Leaflet map nested in RShiny App - Improving speed & portability

I'll just second Barry's idea in particular, to set up as a standalone
webpage. You could even use QGIS and the QGIS2Web Plugin to create that,
and host via GitHub pages or similar.

From R, after creating a map via leaflet and similar packages, you can use
htmlwidgets::saveWidget() to export as a standalone .html file if I recall
correctly.

The one thing regarding a standalone webpage is that if you have a lot of
objects (especially complex ones), that can be a lot for a browser to
handle (given the data are part of the html file).  Might be worth some
quick experimentation, and simplifying polygons would help. (You could
always create a quick landing page, even generated via rMarkdown, and
having a link for maps by different regions or countries - then you could
have a folder of .html files you could distribute, and users could just
open the landing page, and navigate from there).

Just some quick thoughts... Hope this helps.
Mike T

On Wed, Sep 5, 2018 at 1:17 PM Erin Stearns <estearns88 at gmail.com> wrote:

Hello all,

Thank you all very much for the great insight!

*McCrea *- thank you very much, I will test using a geojson first, then
test after reducing geometry.

*Tim* - thank you for the great breakdown and recommended priority list.
Ideally, I would like to be able to share the interactive map with
teammates as a file or something akin to it such that they can simply open
it and interact with the map. RInno is a great option, however I run a
linux machine, so will look into further, but may need to find another
option.

*Roman* - the app is currently deployed to shinyapps.io. Thank you for
sharing about ShinyProxy -- so would this method require 1. Internet and
2.
local installation (vs internal server)?

*Barry* - wow, thank you for your response! Sounds like this would be the
best way to solve both issues. I am not as fluent with HTML and JS, but as
you say, there are likely great guides available to take this route.

Thank you all again, this has been hugely helpful. I wish you all the best
and hope I can be of help to you at some point!

Best,
Erin


On Wed, Sep 5, 2018 at 12:48 AM Barry Rowlingson <
b.rowlingson at lancaster.ac.uk> wrote:

On Wed, Sep 5, 2018 at 12:56 AM, Erin Stearns <estearns88 at gmail.com>
wrote:

Hello all!

I hope this message finds you all well!

I have 2 questions pertaining to the creation of interactive maps via
Leaflet nested inside an RShiny app. One question has to do with
computation while the other has to do with sharing/off-line

interactivity.

*Computation question*
As you see, the RShiny app takes quite a bit of time to render. Does
anyone
have any suggestions for improving this? As previously said, this

version

only contains 5 countries, thus I cannot continue with my current

method

to
reach a global map. I have considered finding centroids of all Admin 2
polygons and retaining attribute information here, then rasterizing the
malaria risk shapefile for visualization and using the 2 instead of a
single shapefile with polygon boundaries and attributes.

Unless you plan to add any computational functions to this map then I'd
strongly recommend creating it as a standalone web app and not a shiny

app.

This will enable you to use lots of useful Leaflet plugins for speeding
things up, such as only showing country outlines at low zoom levels, and
showing subdivisions only at high zoom levels. This *might* be possible
with R's various leaflet packages but I'd go for full javascript

control.

A standalone map would take its data from a JSON file or similar, and

you

would then be writing R code that generated that. The mapping app

itself is

written in HTML and JS with CSS styling. There are plenty of guides to
web-based interactive mapping, starting with Leaflet.

*Sharing the app/offline interactivity*
I am planning to share this with people who likely do not have R

installed

on their laptops nor have they ever coded. Does anyone have any
suggestions
for the best way to do this while retaining interactivity?

 Here's the big win of creating a standalone web map. You only have to

distribute the HTML/CSS/JS and they can be viewed directly (or you also
supply a tiny server that runs locally and only has to feed the files

on a

localhost port). No need to have a shiny server anywhere, or install R.

Its

simple and clean. It also needs no network connectivity, but you'll not

get

a base map - but you could include a low or medium resolution basemap
raster in your package.

The only reason to need Shiny here would be if you wanted people to do
something computational, like click on a bunch of polygons and then fit

a

linear model to the selection, since that would require a round-trip to

the

server for R to compute the fit. (although I suspect there's a JS

package

for linear modelling.... you can do ML in JS these days...)

Thank you all, any insight is greatly appreciated.

Best,
Erin

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