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question on the use of Leaflet for plotting points and rater GeoTIFF

5 messages · Gabriel Cotlier, Ben Tupper

Original
Gabriel Cotlier
# 
Hello.

I would like to use Leaflet package to plot over a Google Satellite base
map :

1.  a shapefile of polygon
2.  a shapefile of points
3,  a GeoTIFF image

I could use the Leaflet package to get plotted successfully only the first
Item of the list above with the following code :

require(rgdal)
library(rgeos)
library(raster)

shapeData <- raster::shapefile('Seattle_boundries.shp')
shapeData <- spTransform(shapeData, CRS("+proj=longlat +ellps=GRS80"))

leaflet() %>%
  addTiles(urlTemplate = "
https://mts1.google.com/vt/lyrs=s&hl=en&src=app&x={x}&y={y}&z={z}&s=G",
attribution = 'Google')  %>%
  addPolygons(data=shapeData,weight=5,col = 'red')

How is it possible to find a way to complete the code above for plotting
the item 2 and 3 as well in the same Leaflet figure.

Is there any possible solution that can enable this task?

Thanks for your help.

Kind regards
Gabriel
Ben Tupper
# 
Hi,

See the "markers" and "raster images" sections here
http://rstudio.github.io/leaflet/markers.html

Cheers,
Ben
On Thu, Aug 12, 2021 at 5:02 AM Gabriel Cotlier <gabiklm01 at gmail.com> wrote:

            

      
      
      
    

        

      
      
    

        

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Gabriel Cotlier
    

    

      
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Dear Ben,

Thanks a lot for your help!
Actually it worked very well for me with the link you gave me.
However, for some reason the numbers of the values in color scale goes from
the lower values set at the top  (blue) of the sacale to the higher values
set at the bottom (red ) and it would be better for me if it goes from from
the lower values in the bottom (blue) to higher value in the top (red),
since is temperature going from the lower to the higher.
 Another issue I found a bit problematic for me to modify is that the color
palette is too "light", for instance not like the color palette "Jet" in
Matlab or Python, it seems as if the intensity of the colors of the
temperature colors is low or light maybe is a transparency and should
change opacity ....?

Maybe you or somebody knows a possible way to improve these two issues a
bit ?

Here is the code :

# color palettes
# pal <- colorNumeric(palette = "Spectral", values(raster), na.color =
"transparent" , reverse = TRUE)
pal <- colorNumeric(palette = "RdYlBu", values(raster), na.color =
"transparent" , reverse = TRUE)

# plot map
leaflet() %>%
  addTiles(urlTemplate = "
https://mts1.google.com/vt/lyrs=s&hl=en&src=app&x={x}&y={y}&z={z}&s=G",
attribution = 'Google')  %>%
  addPolygons(data = polygon,weight=5,col = 'black')  %>%
  addCircles(data = points, color = "White", radius = 500, fillOpacity =
1,opacity = 9)%>%
  addRasterImage(raster, project = FALSE, colors = pal) %>%
  addLegend(pal = pal, values = values(raster), title = "Temperature",
opacity = 9)  # ,labFormat = labelFormat(transform = function(x) sort(x,
decreasing = TRUE)))

Thanks a lot again for your help.
Kind regards,
Gabriel

        
On Thu, Aug 12, 2021 at 5:07 PM Ben Tupper <btupper at bigelow.org> wrote:

        

            

      
      
      
    

        

      
      
    

            

      
      
      
    

        

  
  


  


      

    

    

      
      

        


  

        

      Ben Tupper
    

    

      
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Hi,

I don't think we can run the code since it isn't reproducible (see
https://CRAN.R-project.org/package=reprex
<https://cran.r-project.org/package=reprex> for help with that.)  But here
are some hints:

flipped color bar - I love to use RSeek.org which is an R-centric search
engine -  you may want to bookmark it or add it to your search engine list
if your browser supports that. https://rseek.org/?q=leaflet+flip+color+bar
This search hits a number of discussions on flipping the color bar.

color intensity - oooooh, there is so much discussion in the world about
colors.  By default raster images have opacity of 1 (fully opaque) when
rendered in leaflet, so really it is a matter of finding the color table
you want and then applying colorNumeric judiciously.  For me it comes down
to trial and error.  If you are looking for eye pop! then perhaps check out
the viridis options.  See ?colorNumeric

Cheers,
Ben

        
On Thu, Aug 12, 2021 at 2:24 PM Gabriel Cotlier <gabiklm01 at gmail.com> wrote:

        

            

      
      
      
    

        

      
      
    

            

      
      
      
    

        

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Gabriel Cotlier
    

    

      
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Dear Ben,

Thanks a lot for your help with the useful and appropriate link you sent
me. There was the solution for the flipping of the colorbar.
I could finally flip the color bar and it worked out correctly. I also
found a little bit less opaque color palette, that is the matlab "jet"
color in the R "matlab" package, but it is still a bit opaque for
my personal taste. I will give it some trials and errors with many
different opacities to see what happened.

Thanks a lot again for your helpful advice and guidance,

Kind regards,
Gabriel

        
On Fri, Aug 13, 2021 at 3:00 PM Ben Tupper <btupper at bigelow.org> wrote: