CODEWITHSUNDEEP
rdictionaryplotly
Malta
Malta

Reputation: 1983

Bad projection when using plot_geo in R Plotly

I try making maps using plotly, with plot_ly the result is great, but I found I should be using plot_geo, but can't manage to make it works.

I work with a France map in Lambert93 :

library(plotly)

download.file("https://www.data.gouv.fr/fr/datasets/r/087ab701-f21d-4046-b53e-8b647baf505d","dep.geojson")
dep <- sf::st_read("c:/users/sdaubree/Desktop/testplotly/101deps-lambert.geojson")

that plot correctly with plot_ly :

plot_ly(dep)

But not correctly with plot_geo :

plot_geo(dep)

As you can see, France is too wide this way.

I tried to change the CRS, as plot_geo give me the following message : The trace types 'scattermapbox' and 'scattergeo' require a projected coordinate system that is based on the WGS84 datum (EPSG:4326), but the crs provided is: '+proj=lcc +lat_0=46.5 +lon_0=3 +lat_1=49 +lat_2=44 +x_0=700000 +y_0=6600000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs'. Attempting transformation to the target coordinate system.

So I try to change the CRS myself :

dep84 <- sf::st_transform(dep,sp::CRS("EPSG:4326"))
plot_geo(dep84)

But it changes nothing to the result : France is still flat.

Upvotes: 0

Views: 412

Answers (1)

mrhellmann
mrhellmann

Reputation: 5499

This might be a problem with plot_geo()'s default projection, and zooming in on northern latitudes. There seems to be more than one way to fix this by changing arguments in a call to 'layout()`. A couple of them below:

# 1. by using scope 
plot_geo(dep) %>% 
  layout(geo = list(scope="europe"))

# 2. by changing projection type
plot_geo(dep) %>% 
  layout(geo = list(projection=list(type = 'natural earth1')))

Both pretty are narrower than the default. The 'wider' of the two ('natural earth1'):

enter image description here

Changing the crs of the objet wasn't necessary. A list of plotly projections if you want to find another.

The scope argument accepts either continent names or 'world' as far as I can tell.

Upvotes: 2

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