Merge pull request #160 from dieghernan/stretch

Add stretch and zlim to geom_spatraster_rgb

NAMESPACE

@@ -300,3 +300,4 @@ importFrom(tidyr,fill)
 importFrom(tidyr,pivot_longer)
 importFrom(tidyr,pivot_wider)
 importFrom(tidyr,replace_na)
+importFrom(utils,packageVersion)

NEWS.md

@@ -1,6 +1,10 @@
 # tidyterra (development version)
 
 -   Add (limited) support for `SpatGraticule` (see `terra::graticule()`) #155.
+-   New arguments in `geom_spatraster_rgb()`: `stretch` and `zlim`. See
+    `terra::plotRGB()` for clarification.
+-   `geom_spatraster()` suggests `geom_spatraster_rgb()` when a `SpatRaster`
+    with RGB specification is detected (`terra::has.RGB()` is `TRUE`)
 
 # tidyterra 0.6.1
 

R/geom_spatraster.R

@@ -151,6 +151,14 @@ geom_spatraster <- function(mapping = aes(),
     ))
   }
 
+  # Kindly warn in RGB
+  if (terra::has.RGB(data)) {
+    cli::cli_alert_warning(paste(
+      "RGB specification detected. Maybe use",
+      cli::style_bold("{.fun tidyterra::geom_spatraster_rgb}:"),
+      "instead?"
+    ))
+  }
 
   # 1. Work with aes ----
 

R/geom_spatraster_rgb.R

@@ -21,6 +21,7 @@
 #'
 #' @inheritParams geom_spatraster
 #' @inheritParams scale_terrain
+#' @inheritParams terra::plotRGB
 #' @param mapping Ignored.
 #' @param r,g,b Integer representing the number of layer of `data` to be
 #'  considered as the red (`r`), green (`g`) and blue (`b`) channel.
@@ -82,7 +83,9 @@ geom_spatraster_rgb <- function(mapping = aes(),
                                 alpha = 1,
                                 maxcell = 500000,
                                 max_col_value = 255,
-                                ...) {
+                                ...,
+                                stretch = NULL,
+                                zlim = NULL) {
   if (!inherits(data, "SpatRaster")) {
     cli::cli_abort(paste(
       "{.fun tidyterra::geom_spatraster_rgb} only works with",
@@ -107,6 +110,7 @@ geom_spatraster_rgb <- function(mapping = aes(),
     ))
   }
 
+
   # 1. Work with aes ----
   mapping <- override_aesthetics(
     mapping,
@@ -125,6 +129,13 @@ geom_spatraster_rgb <- function(mapping = aes(),
   # 2. Check if resample is needed----
   data <- resample_spat(data, maxcell)
 
+  # stretch and clamp
+
+  data <- zlim_strecth(data,
+    zlim = zlim, stretch = stretch,
+    max_col_value = max_col_value
+  )
+
   # 3. Build layer ----
   crs_terra <- pull_crs(data)
 
@@ -290,3 +301,26 @@ make_hexcol <- function(data, max_col_value = 255) {
   df <- dplyr::left_join(xy, full[c("hexcol", "index")], by = "index")
   return(df[c("x", "y", "hexcol")])
 }
+
+# Strecth and clamp
+zlim_strecth <- function(x, zlim = NULL, stretch = NULL, max_col_value = 255) {
+  if (all(is.null(zlim), is.null(stretch))) {
+    return(x)
+  }
+
+  if (all(!is.null(zlim), length(zlim) >= 2)) {
+    zlim <- sort(zlim)[1:2]
+    x <- terra::clamp(x, zlim[1], zlim[2], values = TRUE)
+  }
+
+  if (!is.null(stretch)) {
+    if (all(stretch == "lin", length(zlim) == 2)) {
+      x <- terra::stretch(x, smin = zlim[1], smax = zlim[2])
+    } else if (stretch == "lin") {
+      x <- terra::stretch(x, minq = 0.02, maxq = 0.98)
+    } else if (stretch == "hist") {
+      x <- terra::stretch(x, histeq = TRUE, scale = max_col_value)
+    }
+  }
+  x
+}

R/tidyterra-package.R

@@ -6,6 +6,7 @@
 #' @importFrom grDevices terrain.colors rgb col2rgb grey
 #' @importFrom tibble as_tibble
 #' @importFrom cli qty
+#' @importFrom utils packageVersion
 NULL
 
 #' @export

codemeta.json

@@ -344,7 +344,7 @@
     "SystemRequirements": null
   },
   "keywords": ["r", "terra", "ggplot-extension", "r-spatial", "rspatial", "cran", "cran-r", "r-package", "rstats", "rstats-package"],
-  "fileSize": "2399.205KB",
+  "fileSize": "2401.527KB",
   "citation": [
     {
       "@type": "ScholarlyArticle",

revdep/README.md

@@ -3,14 +3,14 @@
 |field    |value                                                  |
 |:--------|:------------------------------------------------------|
 |version  |R version 4.4.2 (2024-10-31)                           |
-|os       |Ubuntu 22.04.5 LTS                                     |
+|os       |Ubuntu 24.04.1 LTS                                     |
 |system   |x86_64, linux-gnu                                      |
 |ui       |X11                                                    |
 |language |(EN)                                                   |
 |collate  |C.UTF-8                                                |
 |ctype    |C.UTF-8                                                |
 |tz       |UTC                                                    |
-|date     |2024-12-13                                             |
+|date     |2025-01-05                                             |
 |pandoc   |3.1.11 @ /opt/hostedtoolcache/pandoc/3.1.11/x64/pandoc |
 
 # Dependencies
@@ -37,7 +37,7 @@
 |lifecycle    |1.0.4    |1.0.4      |   |
 |magrittr     |2.0.3    |2.0.3      |   |
 |munsell      |0.5.1    |0.5.1      |   |
-|pillar       |1.9.0    |1.9.0      |   |
+|pillar       |1.10.0   |1.10.0     |   |
 |pkgconfig    |2.0.3    |2.0.3      |   |
 |proxy        |0.4-27   |0.4-27     |   |
 |purrr        |1.0.2    |1.0.2      |   |

tests/testthat/_snaps/geom_spatraster_3lyr.md

@@ -111,3 +111,10 @@
     Message
       <SpatRaster> resampled to 24 cells.
 
+# Warn in RGB tile
+
+    Code
+      p <- ggplot() + geom_spatraster(data = tile)
+    Message
+      ! RGB specification detected. Maybe use `tidyterra::geom_spatraster_rgb()`: instead?
+