to_sf(gtfs)
head(shapes_sf)
#> Simple feature collection with 6 features and 1 field
#> Geometry type: LINESTRING
#> Dimension: XY
#> Bounding box: xmin: -46.98404 ymin: -23.73644 xmax: -46.63535 ymax: -23.19474
#> Geodetic CRS: WGS 84
#> shape_id geometry
#> 1 17846 LINESTRING (-46.63535 -23.5...
#> 2 17847 LINESTRING (-46.87255 -23.1...
#> 3 17848 LINESTRING (-46.64073 -23.5...
#> 4 17849 LINESTRING (-46.98404 -23.5...
#> 5 17850 LINESTRING (-46.77604 -23.5...
#> 6 17851 LINESTRING (-46.69711 -23.7...
# by default converts all shapes
result <- convert_sf_to_shapes(shapes_sf)
result
#> shape_id shape_dist_traveled shape_pt_lon shape_pt_lat shape_pt_sequence
#> <char> <num> <num> <num> <int>
#> 1: 17846 0.00000 -46.63535 -23.53517 1
#> 2: 17846 13.55178 -46.63548 -23.53513 2
#> 3: 17846 95.86978 -46.63626 -23.53494 3
#> 4: 17846 184.81732 -46.63710 -23.53473 4
#> 5: 17846 211.17349 -46.63735 -23.53466 5
#> ---
#> 12291: 68962 26058.05526 -46.64066 -23.54921 628
#> 12292: 68962 26067.76199 -46.64057 -23.54922 629
#> 12293: 68962 26094.30002 -46.64033 -23.54913 630
#> 12294: 68962 26132.70120 -46.63995 -23.54910 631
#> 12295: 68962 26162.11007 -46.63967 -23.54907 632
# shape_id argument controls which shapes are converted
result <- convert_sf_to_shapes(shapes_sf, shape_id = c("17846", "17847"))
result
#> shape_id shape_dist_traveled shape_pt_lon shape_pt_lat shape_pt_sequence
#> <char> <num> <num> <num> <int>
#> 1: 17846 0.00000 -46.63535 -23.53517 1
#> 2: 17846 13.55178 -46.63548 -23.53513 2
#> 3: 17846 95.86978 -46.63626 -23.53494 3
#> 4: 17846 184.81732 -46.63710 -23.53473 4
#> 5: 17846 211.17349 -46.63735 -23.53466 5
#> ---
#> 1090: 17847 60507.76810 -46.63735 -23.53466 543
#> 1091: 17847 60534.12426 -46.63710 -23.53473 544
#> 1092: 17847 60623.07180 -46.63626 -23.53494 545
#> 1093: 17847 60705.38981 -46.63548 -23.53513 546
#> 1094: 17847 60718.94158 -46.63535 -23.53517 547
# calculate_distance argument controls whether to calculate
# shape_dist_traveled or not
result <- convert_sf_to_shapes(shapes_sf, calculate_distance = TRUE)
result
#> shape_id shape_dist_traveled shape_pt_lon shape_pt_lat shape_pt_sequence
#> <char> <num> <num> <num> <int>
#> 1: 17846 0.00000 -46.63535 -23.53517 1
#> 2: 17846 13.55178 -46.63548 -23.53513 2
#> 3: 17846 95.86978 -46.63626 -23.53494 3
#> 4: 17846 184.81732 -46.63710 -23.53473 4
#> 5: 17846 211.17349 -46.63735 -23.53466 5
#> ---
#> 12291: 68962 26058.05526 -46.64066 -23.54921 628
#> 12292: 68962 26067.76199 -46.64057 -23.54922 629
#> 12293: 68962 26094.30002 -46.64033 -23.54913 630
#> 12294: 68962 26132.70120 -46.63995 -23.54910 631
#> 12295: 68962 26162.11007 -46.63967 -23.54907 632