Scott Chamberlain

[parzer](https://github.com/ropensci/parzer) is a new package for
handling messy geographic coordinates.The first version is now on CRAN,
with binaries coming soon hopefully (seenote about installation below).
The package recently [completed
rOpenScireview](https://github.com/ropensci/onboarding/issues/341).

## parzer motivation

The idea for this package started with a tweet from [Noam
Ross](https://ropensci.org/author/noam-ross/)(<https://twitter.com/noamross/status/1070733367522590721>)
about 15 months ago.

The idea being that sometimes you have geographic coordinates in a
messyformat, or in many different formats, etc. You can think of it as
beingthe package for geographic coordinates that
[lubridate](https://cloud.r-project.org/web/packages/lubridate/) is for
dates.

I started off thinking about wrapping a Javascript library with
[Jeroen's](https://ropensci.org/author/jeroen-ooms/)[V8](https://cloud.r-project.org/web/packages/V8/)
R package, but then someone showed me or I found (can't remember) [some
C++
code](https://www.codeproject.com/Articles/15659/Longitude-Latitude-String-Parser-and-Formatter)from
back in 2006 that seemed appropriate. I figured I'd go down the C++track
instead of the Javascript track because I figured I could likely
getbetter performance out of C++ and have slightly less install
headaches for users.

## Package installation

The package is on CRAN so you can use `install.packages`

::: {.highlight}
``` {.chroma tabindex="0"}
install.packages("parzer")
```
:::

However, since this package requires compilation you probably want a
binary.Binaries are not available on CRAN yet. You can install a binary
like

::: {.highlight}
``` {.chroma tabindex="0"}
install.packages("parzer", repos = "https://dev.ropensci.org/")
```
:::

::: {.highlight}
``` {.chroma tabindex="0"}
library(parzer)
```
:::

Check out the package documentation to get started:
<https://docs.ropensci.org/parzer/>

## Package basics

The following is a summary of the functions in the package and what they
do:

Parse latitude or longitude separately

- parse_lat
- parse_lon

Parse latitudes and longitudes at the same time

- parse_lon_lat

Parse into separate parts of degrees, minutes, seconds

- parse_parts_lat
- parse_parts_lon

Pull out separately degrees, minutes, seconds, or hemisphere

- pz_degree
- pz_minute
- pz_second
- parse_hemisphere

Add/subtract degrees, minutes, seconds

- pz_d
- pz_m
- pz_s

Some examples:

parse latitudes and longitudes

::: {.highlight}
``` {.chroma tabindex="0"}
lats <- c("40.123°", "40.123N74.123W", "191.89", 12, "N45 04.25764")parse_lat(lats)#> Warning in pz_parse_lat(lat): invalid characters, got: 40.123n74.123w#> Warning in pz_parse_lat(lat): not within -90/90 range, got: 191.89#>   check that you did not invert lon and lat#> [1] 40.12300      NaN      NaN 12.00000 45.07096
```
:::

::: {.highlight}
``` {.chroma tabindex="0"}
longs <- c("45W54.2356", "181", 45, 45.234234, "-45.98739874N")parse_lon(longs)#> Warning in pz_parse_lon(lon): invalid characters, got: -45.98739874n#> [1] -45.90393 181.00000  45.00000  45.23423       NaN
```
:::

Sometimes you may want to parse a geographic coordinate into its
componentparts; `parse_parts_lat` and `parse_parts_lon` are what you
need:

::: {.highlight}
``` {.chroma tabindex="0"}
x <- c("191.89", 12, "N45 04.25764")parse_parts_lon(x)#> Warning in pz_parse_parts_lon(scrub(str)): invalid characters, got: n45 04.25764#>   deg min      sec#> 1 191  53 23.99783#> 2  12   0  0.00000#> 3  NA  NA      NaN
```
:::

::: {.highlight}
``` {.chroma tabindex="0"}
pz_d(31)#> 31pz_d(31) + pz_m(44)#> 31.73333pz_d(31) - pz_m(44)#> 30.26667pz_d(31) + pz_m(44) + pz_s(59)#> 31.74972pz_d(-121) + pz_m(1) + pz_s(33)#> -120.9742
```
:::

## Use cases

Check out the [parzer use
cases](https://docs.ropensci.org/parzer/articles/use_cases.html)
vignette on the docs site.[Get in
touch](https://github.com/ropensci/parzer/issues) if you have a use case
thatmight be good to add to that vignette.

## Thanks

Thanks to the reviewers [Maria Munafó](https://github.com/mvickm)and
[Julien Brun](https://github.com/brunj7) for their time investedin
improving the package.

## To Do

There's more to do. We are thinking about [dropping the Rcpp
dependency](https://github.com/ropensci/parzer/issues/17),support
[parsing strings that have both latitude and longitude
together](https://github.com/ropensci/parzer/issues/3),[making error
messages better](https://github.com/ropensci/parzer/issues/5), and more.


parzer is a new package for handling messy geographic coordinates.The first version is now on CRAN, with binaries coming soon hopefully (seenote about installation below). The package recently completed rOpenScireview.parzer motivation  The idea for this package started with a tweet from Noam Ross(https://twitter.com/noamross/status/1070733367522590721) about 15 months ago.

Messages de Rogue Scholar

parzer: Parse Messy Geographic Coordinates