shiny + geemap

[cidreNMBU]

Hello,

I am an R user who has been using the rgee package for a while, but unfortunately, it might not be longer maintained (see this issue. One thing that was great about rgee was the possibility of creating Shiny Applications using R Shiny thanks to the effort of Cesar of creating this template which unfortunately is no longer working.

However, Shiny for Python was released less than 2 years ago and I think it would be a good chance to create applications that use geemap in the backend. The issue is that it's not very straightforward to develop a Shiny Application that uses geemap because it's necesary to use a token or other authentication way.

I was wondering if you are interested in creating an automated pipeline like the one that was created for rgee (pipeline to deploy).

Best regards,
Cidre

[giswqs]

@cidreNMBU Thank you for submitting the feature request. I have not followed the development of rgee for a while and I am surprised and sad to see that rgee is no longer actively maintained. I am not an R user and I don't know if I would be able to develop and maintain a shiny app for geemap.

However, I have recently discovered the py-maplibregl package, which supports Rshiny integration. I am working on adding the maplibre support for leafmap. I guess it should work for geemap as well. I will see if I can get a proof of concept soon.

Contributions are always welcome.

from maplibre import Map, MapContext, output_maplibregl, render_maplibregl
from maplibre.controls import Marker
from shiny import App, reactive, ui

app_ui = ui.page_fluid(
    output_maplibregl("maplibre", height=600),
    ui.div("Click on map to set a marker"),
)


def server(input, output, session):
    @render_maplibregl
    def maplibre():
        m = Map()
        return m

    @reactive.Effect
    @reactive.event(input.maplibre)
    async def coords():
        async with MapContext("maplibre") as m:
            print(input.maplibre())
            lng_lat = tuple(input.maplibre()["coords"].values())
            marker = Marker(lng_lat=lng_lat)
            m.add_marker(marker)
            m.add_call("flyTo", {"center": lng_lat})


app = App(app_ui, server)

if __name__ == "__main__":
    app.run()

[cidreNMBU]

Thank you for your quick answer @giswqs.

Actually, there's support and fantastic integration of ipyleaflet through the shinywidgets package. My feature request is related to support the deployment of the application maybe through shinyapps.io. Here I have a reproducible example of a simple app:

import ee
from shiny import App, reactive, render, ui
from shinywidgets import output_widget, render_widget
from faicons import icon_svg

ee.Initialize()

app_ui = ui.page_sidebar(
    ui.sidebar(
        ui.input_action_button(
            'button',
            'Generate map',
            icon = icon_svg('play')
        )
    ),
    ui.layout_column_wrap(
       output_widget('result')
    ),
    title    = "Test geemap",
    fillable = True,
)


def server(input, output, session):

    @reactive.calc
    @reactive.event(input.button)
    def generate_map():

        Map = geemap.Map(center=[40, -100], zoom=4)
        
        landsat7 = (
              ee.Image('LANDSAT/LE7_TOA_5YEAR/1999_2003')
              .select(['B1', 'B2', 'B3', 'B4', 'B5', 'B7'])
        )
        
        landsat_vis = {'bands': ['B4', 'B3', 'B2'], 'gamma': 1.4}
        
        Map.addLayer(landsat7, landsat_vis, "Landsat")
        
        hyperion = ee.ImageCollection('EO1/HYPERION').filter(ee.Filter.date('2016-01-01', '2017-03-01'))
        
        hyperion_vis = {
             'min': 1000.0,
             'max': 14000.0,
             'gamma': 2.5,
             }
        Map.addLayer(hyperion, hyperion_vis, 'Hyperion')

        return Map
    
    @output
    @render_widget
    def result():
        return generate_map()


app = App(app_ui, server)

The issue arises because when deploying the app it looks for the credentials file. In rgee this was the template content for deployment:

# 1. Create the credentials file
ee_Initialize()

# 2. Copy credentials file to the project folder
file_credentials <- sprintf("%s/credentials", dirname(rgee::ee_get_earthengine_path()))
file.copy(file_credentials, to = ".")

# 3. Set ShinyApps account info
# FIRST MODIFY LOCAL .Renviron!!
error_on_missing_name <- function(name){
  var <- Sys.getenv(name, unset=NA)
  if(is.na(var)){
    stop(paste0("cannot find ",name),call. = FALSE)
  }
  gsub("\"", '',var)
}

rsconnect::setAccountInfo(name   = error_on_missing_name("SHINY_ACC_NAME"),
               token  = error_on_missing_name("TOKEN"),
               secret = error_on_missing_name("SECRET"))


# 4. Run the application
rsconnect::deployApp(
  appFiles = c("app.R", "utils.R", "credentials"),
  appTitle = "rgee_app_demo",
  lint = FALSE
)

# 5. Delete EE credentials file
file.remove("credentials")

I suppose something similar can be achieved with geemap . I think the steps consist on:

1. Get credentials file info
2. Create a temporary copy on the Shiny App directory
3. Set up the account information of shinyapps.io using environment variables
4. Run the app
5. Delete the copy of the credentials file

I am not sure if rsconnect for python has these built-in functions to create a deploy template like this one. As far as I know, the rsconnect package in Python uses the command line to deploy apps, but I am still a beginner in Python to know how to do this. So, do you think that it would be possible and a good idea to work in a template that helps to deploy an app with security (keeping account info in environment variables and managing credentials)?

[giswqs]

Great to hear that shinywidgets support ipyleaflet. Does shiny app supports setting environment? If yes, set the environment EARTHENGINE_TOKEN to the contents of the credentials file. geemap should be able to retrieve the env variable and generate the credentials file. See example at https://github.com/opengeos/solara-geemap