Add Rasterband::set_statistics

CHANGES.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+- Added `Rasterband::set_statistics`
+  - <https://github.com/georust/gdal/pull/529>  
+
 - Added `Rasterband::fill`
   - <https://github.com/georust/gdal/pull/528>
 

src/raster/rasterband.rs

@@ -1000,7 +1000,7 @@ impl<'a> RasterBand<'a> {
     /// If approximate statistics are sufficient, the `is_approx_ok` flag can be set to true in which case overviews, or a subset of image tiles may be used in computing the statistics.
     ///
     /// If `force` is `false` results will only be returned if it can be done quickly (i.e. without scanning the data).
-    /// If force` is `false` and results cannot be returned efficiently, the method will return `None`.
+    /// If `force` is `false` and results cannot be returned efficiently, the method will return `None`.
     ///
     /// Note that file formats using PAM (Persistent Auxiliary Metadata) services will generally cache statistics in the .pam file allowing fast fetch after the first request.
     ///
@@ -1033,6 +1033,26 @@ impl<'a> RasterBand<'a> {
         }
     }
 
+    /// Set statistics on a band
+    ///
+    /// This method can be used to store min/max/mean/standard deviation statistics on a raster band.
+    ///
+    /// The default implementation stores them as metadata, and will only work on formats that can save arbitrary metadata.
+    /// This method cannot detect whether metadata will be properly saved and so may return `Ok(())` even if the statistics will never be saved.
+    ///
+    /// # Notes
+    /// See also:
+    /// [`GDALSetRasterStatistics`](https://gdal.org/api/gdalrasterband_cpp.html#_CPPv4N14GDALRasterBand13SetStatisticsEdddd)
+    pub fn set_statistics(&mut self, min: f64, max: f64, mean: f64, std_dev: f64) -> Result<()> {
+        let rv = unsafe {
+            gdal_sys::GDALSetRasterStatistics(self.c_rasterband, min, max, mean, std_dev)
+        };
+        if rv != CPLErr::CE_None {
+            return Err(_last_cpl_err(rv));
+        }
+        Ok(())
+    }
+
     /// Compute the min/max values for a band.
     ///
     /// If `is_approx_ok` is `true`, then the band’s GetMinimum()/GetMaximum() will be trusted.

src/raster/tests.rs

@@ -785,7 +785,7 @@ fn test_raster_stats() {
     let fixture = TempFixture::fixture("tinymarble.tif");
 
     let dataset = Dataset::open(&fixture).unwrap();
-    let rb = dataset.rasterband(1).unwrap();
+    let mut rb = dataset.rasterband(1).unwrap();
 
     assert!(rb.get_statistics(false, false).unwrap().is_none());
 
@@ -806,6 +806,18 @@ fn test_raster_stats() {
             max: 255.0,
         }
     );
+
+    assert!(rb.set_statistics(1.0, 2.0, 1.5, 10.0).is_ok());
+
+    assert_eq!(
+        rb.get_statistics(true, false).unwrap().unwrap(),
+        StatisticsAll {
+            min: 1.0,
+            max: 2.0,
+            mean: 1.5,
+            std_dev: 10.0,
+        }
+    );
 }
 
 #[test]