decode_geom {osrmr}

Transform encoded polylines to lat-lng data.frame.

Description

decode_geom() uses a decoding algorithm to decode polylines. (http://stackoverflow.com/questions/32476218/how- to-decode-encoded-polylines-from-osrm-and-plotting-route-geometry)

Usage

decode_geom(encoded, precision = stop("a numeric, either 5 or 6"))

Arguments

encoded

A character containing encoded polylines

precision

A numeric (either 5 or 6) to specify the precision of [lat,lng] encoding. (OSRM API v4 used precision 5 with "polyline", OSRM API v5 uses precision 6 with "polyline6")

Value

data.frame with lat and lng

Examples

decoded_api_4 <- decode_geom(osrmr::encoded_string_api_4, precision = 5)
decoded_api_5 <- decode_geom(osrmr::encoded_string_api_5, precision = 6)
decoded_api_4[1:3,]
#        lat     lng
# 1 47.10020 8.09970
# 2 47.09850 8.09207
# 3 47.09617 8.09118
decoded_api_5[1:3,]
#        lat      lng
# 1 47.10020 8.099703
# 2 47.09850 8.092074
# 3 47.09617 8.091181
assertthat::assert_that(all.equal(decoded_api_4, decoded_api_5, tolerance = 1e-6))