Update episodes/18-import-and-visualise-osm-data.Rmd

Co-authored-by: Claudiu Forgaci <[email protected]>

episodes/18-import-and-visualise-osm-data.Rmd

@@ -210,21 +210,25 @@ We have produced a proof a concept on Brielle, but can we factorise our work to
 We might replace the name in the first line and run everything again. Or we can create a function.
 ```{r reproducibility}
 extract_buildings <- function(cityname, year=1900){
-nominatim_polygon <- geo_lite_sf(address = cityname, points_only = FALSE)
-bb <- st_bbox(nominatim_polygon)
-x <- opq(bbox = bb) %>%
-   add_osm_feature(key = 'building') %>%
-   osmdata_sf()
-buildings <- x$osm_polygons %>%
-  st_transform(.,crs=28992)
-start_date <- as.numeric(buildings$start_date)
-buildings$build_date <- if_else(start_date < year, year, start_date)
- ggplot(data = buildings) +
-   geom_sf(aes(fill = build_date, colour=build_date))  +
-   scale_fill_viridis_c(option = "viridis")+
-   scale_colour_viridis_c(option = "viridis") +
-   ggtitle(paste0("Old buildings in ",cityname)) +
-   coord_sf(datum = st_crs(28992))
+  nominatim_polygon <- geo_lite_sf(address = cityname, points_only = FALSE)
+  bb <- st_bbox(nominatim_polygon)
+  
+  x <- opq(bbox = bb) %>%
+     add_osm_feature(key = 'building') %>%
+     osmdata_sf()
+     
+  buildings <- x$osm_polygons %>%
+    st_transform(.,crs=28992)
+    
+  start_date <- as.numeric(buildings$start_date)
+  
+  buildings$build_date <- if_else(start_date < year, year, start_date)
+   ggplot(data = buildings) +
+     geom_sf(aes(fill = build_date, colour=build_date))  +
+     scale_fill_viridis_c(option = "viridis")+
+     scale_colour_viridis_c(option = "viridis") +
+     ggtitle(paste0("Old buildings in ",cityname)) +
+     coord_sf(datum = st_crs(28992))
 }
 
 #test on Brielle