Add grow slider

[Robinlovelace]

To show an example of interactivity on the JS side.

[layik]

Few more tickets of prep and ship shaping other functions and will get on to this.

[layik]

Working on this.

[layik]

Not sure if a reprex would work but this should work on your machine

# git pull 
devtools::install()
gp_create()
# or just switch to a geoplumber app (should be backward compatible)
gp_sf(with_slider = TRUE)

That should give you

1. traffic locations data with cirlces
2. slider would grow the circles between 1 - 10

[layik]

more complicated examples on the way.

[layik]

working on adding "linewidth" to leaflet with slider component.

[layik]

linewidth added, one of the previous commits.

With last push, following should do a "server side" sf st_buffer of the uni_poly object. This is clearly easy on client side, using js packages like D3 or turf. What we are demonstrating here is React/R (geoplumber) can easily query the server for "R" power.

The reliance on JS/React knowledge in the snippet below will always be there until, someone, somewhere would write a package that would be able to "sythensize" React from R. I attribute this simplicity in the code to React's state/props paradigm.

gp_create(tolower(tempdir()))
cw <- setwd(tolower(tempdir()))
gp_is_wd_geoplumber()
gp_add_slider(
  min = 0.001,
  max = 0.01,
  step = 0.001
)
gp_change_file(
  path = "src/Welcome.js",
  what = '<GeoJSONComponent fetchURL={"http://localhost:8000/api/uol?grow=" + this.state.sliderInput} />
',
  pattern = '<GeoJSONComponent fetchURL="http://localhost:8000/api/uol" />',
  replace = TRUE,
  verbose = TRUE
)
gp_build()
gp_plumb()

We can close this and #43

[Robinlovelace]

This is awesome. Just playing with it now. Yes, I say, fantastic work.

[Robinlovelace]

Proof that the above code is reproducible: just reproduced it, as illustrated below, this project I think is close to take off :rocket:

[Robinlovelace]

Quick question/idea @layik: I think it would be interesting and very educational to show similar functionality done on the client side, e.g. with https://github.com/Turfjs/turf/tree/master/packages/turf-buffer

The benefit of the js solution is not just speed/resource use: it also has sensible units (I suggest km in this case)!

An example that would go really well in a vignette/paper on the subject (the vignette can become a paper). Heads-up @mpadge on that ; )

[layik]

ah, just see this. Thanks for checking on turf-buffer! Absolutely. Glad I was right in my assumption. Creating a new issue this one has dragged a little bit too far :)

[layik]

The GIF is going into the .Rmd. Thank you @Robinlovelace.