Merge pull request #34 from richardellison/master

Addition of gtfs2sldf function.

DESCRIPTION

@@ -26,6 +26,8 @@ Imports:
     rgdal,
     rgeos,
     dplyr,
+    magrittr,
+    geosphere,
     RgoogleMaps,
     openxlsx,
     leaflet,

NAMESPACE

@@ -21,6 +21,7 @@ export(format_stats19_ve)
 export(gclip)
 export(graphhopper_pat)
 export(gsection)
+export(gtfs2sldf)
 export(islines)
 export(line2df)
 export(line2points)

R/gtfs.R

@@ -0,0 +1,76 @@
+#' Import GTFS shapes and route data to SpatialLinesDataFrame.
+#'
+#' Takes a string with the file path of the zip file with the GTFS feed,
+#' imports the shapes (geometry), route and agency data and returns a
+#' SpatialLinesDataFrame for the GTFS feed.
+#'
+#' @param gtfszip String with the file path of the GTFS feed zip file
+#' @export
+#' @examples \dontrun{
+#' downloader::download("http://www.yrt.ca/google/google_transit.zip",
+#'                      paste0(tempdir(),"/gtfsfeed.zip"))
+#' yrtgtfs <- gtfs2sldf(paste0(tempdir(),"/gtfsfeed.zip"))
+#' plot(yrtgtfs,col=paste0("#",yrtgtfs$route_color))
+#' }
+gtfs2sldf <- function(gtfszip = "") {
+
+  if (gtfszip == "") {
+    stop("Zip file required")
+  }
+  if (file.exists(gtfszip) == FALSE) {
+    stop("Specified zip file does not exist")
+  }
+
+  `%>%` <- magrittr::`%>%`
+  gtfsfiles <- unzip(gtfszip, exdir = tempdir())
+
+  gtfstrips <- read.csv(paste0(tempdir(),"/trips.txt"))
+  gtfsroutes <- read.csv(paste0(tempdir(),"/routes.txt"))
+  gtfsagency <- read.csv(paste0(tempdir(),"/agency.txt"))
+  gtfsshape <- read.csv(paste0(tempdir(),"/shapes.txt"))
+
+  unlink(gtfsfiles)
+
+  gtfslines <- sp::SpatialLinesDataFrame((gtfsshape %>%
+      dplyr::group_by(shape_id) %>%
+      dplyr::arrange(shape_pt_sequence) %>%
+      dplyr::do(
+        gtfsline = sp::Lines(sp::Line(as.matrix(.[,c('shape_pt_lon','shape_pt_lat')])),unique(.$shape_id))
+      ) %>%
+      dplyr::ungroup() %>%
+      dplyr::do(
+        gtfsline = sp::SpatialLines(.[[2]],
+                                    proj4string = sp::CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"))))[[1]][[1]],
+   data=gtfstrips %>%
+     dplyr::inner_join(
+       gtfsroutes
+     ) %>%
+     dplyr::distinct(
+       route_id,
+       shape_id,
+       route_short_name,
+       route_long_name,
+       route_desc,
+       route_type,
+       route_color,
+       route_text_color,
+       agency_id
+     ) %>%
+     dplyr::select(route_id,
+            shape_id,
+            route_short_name,
+            route_long_name,
+            route_desc,
+            route_type,
+            route_color,
+            route_text_color,
+            agency_id) %>%
+     dplyr::inner_join(
+       gtfsagency
+     ) %>%
+     dplyr::do(
+       `rownames<-`(.,.$shape_id)
+     ))
+  rm(gtfstrips,gtfsshape,gtfsagency,gtfsroutes)
+  return(gtfslines)
+}