---
title: "smartmap"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{smartmap}
  %\VignetteEncoding{UTF-8}
  %\VignetteEngine{knitr::rmarkdown}
editor_options: 
  chunk_output_type: console
---

```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
library(leaflet)
library(leafsync)
```

```{r setup}
library(smartmap)
```
smartmap produces interactive maps from a variety of R objects with minimal 
coding required. This makes it great for previewing spatial data. It provides
only three functions:

* `smap()`: The core function. Smartly create [leaflet](https://rstudio.github.io/leaflet/)
  maps from R objects. Maps created with `smap()` contain two dialogues in the top
  right corner: one for switching the background map and one for measuring 
  distances and areas.
* `smart_as_sf()`: Applies the same heuristics as `smap()`, but returns 
  [sf](https://r-spatial.github.io/sf/) objects instead.
* `as_coord_matrix`: Applies the same heuristics as `smap()`, but returns a 
  numeric matrix with longitude and latitude instead.

## Data frames

Viewing `data.frames` with longitude and latitude columns was the basic use case
for which smartmap was created. The heuristics for automatically determining
the geo-coordinate columns are simple, but should work for most use
cases.

```{r echo = FALSE}
cities <- data.frame(
  city = c("Bregenz", "Eisenstadt", "Wiener Neustadt",
    "Graz", "Klagenfurt", "Linz", "Salzburg", "Innsbruck",
    "Vienna"),
  LaTituDE = c(47.51669707, 47.83329908, 47.81598187,
    47.0777582, 46.62034426, 48.31923281, 47.81047833,
    47.28040733, 48.20001528),
  lng = c(9.766701588, 16.53329747, 16.24995357,
    15.41000484, 14.3100203, 14.28878129, 13.0400203,
    11.4099906, 16.36663896),
  pop = c(26928, 13165, 60621.5, 242780, 88588, 265161.5,
    178274, 133840.5, 2065500),
  country = c("Austria", "Austria", "Austria", "Austria",
    "Austria", "Austria", "Austria", "Austria", "Austria"),
  province = c("Vorarlberg", "Burgenland",
    "Niederösterreich", "Steiermark", "Kärnten",
    "Oberösterreich", "Salzburg", "Tirol", "Wien")
)
```

```{r eval = FALSE}
print(cities)
smap(cities)
```
```{r out.width = "100%", echo = FALSE}
print(cities)
smap(cities)
```
<p style="font-size:8pt">
    source: [World Cities Database](https://simplemaps.com/data/world-cities)
</p>

## Shapefiles

`smap()` also works with file system paths or urls to shapefiles. It even
looks inside zip files if necessary!

```{r cache = TRUE, out.width = "100%"}
# disabled url broken
# smap("https://www.naturalearthdata.com/http//www.naturalearthdata.com/download/50m/cultural/ne_50m_admin_0_countries.zip")

```

## Point coordinates

Numeric vectors of length 2 are interpreted as longitude/latitude coordinate 
pairs. If you supply names, smap uses them to identify the correct order. 

```{r eval = FALSE}
smap(c(16.422524, 48.185686))
smap(c(LAT = 48.185686, LoNgItuDE = 16.422524))
```
```{r out.width = "100%", echo = FALSE}
smap(c(LAT = 48.185686, LoNgItuDE = 16.422524))
```


## Leaflet maps

You can call `smap()` on existing leaflet objects to add background tiles and
a ruler for measuring distance

```{r, eval=FALSE}
library(leaflet)
lf <- leaflet::leaflet(height=200) %>% 
  leaflet::addCircleMarkers(lng = 16.422524, lat = 48.185686)

lf
smap(lf)
```
```{r, echo = FALSE}
library(leaflet)
lf <- leaflet::leaflet(height=200) %>% 
  leaflet::addCircleMarkers(lng = 16.422524, lat = 48.185686)

leafsync::sync(lf, smap(lf), sync.cursor = FALSE)

```


## Simple features (sf) 

Everyone who has worked with simple features will know that it is sometimes a
bit awkward to convert between the different datatypes provided by the package
(`sf::sf`, `sf::sfc` and `sf::sfg`). Toe remedy this `smap()` works natively
with all three.


```{r, eval = FALSE}
smap(sf::st_point(c(16.373311, 48.208482)))
smap(sf::st_sfc(sf::st_point(c(16.373311, 48.208482))))
smap(sf::st_sf(coords = sf::st_sfc(sf::st_point(c(16.373311, 48.208482))), crs = 4326))
```
```{r out.width = "100%", echo = FALSE}
smap(sf::st_sf(coords = sf::st_sfc(sf::st_point(c(16.373311, 48.208482))), crs = 4326))
```