Transparency not working with addGeotiff and colorOptions

[psolymos]

I am having issues with transparent colors for the NA values in the raster (GeoTIFF). I tried different values for na.color = "transparent" and all gave the same black result, using CRAN (v 0.1.6) and dev (SHA1 660d9886) being the same in this regard.

library(leaflet)
library(leafem)

leaflet() %>%
        addProviderTiles("Esri.WorldImagery") %>%
        addGeotiff(
          url = "https://peter.solymos.org/testapi/amro1k.tif",
          project = FALSE,
          opacity = 0.8,
          colorOptions = colorOptions(
             palette = hcl.colors(50, palette = "inferno"), 
             domain = c(0, 0.62),
             na.color = "transparent"))

[tim-salabim]

This is a tricky one.

The georaster.noDataValue just doesn't quite match the current value being processed (vals), even though it should...

@DanielJDufour any ideas how to catch this? Is there an alternative to checking via vals === georaster.noDataValue (whoch is what I'm currently doing - https://github.com/r-spatial/leafem/blob/master/inst/htmlwidgets/lib/georaster-for-leaflet/georaster-binding.js#L108)?

[tim-salabim]

This seems to work:

vals.toExponential(7) === georaster.noDataValue.toExponential(7)

whereas a value of 8 returns false

[tim-salabim]

and it seems to fix the issue

[psolymos]

Making sure I understand: georaster.noDataValue is the value taken from the TIF, and it is not matching with what georaster expects (a numerical thing when evaluating?). Should noDataValue be set when saving the TIF?

[tim-salabim]

Yes, correct. Can you set the noDataValue when saving the .tif?

[psolymos]

raster::NAvalue() lets you to set the NA value in R, but that does not affect how the TIF gets written by raster::writeRaster(). The NA values is -Inf. If I set it to -9999, save, and read the file back in I still get -Inf which is what drives the numerical issue described above.

However, I can save it as a {stars} object with write_stars(st_as_stars(r), "amro1k-stars.tif") and that solves this issue:

leaflet() %>%
        addProviderTiles("Esri.WorldImagery") %>%
        addGeotiff(
          url = "https://peter.solymos.org/testapi/amro1k-stars.tif",
          project = FALSE,
          opacity = 0.8,
          colorOptions = colorOptions(
             palette = hcl.colors(50, palette = "inferno"), 
             domain = c(0, 0.62),
             na.color = "transparent"))

Thanks for the help!