Again another bug on my code to calculate the distance between two points avoiding the coast.
Here are the raster data:
library(sf)
library(fasterize)
library(raster)
library(dplyr)
library(tidyverse)
library(stars)
library(gdistance)
spainurl <- "https://geo.vliz.be/geoserver/wfs?request=getfeature&service=wfs&version=1.0.0&typename=MarineRegions:coasts_subnational&outputformat=SHAPE-ZIP&filter=%3CPropertyIsEqualTo%3E%3CPropertyName%3Emrgid_1%3C%2FPropertyName%3E%3CLiteral%3E3417%3C%2FLiteral%3E%3C%2FPropertyIsEqualTo%3E"
download.file(spainurl, "spain.zip", mode = "wb")
unzip("spain.zip", exdir = "spain", junkpaths = TRUE)
franceurl <- "https://geo.vliz.be/geoserver/wfs?request=getfeature&service=wfs&version=1.0.0&typename=MarineRegions:coasts_subnational&outputformat=SHAPE-ZIP&filter=%3CPropertyIsEqualTo%3E%3CPropertyName%3Emrgid_1%3C%2FPropertyName%3E%3CLiteral%3E19888%3C%2FLiteral%3E%3C%2FPropertyIsEqualTo%3E"
download.file(franceurl, "france.zip", mode = "wb")
unzip("france.zip", exdir = "france", junkpaths = TRUE)
spainCoast_CoteBanyuls <- list.files("spain",
pattern = "shp$",
full.names = TRUE) %>% st_read()
frenchCoast_CoteBanyuls <- list.files("france",
pattern = "shp$",
full.names = TRUE) %>% st_read()
lines_spain <- st_geometry(spainCoast_CoteBanyuls) %>% st_cast("LINESTRING")
spainCoast_l <- st_sf(n = as.character(seq_len(length(lines_spain))), lines_spain)
lines_france <- st_geometry(frenchCoast_CoteBanyuls) %>% st_cast("LINESTRING")
franceCoast_l <- st_sf(n = as.character(seq_len(length(lines_france))), lines_france)
spainmax <- spainCoast_l[which.max(st_length(spainCoast_l)), ]
spainrest <- spainCoast_l[-which.max(st_length(spainCoast_l)), ]
joined <- c(st_geometry(spainmax), st_geometry(franceCoast_l)) %>%
st_union()
join_end <- st_union(joined, st_geometry(spainrest))
bbox_all <- st_bbox(joined) %>%
st_as_sfc()
polygon_joined <- bbox_all %>%
lwgeom::st_split(join_end) %>%
st_collection_extract("POLYGON")
#Polygons on position 2 and 3 need to be removed (visual inspection)
polygon_end <- polygon_joined[-c(2:3)]
polyCombin_df <- st_sf(var = 1, polygon_end)
polyCombin_df_t <- polyCombin_df %>% st_transform(25831)
r <- raster(polyCombin_df_t, res = 100)
r <- fasterize(polyCombin_df_t, r, fun = "max")
par(mar=c(2,2,1,1))
plot(r)
and Here I would like to calculate the distance between A = c(505470.9,4709364) and B = c(513902.9,4697052)
tr <- transition(r,transitionFunction= function(x) 1/mean(x), directions= 8)
costDistance(tr, c(505470.9,4709364), c(513902.9,4697052))
And here I get "Inf".
I guess my transition function is wrong. However, r is a raster with two values: 1 (land: not to cross) and < 1 (water => ok to cross) as you can see here:
.
So what did I do wrong ?
Thanks in advance for your help
Charlotte