note-lecture1-ogh.qmd

---
title: "Untitled"
# output: html_document
date: "2023-08-28"
---

These are the packages we'll use:

```{r}
library(sf)
library(tidyverse)
knitr::opts_chunk$set(eval = FALSE)
```

```{r}
library(spData)
names(world)
world
```


```{r}
poland = world[world$name_long == "Poland", 1]
dim(poland)
names(poland)
poland_df = sf::st_drop_geometry(poland)
class(poland)
class(poland_df)
plot(poland)
plot(poland_df)
```

Tidyverse way:

```{r}
poland = world |>
  filter(name_long == "Poland") |>
  select(name_long, pop, area_km2)
```


## Data from Poznan

```{r}
u = "https://github.com/Robinlovelace/opengeohub2023/releases/download/data/data.zip"
f = basename(u)
f
options(timeout = 600)
download.file(url = u, f)
unzip(f)
```

```{r}
list.files("data/")
list.files("data/osm")
```

```{r}
pol_all = read_sf("data/osm/gis_osm_transport_a_free_1.shp")
pol_all
plot(pol_all)
```

```{r}
pol_bus = pol_all |> 
  filter(str_detect(name, "bus"))

pol_bus_station = pol_all |> 
  filter(fclass == "bus_station")

mapview::mapview(pol_bus_station)

pol = pol_all |> 
  filter(str_detect(name, "Port*.+P"))

pol |>
  ggplot() +
  geom_sf()

library(tmap)
tmap_mode("view")
tm_shape(pol) +
  tm_borders()
```

Create pois:

```{r}
poi_df = tribble(
  ~name, ~lon, ~lat,
  "Faculty",        16.9418, 52.4643,
  "Hotel ForZa",    16.9474, 52.4436,
  "Hotel Lechicka", 16.9308, 52.4437,
  "FairPlayce",     16.9497, 52.4604
)
poi_df
poi_sf = sf::st_as_sf(poi_df, coords = c("lon", "lat"))
sf::st_crs(poi_sf) = "EPSG:4326"
```

```{r}
stop_raw = read_csv("data/gtfs/stops.txt")
stops_df = stop_raw |> 
  select(-stop_code)
stops = sf::st_as_sf(stops_df, coords = c("stop_lon", "stop_lat"))
sf::st_crs(stops)
sf::st_crs(stops) = "EPSG:4326"
sf::st_crs(stops)
```

```{r}
pois_buffer = sf::st_buffer(poi_sf, 150)
stops_in_buffer = stops[pois_buffer, ]

stops_not_in_buffer = stops[pois_buffer, , op = sf::st_disjoint]
nrow(stops_in_buffer)
nrow(stops_not_in_buffer)

stops_not_in_buffer = stops |> 
  filter(!stop_id %in% stops_in_buffer$stop_id)
nrow(stops)
nrow(stops_in_buffer)
crsuggest::suggest_crs(stops_in_buffer)

stops_not_in_buffer2 = sf::st_difference(stops, sf::st_union(pois_buffer))

plot(pois_buffer$geometry[1])

pois_buffer2 = stplanr::geo_buffer(poi_sf, dist = 150)
plot(pois_buffer2$geometry[1])

pois_joined = sf::st_join(pois_buffer, stops)

stops_joined = stops |> 
  filter(stop_id %in% pois_joined$stop_id)

stops_joined$geometry_txt = sf::st_as_text(stops_joined$geometry)

pois_joined2 = left_join(
  pois_joined,
  stops_joined |>
    select(stop_id, geometry_txt) |> 
  sf::st_drop_geometry()
  )
```