Minimal – r.iresmi.net

Author

Michaël

Published

2022-11-16

Modified

2024-12-06

Photo of Piton de la Fournaise and Formica Leo — Piton de La Fournaise – CC BY-NC-ND by Jean-Paul Tonnelier

Day 16 of 30DayMapChallenge: « minimal » (previously).

Bare Réunion…

library(rayshader)
library(raster)
library(tidyverse)
library(fs)
library(httr)
library(glue)

data_dir <- path_expand("~/data/bdalti/974")

# https://geoservices.ign.fr/bdalti
if (!dir_exists(data_dir)) {
  dir_create(data_dir)
  
  GET("https://wxs.ign.fr/aqd29otkz2hofiee5pb0fygn/telechargement/prepackage/BDALTI-25M_PACK_REU_14-12-2020$BDALTIV2_2-0_25M_ASC_RGR92UTM40S-REUN89_D974_2016-03-11/file/BDALTIV2_2-0_25M_ASC_RGR92UTM40S-REUN89_D974_2016-03-11.7z",
      write_disk(glue("{data_dir}/dl.7z")))
  
  system(glue("7z e -y -o{data_dir} {data_dir}/dl.7z"))
}

# We get a bunch of ASCII files : open and merge, convert to matrix used by rayshader
elmat <- dir_ls(data_dir, glob = "*.asc") %>% 
  map(raster) %>% 
  reduce(merge) %>% 
  raster_to_matrix()

elmat %>%
  sphere_shade(texture = "desert") %>%
  add_shadow(ray_shade(elmat, zscale = 3), 0.5) %>%
  add_shadow(ambient_shade(elmat), 0) %>%
  plot_3d(elmat, zscale = 10, fov = 0, theta = 135, zoom = 0.75, phi = 45, windowsize = c(1000, 800))

render_snapshot("reunion_3d.jpeg")

A 3D view of Réunion Island — Bare Réunion

---
title: "Minimal"
description: "Day 16 of 30DayMapChallenge"
author: "Michaël"
date: "2022-11-16"
date-modified: last-modified
categories:
  - R
  - 30DayMapChallenge
  - datavisualization
  - raster
  - spatial 
draft: false
freeze: true
editor_options: 
  chunk_output_type: console
---

[![Piton de La Fournaise -- CC BY-NC-ND by Jean-Paul Tonnelier](images/15760055627_9fcc86aeb6_c.jpg){fig-alt="Photo of Piton de la Fournaise and Formica Leo"}](https://flic.kr/p/q1Ept2)

Day 16 of [30DayMapChallenge](https://30daymapchallenge.com/): « minimal » ([previously](/#category=30DayMapChallenge)).

Bare Réunion...

```{r}
#| eval: false

library(rayshader)
library(raster)
library(tidyverse)
library(fs)
library(httr)
library(glue)

data_dir <- path_expand("~/data/bdalti/974")

# https://geoservices.ign.fr/bdalti
if (!dir_exists(data_dir)) {
  dir_create(data_dir)
  
  GET("https://wxs.ign.fr/aqd29otkz2hofiee5pb0fygn/telechargement/prepackage/BDALTI-25M_PACK_REU_14-12-2020$BDALTIV2_2-0_25M_ASC_RGR92UTM40S-REUN89_D974_2016-03-11/file/BDALTIV2_2-0_25M_ASC_RGR92UTM40S-REUN89_D974_2016-03-11.7z",
      write_disk(glue("{data_dir}/dl.7z")))
  
  system(glue("7z e -y -o{data_dir} {data_dir}/dl.7z"))
}

# We get a bunch of ASCII files : open and merge, convert to matrix used by rayshader
elmat <- dir_ls(data_dir, glob = "*.asc") %>% 
  map(raster) %>% 
  reduce(merge) %>% 
  raster_to_matrix()

elmat %>%
  sphere_shade(texture = "desert") %>%
  add_shadow(ray_shade(elmat, zscale = 3), 0.5) %>%
  add_shadow(ambient_shade(elmat), 0) %>%
  plot_3d(elmat, zscale = 10, fov = 0, theta = 135, zoom = 0.75, phi = 45, windowsize = c(1000, 800))

render_snapshot("reunion_3d.jpeg")
```

![Bare Réunion](images/reunion_3d-1024x564.png){fig-alt="A 3D view of Réunion Island"}