Add RasterBand::write_block

CHANGES.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+- Added `RasterBand::write_block`.
+
+   - <https://github.com/georust/gdal/pull/490>
+
 - `RasterBand::read_block` now checks that the requested type matches the band type.
 
    - <https://github.com/georust/gdal/pull/489>

src/raster/rasterband.rs

@@ -562,6 +562,41 @@ impl<'a> RasterBand<'a> {
         Array2::from_shape_vec((size.1, size.0), data).map_err(Into::into)
     }
 
+    #[cfg(feature = "ndarray")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "array")))]
+    /// Read a [`Array2<T>`] from a [`Dataset`] block, where `T` implements [`GdalType`].
+    ///
+    /// # Arguments
+    /// * `block_index` - the block index
+    ///
+    /// # Notes
+    /// The Matrix shape is (rows, cols) and raster shape is (cols in x-axis, rows in y-axis).
+    pub fn write_block<T: Copy + GdalType>(
+        &mut self,
+        block_index: (usize, usize),
+        block: Array2<T>,
+    ) -> Result<()> {
+        if T::gdal_ordinal() != self.band_type() as u32 {
+            return Err(GdalError::BadArgument(
+                "array type must match band data type".to_string(),
+            ));
+        }
+
+        let mut data = block.into_raw_vec();
+        let rv = unsafe {
+            gdal_sys::GDALWriteBlock(
+                self.c_rasterband,
+                block_index.0 as c_int,
+                block_index.1 as c_int,
+                data.as_mut_ptr() as GDALRasterBandH,
+            )
+        };
+        if rv != CPLErr::CE_None {
+            return Err(_last_cpl_err(rv));
+        }
+        Ok(())
+    }
+
     /// Write a [`Buffer<T>`] into a [`Dataset`].
     ///
     /// # Arguments

src/raster/tests.rs

@@ -12,7 +12,7 @@ use std::path::Path;
 use std::str::FromStr;
 
 #[cfg(feature = "ndarray")]
-use ndarray::arr2;
+use ndarray::{arr2, Array2, Axis};
 
 #[test]
 fn test_open() {
@@ -393,6 +393,56 @@ fn test_read_block_data() {
     assert_eq!(array[[0, 99]], 51);
 }
 
+#[test]
+#[cfg(feature = "ndarray")]
+fn test_write_block() {
+    let driver = DriverManager::get_driver_by_name("GTiff").unwrap();
+    let options = [
+        RasterCreationOption {
+            key: "TILED",
+            value: "YES",
+        },
+        RasterCreationOption {
+            key: "BLOCKXSIZE",
+            value: "16",
+        },
+        RasterCreationOption {
+            key: "BLOCKYSIZE",
+            value: "16",
+        },
+    ];
+    let dataset = driver
+        .create_with_band_type_with_options::<u16, _>(
+            "/vsimem/test_write_block.tif",
+            32,
+            32,
+            1,
+            &options,
+        )
+        .unwrap();
+
+    let mut block_11 = Array2::from_shape_fn((16, 16), |(y, x)| y as u16 * 16 + x as u16 + 1000u16);
+    let mut block_12 = Array2::from_shape_fn((16, 16), |(y, x)| y as u16 * 16 + x as u16 + 3000u16);
+    let block_21 = Array2::from_shape_fn((16, 16), |(y, x)| y as u16 * 16 + x as u16 + 2000u16);
+    let block_22 = Array2::from_shape_fn((16, 16), |(y, x)| y as u16 * 16 + x as u16 + 4000u16);
+
+    let mut band = dataset.rasterband(1).unwrap();
+    band.write_block((0, 0), block_11.clone()).unwrap();
+    band.write_block((1, 0), block_21.clone()).unwrap();
+    band.write_block((0, 1), block_12.clone()).unwrap();
+    band.write_block((1, 1), block_22.clone()).unwrap();
+
+    block_11.append(Axis(1), block_21.view()).unwrap();
+    block_12.append(Axis(1), block_22.view()).unwrap();
+    block_11.append(Axis(0), block_12.view()).unwrap();
+
+    let buf = band
+        .read_as::<u16>((0, 0), (32, 32), (32, 32), None)
+        .unwrap();
+    let arr = ndarray::Array2::from_shape_vec((32, 32), buf.data).unwrap();
+    assert_eq!(arr, block_11);
+}
+
 #[test]
 fn test_get_band_type() {
     let driver = DriverManager::get_driver_by_name("MEM").unwrap();